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Potatoes: Organic Production and Marketing

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    Potatoes: Organic Production and Marketing Potatoes: Organic Production and Marketing Document Transcript

    • Potatoes: Organic Production and Marketing A Publication of ATTRA—National Sustainable Agriculture Information Service • 1-800-346-9140 • www.attra.ncat.orgBy Rex Dufour, This publication outlines approaches to organic and sustainable potato production. PracticesTammy Hinman and include fertility and nutrient management; organic and biorational pest management for insects,Jeff Schahczenski diseases and weeds; and storage and marketing.NCAT AgricultureSpecialists Introduction organic potato sales appear to be strong,© 2009 NCAT This publication outlines many of the it can be difficult to enter wholesale mar- practices used in organic and sustainable kets due to storage complications and potato production. While organic potato market control. These factors are Table of Contents production can yield a premium price discussed in greater detail as well.Section I: for your product, the production consid- Because each farm is a unique combi-Organic production erations are significant. This publication nation of soil, climate, environment,overview ...................................1 discusses organic soil and pest manage- management and marketing techniques,Fertility and nutrientmanagement ..........................3 ment strategies that help ensure growth it is important to plan and assess which Organic matter ...................4 of healthy and vigorous plants. Strategies practices described here are appropriate Rotations ...............................4 include choosing potato varieties suitable for a particular farm. There are numerousSection II ..................................9 for the area and intended use; using dis- potato production manuals that are spe-Weed management .............9 ease-free seed potato sources; appropri- cific to regions within the United States.Nematode management ...9 ate soil fertility and management; weed, For further information on region-specificDisease management ...... 10 disease and insect control; harvesting and potato production in general, withinInsect management...........14 methods and crop storage. your region, consult your local Coopera-Section III ............................. 21 Economic and market evaluation are tive Extension Service or call the ATTRAHarvesting ............................ 21 equally important topics in organic information line at 1-800-346-9140 forStorage................................... 23Economics and marketing potato production. While direct-marketed county extension office contacts.of organic potato Section Iproduction ........................... 23 Profile of organic potato grower: Gene Thiel ......... 26 Profile of organic potato grower: Mike Heath........ 30 Organic production overview analyses and nutrient crediting help pro- ducers avoid excess fertilizer applications.References .............................31 Organic farmers adhere to certificationFurther resources ............... 33 Sustainable farming methods also include guidelines that exclude the use of syn- thetic fertilizers and pesticides. Producers using these techniques are able to market their products as organic if they have gone through a certification process. If you are interested in becoming certified organic,ATTRA—National Sustainable ATTRA has many publications that canAgriculture Information Service(www.ncat.attra.org) is managed help you through the transition process.by the National Center for Appro- The ATTRA publication Guide to ATTRA’spriate Technology (NCAT) and isfunded under a grant from the Organic Publications will help you get offUnited States Department of to the right start.Agriculture’s Rural Business-Cooperative Service. Visit theNCAT Web site (www.ncat.org/ Organic production practices maximizesarc_current.php) for the use and recycling of on-farm nutri-more information onour sustainable agri- ent sources, including animal and green Potato plant. Photo by Dianne Earl. Courtesy of theculture projects. manures. Techniques such as accurate soil National Education Network.
    • soil-building and -conserving practices interested in transitioning to organic such as adding organic matter and potato production. minimum-tillage approaches. Biointensive The National Organic Program certi- integrated pest management is also a sus- fication standards require producers tainable farming method. to grow potatoes from organically certified The primary goal of biointensive IPM seed potatoes. The limited availability is to provide guidelines and options for of organic potato seed stock may limit the effective management of pests and the selection of specific varieties and beneficial organisms in an ecological context. larger quantities. The flexibility and environmental compati-Related ATTRA bility of a biointensive IPM strategy makes itPublications Zuseful in all types of cropping systems. Organic seed potato stock must be sourcedSustainable Soil See the ATTRA publication Biointensive for certified organic production unlessManagement Integrated Pest Management for more infor- organic seed stock is not available in the same quality, quantity or form as nonorganicBiointensive mation on this subject. stock. Examples of the quality, quantity andIntegrated PestManagement Two important factors that contribute to form clauses are: developing a sustainable and profitable farm- Quality: The same quality, such as non-Guide to ATTRA’s ing system are willingness to experiment with certified seed or disease-free seed, of potatoOrganic Publications new or different farming practices and the seed is not available .Farm-Scale Composting ability to observe how management practices Quantity: The desired variety is not availableResource List influence the farm ecosystem. Talk with as in commercial quantities.Overview of Cover growers experienced in using sustainable Form: The same variety that you typicallyCrops and Green techniques to find what methods will work in grow is not available.Manures your region. This publication includes threeIntercropping Principles profi les of growers throughout the countryand Production who are producing organic potatoes. There If you source nonorganic seed due to anyPractices is also a list of experienced organic grow- reason listed above, you must document that ers in the Further resources section of you researched at least three different seedPrinciples of Sustainable this publication. These growers agreed to sources to fi nd organic seed and that theWeed Managementfor Croplands be a resource for new farmers or farmers same quality, quantity or form is not avail-Flame Weeding for able from those sources. Also, all non-cer-Agronomic Crops tified seed must be sourced as untreated if organic seed is not commercially availableNematodes: (King, 2006).Alternative ControlsColorado Potato Beetle: Another consideration when buying seedOrganic Options is ensuring that the seed is certified as disease free (Charlton, 2008). If certi-Farmscaping to fied disease-free seed is not available inEnhance Biological the organic form, seed can be purchasedControl from a nonorganic source as allowed inNotes on Compost Tea the quality stipulation of the National Organic Program (NOP, 2006). An excerpt from the National Organic Program regulations states: § 205.204 Seeds and planting stock Organic potato stock is required by the National practice standard Organic Program unless you demonstrate the same variety, quantity or quality is not available from an (a) The producer must use organically organic seed supplier. Photo by Neva Hassanein, grown seeds, annual seedlings and plant- courtesy of Community Food and Agriculture Coalition. ing stock, except that,Page 2 ATTRA Potatoes: Organic Production and Marketing
    • (1) Nonorganically produced, untreated has been granted in accordance withseeds and planting stock may be used to § 205.290(a)(2);produce an organic crop when an equivalent (4) Nonorganically produced planting stockorganically produced variety is not commer- to be used to produce a perennial crop maycially available, except that organically pro- be sold, labeled or represented as organi-duced seed must be used for the production cally produced only after the planting stockof edible sprouts; has been maintained under a system of(2) Nonorganically produced seeds and organic management for a period of no lessplanting stock that have been treated with than one year; anda substance included on the National List (5) Seeds, annual seedlings and plantingof synthetic substances allowed for use in stock treated with prohibited substancesorganic crop production may be used to may be used to produce an organic cropproduce an organic crop when an equiva- when the application of the materials is alent organically produced or untreated vari- requirement of federal or state phytosani-ety is not commercially available; tary regulations (2006).(3) Nonorganically produced annualseedlings may be used to produce an Fertility and nutrientorganic crop when a temporary variance management Potatoes have high nitrogen and potas- sium requirements. These can be met Certified seed and certified organic by using manures, compost and crop seed stock: What’s the difference? rotations, which are detailed in the later The Western Organic Potato Pest Manage- sections. You can assess soil nutrient ment Strategic Plan offers clarification to levels with a soil test. If nutrient levels some confusion about certified disease-free are deficient, apply organic amendments. seed. This excerpt from the plan explains the difference between certified disease-free Most organic potato growers should seed and certified organic seed stock: consider producing their crop with 120 pounds of nitrogen, 25 pounds of phosphate Certified disease-free seed stock: and about 140 pounds of potash per acre “It is important that organic potato growers (Sideman and Johnson, 2006). plant high-quality, early generation, certi- fied seed to manage diseases. Certification of seed does not guarantee that the seed Seed sources for organic potato production potatoes are disease free, but that the dis- ease levels fall within certain tolerable levels. This is only a partial list. Your local organic certification organization Certification means that the seed potatoes may know of local seed sources. have met the standards of a grower-sup- Wood Prairie Farm (207) 872-8317 FAX Notes: Organic potatoes, 49 Kinney Road www.fedcoseeds.com garlic and onions ported state certification agency. Seed pur- Bridgewater, ME 04734 Order: Mail, fax chased from different states and countries Catalog: Online, print Healthway Farms are subject to different certification rules. As 1-800-829-9765 request through Web site PO Box 49 1-800-300-6494 FAX or send $2. such, each certification agency has its own Malin, OR 97632 orders@woodprairie.com Quantity: Retail and set of tolerances, or allowable amounts, for wholesale (541) 723-4725 www.woodprairie.com each disease.” scott@healthwayfarms.com Order: Online, e-mail, fax, phone Ronnigers Potato Farm www.healthwayfarms. Certified organic seed stock: Catalog: Online, print 2101 2135 Rd, com/index.html “Certified organic seed is not necessarily certified Quantity: Retail and Austin CO 81410 Order: E-mail, phone at the same specifications required for certified wholesale (877) 204-8704 Catalog: Online, print Notes: Organic seed Quantities: Smaller disease-free seed that meets stringent disease and potatoes info@ronnigers.com quantities of certified virus-free specifications and other physiological www.ronnigers.com potato and organic requirements. Certified organic potato seed is FEDCO Seeds/Moose Order: Online, e-mail, fingerling seeds up to fax, phone 10 pounds. grown in accordance with the National Organic Tubers Catalog: Online, print Program regulations (Miller et al., 2008).” PO Box 520 Quantities: Up to 50 Waterville, ME 04903 pounds availablewww.attra.ncat.org ATTRA Page 3
    • Note that nutrient requirements vary by ble to other soil amendments, but no cur- potato variety and yield goals. Lowering the rent studies support this claim. Com- soil pH will help prevent common potato post that is available on the farm should scab problems, but not powdery scab. A soil be considered as a soil amendment. pH of 5.0 to 5.2 is recommended for pre- The ATTR A publication Farm-Scale venting scab, but this pH level may affect Composting Resource List has more other crops in the rotation, as well as nutri- information about this topic. ent availability (Charlton, 2008). Sulfur is an organically acceptable way Rotations to lower soil pH. Contact your local Coop- The most important step in organic potato erative Extension Service office to deter- production is planning a crop rotation mine the correct quantities to apply based scheme that allows a few years between on your current pH, soil type and region. potato crops on the same land. For Before purchasing any sulfur amend- organic production, a lengthy rotation ment, contact your certification agent from four to seven years generally assures to obtain a list of organically accept- good plant and soil health. A lengthy able sulfur amendments. Some amend- rotation also reduces long-term relianceN utrient requirements ments have inert ingredients that are not on expensive inputs and increases the acceptable by NOP standards. percentage of marketable potatoes. vary bypotato variety and The ATTRA publication Sustainable Longer rotations can be thought of as ayield goals. Soil Management provides information form of crop insurance because the rota- about nutrient management and ref- tions help prevent plant pathogens in the erences that are useful to the organic soil from building up to economically dam- grower. Please contact ATTRA at 1-800- aging levels. Growers must consider rota- 346-9140 if you would like a copy of this tion plans with crops that are not hosts for publication or search the ATTRA Web potato pathogens or insects. The key con- site at www.attra.ncat.org. sideration for the long-term viability of organic production is preventing problems Organic matter through maintaining good soil quality. You can organically manage nutrient requirements with animal manures and Rotat ions that include cover crops composted materials. Annual application have the advantage of adding organic of these materials can provide a well-bal- matter and nitrogen to the soil. This anced, stable form of nutrients and help generally will reduce input costs over build organic matter in the soil. time. Organic matter helps soils resist compact ion, a l lows for better root In a multiyear study of sustainable penetration, stores more soil moisture potato cropping systems, researchers and allows more water penetration. Cover from the University of Maine demon- crops and green manures may include strated yield increases with the applica- legumes, sudan grass and mustards. tion of 10 tons of compost per acre. The Mustards also have been shown to play researchers also studied the economic a positive role in soil pest management considerations of applying compost and (McGuire, 2003). determined that buying compost would require a price premium on potatoes to Useful characteristics for a cover crop make the compost purchase cost-effective or green manure in a potato rotation (Porter, 2002). include: This study predates recent increases • The abi l it y to tolerate frost in conventional fertilizer prices. The and grow well under cool fall cost of compost may now be compara- conditions;Page 4 ATTRA Potatoes: Organic Production and Marketing
    • • The ability to quickly produce substantial amounts of biomass as a weed suppressant; • The ability to fix nitrogen and suppress soilborne potato pests; • A compatibility with the manage- ment requirements of other crops in the rotation; • The availability of seed and a lack of planting restrictions, such as the restriction of rapeseed production in canola districts; and • The ability to avoid producing and shedding seed, which leads to problems with volunteer plants.A good rotation includes crops that arenot hosts to common potato pests. A goodrotation also includes green manuresthat add nutrients and organic matter tothe soil (Hutsinger, 1995). Mustards used in a rotation can be a disease and nematode management strategy. Photo byThe ATTRA publications Overview of Cover Peggy Greb, courtesy USDA/ARS.Crops and Green Manures and Intercrop-ping Principles and Production Practices second year, Porter uses an adaptedprovide more detailed information about potato planter to scrape the clover fromthese subjects. Small grains, corn and sor- the ridge and plants potatoes from 2 toghum sudangrass may benefit a potato crop 3 inches deep. One week later, he killsthat follows. In Maine, some growers have the clover with a f lail chopper to pre-used Japanese millet as a cover crop in the vent competition with the potatoes. Onlyyear prior to potatoes in an effort to reduce one hilling is required, occurring sixRhizoctonia. The skin of potatoes withthe Rhizoctonia fungus appears to weeks from planting time. A second coverbe covered in dirt that won’t wash off crop could be seeded at this time,(Grubinger, 2005). In parts of the West, although harvesting operations are notproducers rotate potatoes with mustard refined to assure survival of a covercover crops to prevent root knot nematode (Porter, 2006).and Verticilium outbreaks. More informa- Porter estimates that he saves fromtion about using mustard as a disease andnematode suppressant is provided in the $50 to $60 per acre in energy costs asNematode management section below. a result of reduced tillage. His research also assesses the nutrient savings thatDr. Gregory Porter at the University of result from the nitrogen-fixing legume.Maine developed a two-year reduced- He mentioned that wheat could betillage rotation for potatoes and barley. substituted for barley. For more informationThe rotation uses red clover as a covercrop. Porter builds planting ridges in the on Porter’s research, see the final report ofspring of the fi rst year of the rotation and their Sustainable Agriculture Research andthen seeds the entire field to barley and Extension Project Report, Soil Amendmentred clover. He harvests barley in the fall and Crop Rotation Effects on Productivityand allows the red clover to continue as a and Soil Properties within Potato Productionwinter cover. In the spring of the Systems under Further resources.www.attra.ncat.org ATTRA Page 5
    • Table 1: Potato rotation chartLocation Rotation sequence Comments Contact/referencePacific 7-year crop rotation: Year 1-3: Alfalfa; This rotation works well under Mike HeathNorthwest Year 4: Row crop*; Year 5: Grain; organic production practices. (208) 539-4107 Year 6: Row crop*; Year 7: Grain Buell, ID * Dry beans, squash, potatoes and field corn are row crop options depending on marketMichigan 2-year rotation: Year 1: Potato and Research in MI has shown that poul- Annual report (2005) of the then rye planted as winter cover; try compost added to the soil under Southwest Michigan Research Year 2: Snap bean. these two-year conventional rota- and Extension Center. 3-year rotation: Year 1: Potato and tions in combination with use of www.maes.msu.edu/ then rye/vetch planted as winter cover crops can increase soil quality swmrec/publicationsfolder/ cover; Year 2: Corn; Year 3: Wheat and at least maintain yields com- Annualreports/05annualrpt/ and then clover pared to no cover crops. The three- snappenvfriendveg.pdf year rotation had a marketable yield nearly the same as the two-year rotation for comparing single har- vest years, but less than half of the scab of the two-year rotations.Maine 4-year rotation: Year 1: Potatoes; This rotation is used for organic Jim Gerritson Year 2: Spring wheat or oats, under- seed potatoes. Wood Prairie Farm sown with clover or timothy grass; www.woodprairie.com Year 3: clover sod, plowed down, year 4); Year 4: Buckwheat, plow down and then plant rapeseed as biofumigantMaine 3-year rotations, various crops : This research on various three-year Robert P. Larkin and Year 1: Soybean/sweet corn/green rotations that all included potato C. Wayne Honeycutt bean/canola; Year 2: Canola/soy- found that continuous potatoes U.S. Department of Agricul- bean/sweet corn/ barley and then decreased soil microbial activity. ture – Agricultural Research clover; Year 3: Potato Overall microbial activity were high- Service, New England Plant, est following barley, canola and Soil and Water Laboratory sweet corn. Potato crops following Orono, ME 04469 canola, barley or sweet corn provided (207) 581-3367 the lowest levels of Rhizoctonia dis- bob.larkin@ars.usda.gov ease and best tuber quality, whereas (207) 581-3363 potato crops following clover or soy- wayne.honeycutt@ars.usda.gov bean resulted in disease problems in some years. 3-year rotations: These rotations are used on a 200- Igl FarmsWisconsin Year 1: Potato; Year 2: White oats acre organic farm. Antigo, WI underseeded with clover; Year 3: *Peas are determinant grain pea, not a (715) 627-7888 Field peas*; forage pea, and can be used directly as iglfarms@verizon.net or animal feed without processing. Year 1: Potato; Year 2: Oats underseeded with clover; Year 3: AlfalfaCanada 2-year rotation: Year 1: Potato and then rye planted as winter cover; Year 2: Spring cereal with legume underseeding, legume incorporated before potatoPage 6 ATTRA Potatoes: Organic Production and Marketing
    • It is important to note that legumes such simply because there are so many fac-as peas, beans and crimson clover are tors that influence the choice of rotations,hosts to some races of Rhizoctonia (Cer- including economics of the crops in theesini, 1998) and can encourage scab in rotation, available land, weather andcertain regions. Red clover may be a host climate, farmer skills and knowledge,of Rhizoctonia as well. pest management and soil quality goals.As often happens in agriculture, there Since many of these factors are movingis no clear-cut answer to the question of targets, implementing a good crop rotationwhat rotation a farmer should use. It is a is as much an art as a science because somatter of evaluating the costs and ben- much depends on the knowledge, skill andefits of a particular practice or combina- creativity of the farmer.tion of practices. In this case, producersmust weigh the risk of these crops host- When making rotation decisions, it ising and possibly increasing Rhizoctonia helpful to have additional informationagainst the soil fertility advantages and from local experts — be they farmers,other benefits of planting a legume. extension agents or researchers — whoTable 1 (page 6) provides some exam- know about the pest pressures and soilples of potato rotations used around the and climate considerations for yourcountry. It is not meant to be exhaustive, particular region.www.attra.ncat.org ATTRA Page 7
    • Section II Weed management Organic potato producers control weeds largely by cultivation. Good field preparation, timely pest control and proper seed spac- ing provide a satisfactory stand that can also reduce weed competition. In areas with lots of weed pressure, farmers should choose specific potato varieties that put on a canopy quickly. Hilling, either with an implement or by hand, is a good way to control weeds and is a neces- sary component of potato production. In larger operations, an implement called the dammer- Root knot nematodes are common in Western organic potato systems and are the leading cause of soil fumi- diker hills and cultivates at the same time. gation in commercial potato production in the North- Complete all hilling by the time the plants are west. Photo by Jack Kelly Clark. Courtesy University of Contents 10 inches high (Sideman and Johnson, 2006). California-Davis Statewide IPM Program.Section II: Your chances of stolon pruning are high afterWeed management .............9 the plant reaches 8 inches. Stolon pruning is a et al., 2005). For more details on theseNematode management ...9 condition that causes the underground stems techniques, refer to the ATTRA publi-Disease management ..... 10 Early blight ....................... 10 to die-back, reducing yields and increasing cations Principles of Sustainable Weed Late blight .........................11 disease incidence. (Charlton, 2008). Management for Croplands and Flame Rhizoctonia ........................12 Cover cropping is also a good way to Weeding for Agronomic Crops.Insect management...........14 Colorado potato beetle14 reduce weed populations in your soil and Potato leafhopper ..........18 add soil organic matter. Results from the Nematode management Neem ...................................18 Maine Potato Ecosystem Project demon- Nematodes are microscopic roundworms strate that cover cropping with red clo- found in many habitats. Nematodes are ver and adding soil amendments such as the most abundant multicellular organ- compost and manure reduced weeds and isms on Earth. Most are beneficial enabled the potato crop to better compete members of their ecosystems, but a few with weeds (Porter, 2002). Fast-growing are economic parasites of plants. The cover crops such as buckwheat and sor- Columbia, stubby and northern root ghum sudan grass add organic matter and knot nematodes are common in Western compete with weeds. For smaller farmers, organic potato systems and are the lead- mulching with clean straw is an option that ing cause of soil fumigation in commercial builds soil organic matter and helps with potato production in the Northwest. weed populations. Root knot nematode feeding reduces the Flame weeding is another technique used vigor of plants and causes blemishes on by some growers. Flaming is also used in tubers (Westerdahl, 2007). Infection of management of the Colorado potato beetle. tubers by the Columbia and stubby root Stale seed bedding draws down the weed knot nematode often results in the for- seed bank. Irrigate or wait until after a rain mation of galls that appear as knobs or to let weed seeds germinate, and then flame swellings on the tuber surface and affect weed or cultivate. Crop rotation is another marketability. Root knot nematode lar- measure that helps keep weed problems vae invade roots or tubers, establish from becoming severe (Gallant, 1998). feeding sites and develop into the adult Producers can also significantly reduce stage. Adult females are swollen, seden- weed populations by using a drip irriga- tary and lay eggs in a gelatinous matrix tion system combined with bed planting on or just below the root surface. These instead of sprinkler irrigation (Mirabelli eggs hatch and larvae invade other rootswww.attra.ncat.org ATTRA Page 9
    • and tubers. Feeding by root knot nema- these varieties, see the ATTRA publication tode eliminates the possibility of expor- Nematodes: Alternative Controls. tation since infected potatoes are banned in many countries. Disease management There are recent promising develop- Organic management of viral, bacterial and ments with biofumigation using bras- fungal diseases begins with using certified sica mustard cover crops in a rotation seed, employing proper sanitation prac- before potatoes. Brassica crops such as tices, controlling other plant and insect rapeseed and mustard contain active vectors and using crop rotations. The two chemicals called glucosinolates. The integrated pest management (IPM) guides breakdown of these chemicals has been listed in the Pest management portion of shown to suppress some soilborne dis- the Further resources section cover these eases, nematodes and weed seeds. The topics. What follows is a brief summary of best strategy for the ultimate suppres- the diseases that are the most troublesome sion of soilborne diseases and nema- to organic potato growers and some preven- todes is selecting a species of mustard tative and control measures. that produces large amounts of biomass and glucosinolates. Also, before incor- porating, chop the green manure with Early blight (Alternaria solani) a rotary mower or a high-speed f lail Early blight is basically a disease of chopper. The breakdown of the biofu- older plants or plants that experienced migant seems to be better in moist soils, stress, such as infection by some other so irrigate following incorporation or plant pathogen or deficiencies of nitrogen time incorporation to occur with a rain or water. Excessive irrigation can also (McGuire, 2003). cause susceptibility. The lower leaves of the plant are generally infected fi rst. Jack Brown, a plant breeder specializing Early blight may appear early in the in brassicas at the University of Idaho, season, but the rate of infection accel- has released two biofumigant varieties: erates rapidly after f lowering. Tomato Humus rapeseed and IdaGold mustard. and other solanaceous plants are hosts Each variety contains elevated levels of to early blight. The disease has also glucosinolates. For more information on been reported on other plants such as some brassicas. There are several races of this pathogen. Some races are highly pathogenic while others are saprophytic and live in the soil on dead organic mat- ter. The pathogen can survive on crop debris, as a saprophyte in the soil, in infected tubers and on other hosts. The most severe damage generally occurs on early maturing potato variet- ies. However, some varieties within each maturity group have greater resistance to foliar infection by early blight. Infec- tion begins as small dark brown spots on lower leaves. As the infection spreads, the spots are restricted by the leaf veins and take on an irregular, angular look.Severe early blight symptoms. Photo by Cynthia M. Ocamb, courtesy Oregon State Close inspection of the infection willUniversity. reveal a series of dark, concentric linesPage 10 ATTRA Potatoes: Organic Production and Marketing
    • within the infected area. These lesions Table 2: Susceptibility to early and late blight.will enlarge and may coalesce as thedisease progresses. Tubers may also Highest Lowest susceptibility susceptibilitybecome infected and will have irregular-shaped, sunken lesions with somewhat *Note: Certified seed for some of these varieties may not be available.darker borders. The infection is shallow Early- and mid- Late-season Very lateand causes a brown discoloration of the season cultivars cultivars cultivarstuber flesh. These lesions can increase in Norland Russet Buttesize during storage and reduce the mar- Redsen Burbank Nooksackketability of the crop. Lesions are mosttroublesome on white, red-skinned and BelRus Kennebic Ontariochipping varieties. Norchip Katahdin Norgold RosaGrowers should select a marketablecultivar with the greatest resistance to Russetearly blight. Table 2 lists the suscepti- Early Gembility of several cultivars. The cultivar Superiorshould also fit in with other aspects of Mononaan IPM program. Water management for LaChipperearly blight prevention walks a thin line.Too much water will leach soil nitrogen. AtlanticNitrogen and phosphorus deficiencies Table adapted from: (Stevenson, 1993).can create susceptibility to early blight, Lowestbut too much nitrogen can reduce crop susceptibilityyields and delay maturity. to early and late blightGrowers should closely monitor soilferti lity, especially nitrogen levels.This can be done with petiole analysis. compost extract prepared in a 1:5 ratioInsufficient soil moisture will stress the of compost to water (volume: volume)plant and cause early senescence. This provided a level of early blight controlis a condition conducive to early blight similar to that of copper fungicide treat-development. Overhead irrigation cre- ments (Lahkim, 1999). It should be notedates ideal situations for infection and the that compost teas can be highly variablespread of foliar pathogens such as early and inconsistent. Commercial compost teasand late blight. Pay close attention to the may provide more consistency. For morefrequency, duration and timing of irri- information on making compost tea on yourgation during possible infection peri- farm, see the ATTRA publication Notes onods, since too much water can lead to Compost Tea.early and late blight. Overhead irriga-tion should be timed so plants dry prior Late blightto dew formation in the late evening andearly morning. Also, the plants should (Phytophthora infestans)also be allowed to dry early in the morn- Late blight is the most serious fungaling, prior to the start of irrigation. disease of potatoes worldwide, according to the authors of Integrated Pest ManagementA 1994 study concluded that compost for Potatoes in the Western United Statesteas can be as effective as copper fun- (Strand, 2006).gicide treatments to reduce diseasesymptoms. The study examined the use New, more virulent strains of late blightof compost teas for controlling early cause serious losses in potato varietiesblight. Results of this study indicate previously considered resistant to the fun-that spraying the plants with 14-day-old gal disease. Late blight is usually of littlewww.attra.ncat.org ATTRA Page 11
    • blight. Recent studies from the OSPUD farmer participatory research project at Oregon State University show promising late blight management using compost teas and Oxidate, a hydrogen dioxide and peroxyacetic acid product from BioSafe Systems, a manufacturer of biodegrad- able disease-control products. Some commercially available U.S. potato varieties that demonstrate resistance to late blight are the New York 121, a mid- to late-season variety; two Hungarian Sarpo varieties: the Sarpo Mira, a medium- to late-tablestock and the Sarpo Axona, a processor potato; and Remarka, an a l l-pu r pose potato ( Per r y, 20 02 ). Defender is a new late blight-resistantLate blight in potato tuber. potato cultivar that was released in Idaho,Photos by Neil C. Gudmestad, Oregon and Washington by the Tri-Statecourtesy North Dakota State Potato Variety Development Program inUniversity. 2004. Useful levels of fi eld resistance to both late blight and early blight were observed in Defender in the absence of fungicide sprays and reduced fungicide input programs (Stevenson et. al., 2007). Rhizoctonia (Black scurf, Stem canker, Rhizoctonia solani) Rhizoctonia is a pathogen present in all potato-growing areas. Most damage occurs concern in the western United States, during the early part of the growing sea- except in the coastal valley regions where son, particularly when infected tubers are late blight occurs regularly. Its occur- planted. Cold, wet soils can increase prob- rence in other regions of the United States lems with this disease. is dependent on both the presence of the pathogen and cool, damp weather. The fungus survives in the soil either as Blight forecasting still occurs quite mycelia associated with decomposing plant regularly to help alert growers when residues or as sclerotia, the dirt that won’t conditions are conducive to the disease. wash off unharvested tubers. Soilborne For more information on blight fore- infections, known as the chronic phase casting, contact your local Cooperative of the disease, generally will not infect Extension System office. sprouts. Instead, soilborne infections cause a decrease in tuber quality and yield by Sanitation is the best defense against pruning tubers and causing reddish-brown late blight. Eliminate all cull piles and lesions that may develop into cankers. control volunteer potato sprouting the following spring in areas where there was Tubers may also be malformed, cracked, an incidence of late blight. pitted or display stem-end necrosis. Young plants that develop from infected Copper products are currently allowed by seed pieces are most severely affected. NOP standards and are the most effective Sprouts may be completely girdled by means of controlling and preventing late lesions and killed. Partially girdled stemsPage 12 ATTRA Potatoes: Organic Production and Marketing
    • will slow growth and development and mayresult in stunting and rosetting of plant tops;purple pigmentation of leaves; upward leafroll; and chlorosis, which is usually mostsevere at the top of the plant.Potato growers can manage Rhizoctonia withmonitoring. It is useful to keep good recordsof the existence and severity of black scurfproblems in each field. This way, fields witheconomically damaging levels of black scurfcan be managed through appropriate rota-tions and other methods.Cultural controlsAvoid growing sugar beets prior to pota-toes because sugar beets tend to increase Rhizoctonia (Black Scurf) in tubers of potato. Photo by Neil C. Gudmestad, courtesyRhizoctonia problems. Avoid a rotation North Dakota State University.with buckwheat before potatoes becauseRhizoctonia colonizes mature buckwheat surface of tubers under cool, moist condi-stems (Leach and Specht, 1987). Crop tions, usually after the vine starts to die.rotation to nonhost crops such as cere-als for at least two years can reduce Biological management optionsdisease incidence. A three- to fi ve-year Research in greenhouses and in therotation away from potatoes is recom- field shows that dusting seed pieces withmended if disease incidence is severe fungal antagonists of Rhizoctonia can(BASF Canada, 2005). significantly reduce stem canker andIt should be noted that recent protein- and black scurf (Beagle-Ristaino and Papavi-DNA-based studies of Rhizoctonia found zas, 1985). This reduces Rhizoctoniaconsiderable genetic diversity in Rhizocto- infection and decreases the viability ofnia and its hosts (Ceresini, 1998). Grow- sclerotia on the potato. The commerciallyers should be careful when selecting rota-tion crops. Generally speaking, cereals area safe bet. Crops closely related to potatoes, Cultural management optionssuch as tomatoes, eggplants and peppers, for Rhizoctonia:along with volunteer potatoes, may host Rhi- • Plant potatoes when soilzoctonia and should not be used in a potato temperature is above 60rotation. Likewise, related weeds such as degrees Fahrenheit.black nightshade and Jimsonweed should • Avoid irrigation before thebe kept out of the field. expected harvest.Planting certified seed significantly • Plant seed pieces no morereduces poor stands and sprout death than 2 inches deep. Theassociated with Rhizoctonia. For a defi ni- temperature of the soil istion of certified seed, see the box on page warmer at this depth.three. However, using certified seed will • Harvest potatoes as soon asnot eliminate Rhizoctonia problems since skin set occurs after vine kill tothe fungus survives in the soil either as avoid development of sclerotiamycelia associated with decomposing plant on mature tubers in the soil (Rowe et al., 1995).residues or as sclerotia on unharvestedtubers. The sclerotia may form on thewww.attra.ncat.org ATTRA Page 13
    • available fungal antagonists featured Insect management in the study include Trichoderma viride and Trichoderma virens. There is a list Colorado potato beetle of commercial products formulated with (CPB, Leptinotarsa decemlineata) fungal antagonists of Rhizoctonia, as well as contact information for manufac- Many insect pests are associated with potato turers of the microbial pesticides, in the production. Because the Colorado potato Fur ther resources section of this beetle (CPB), Leptinotarsa decemlineata, is a major insect problem in potatoes, we focus publication. The ATTRA publication on acceptable approaches to control this pest Biointensive Integrated Pest Management in organic production. The ATTRA publica- has more information on using fungal tion Colorado Potato Beetle: Organic Control antagonists. Options provides more detail about managing Many scient i f ic invest igat ions have this pest. ATTRA also has information about examined various aspects of biologi- control techniques for other pests, such as cal control of Rhizoctonia (Jager and the blister beetles and aphids. Velvis, 1986; Lewis and Papavizas, 1987; Howell, 1987). More recent research shows that some readi ly ava i lable commercial biocontrol products reduce the development of stem lesions in the field, with control comparable to that of a standard chemical treatment. However, no treatments, including chemi- cal control, substantially reduced black scurf on potato tubers. Some treatments resulted in higher total yield, as well as Immature Colorado potato beetle. Photo by Tom Murray. higher yield of larger potatoes. Although no treatments effectively controlled black scurf, all biocontrol treatments controlled stem canker and some resulted in greater overall yield and larger potatoes (Larkin and Talbot, 2002). Recent studies in Washington show that mustard green manures may offer farm- ers an equally effective but less expen- sive alternative to fumigants for control Adult Colorado potato beetle. Photo by Tom Murray of soilborne pests (McGuire, 2003). The fi ndings from this study suggest poten- tial for mustard green manures to replace the fumigant metam sodium for potato production in some cropping systems. The practice can also improve water infi ltration rates and provide substantial savings for farmers. While Rhizoctonia is not mentioned in the above study, another Colorado potato beetle eggs are bright orange and recent study found that mustard biofumi- typically located on the undersides of leaves. gants reduced incidence of Rhizoctonia in Photo by Whitney Cranshaw, courtesy Colorado a greenhouse setting. State University.Page 14 ATTRA Potatoes: Organic Production and Marketing
    • The CPB is native to the United States. Its A combination of several strategies can helporiginal range was restricted to the east- keep CPB populations under control. Cropern part of the Rocky Mountains. In the rotation, preferably with field corn, wheatRockies, the beetle fed on buffalo burr, or some other crop that can tolerate a pHa plant of no economic importance. Once of 6.0, can delay CPB population buildup.the potato was introduced to this region, Ideally, rotated fields should be isolatedthe beetle moved to the crop and spread from the previous year’s potato planting.eastward from potato patch to potato patchand reached the East Coast by 1874. The Cultural techniques to managebeetle is now found throughout North Amer- the CPBica, except in parts of Florida, Nevada, The effect of crop rotation on populationsCalifornia and eastern Canada. By 1935 of CPB and on the incidence of early blightthe CPB was established in France and is caused by Alternaria solani is quantified innow widespread in Eurasia. a 1994 study (Weisz). The study noted thatThe CPB is the most economically threat- infestations of both pests are inversely relatedening pest of potatoes in the northeastern to the distance between rotated fields and theUnited States. If left uncontrolled, this pest nearest location where potatoes were planted T hecan completely defoliate a potato crop by late in the previous season. In other words, the ColoradoJuly (Hollingsworth et al., 1986). Although farther you plant this season’s potatoes from last season’s potato field, the fewer pest prob- Potato Beetlethe potato is its favorite food, the beetle mayalso survive on tomato, eggplant, tobacco, lems will occur. is also the mostpepper, ground cherry, thorn apple, Jimson- economically Research at Cornell University demon-weed, henbane, horse nettle, belladonna, strated the efficacy of flame technology in threatening pestpetunia, cabbage, thistle, mullein and other controlling overwintering CPBs. The most of potatoes in theplants (Metcalf and Flint, 1962). The CPB effective time for flaming is between plant northeasternis resistant to most registered pesticides, emergence and when the plant reaches 8 United States.making the beetle one of the most difficult inches in height. Taller plants are less heatinsect pests to control in cultivated crops tolerant and their canopy shields many(Hollingsworth et al., 1986). of the pests. The best control is achieved on warm, sunny days when beetlesThe life cycle of the beetle varies accord- are actively feeding on top of the plants. Ining to where it is found. In northern Maine, trials, flaming provided 90 percent controlthe CPB completes one generation per year. of overwintering adult CPBs, contrastedFarther south, the CPB completes three with from 25 to 50 percent with chemi-generations per year. The adult beetle over- cal insecticides. Flaming also reduced eggwinters in the potato field, from 12 to 18 hatch by 30 percent (Moyer, 1992).inches below the soil surface and in pro-tected sites around the field. The beetles The CPB ca n be excluded f romemerge in late spring, move to the field and crops with the use of floating row covers.mate once established on a plant. Females Floating row covers are thin fabrics spunlay egg masses on lower leaf surfaces in from a synthetic material. The productbatches of approximately 25 eggs. A single allows air and moisture to pass throughfemale may lay up to 500 eggs. Because the while preventing pest species access toeggs are laid in clumps, the larvae tend to the plants. The floating row covers shouldbe found in clumps rather than randomly be put on either shortly after plantingthroughout the field (Hollingsworth et al., or emergence.1986). You can fi nd good life cycle infor- Straw mulch of wheat or rye in potatomation for the CPB in the book Destructive fields may reduce the CPB’s ability toand Useful Insects, by Metcalf and Flint, locate potato fields and alter the microen-1962. The book is available from most vironment in favor of CPB predators (Brust,agricultural libraries. 1994). In the fi rst half of the season, soilwww.attra.ncat.org ATTRA Page 15
    • predators — mostly ground beetles — climb field borders or by planting insectary strips potato plants to feed on second- and third- in the field can increase the effectiveness stage instar larvae of the CPB. In the sec- of these biological controls. ATTRA has ond half of the season, lady bird beetles more information on this technique in and green lacewings are the predominant the publication Farmscaping to Enhance predators and feed on eggs and fi rst and Biological Control. second instars. The increased number of Several plants, such as tansy and catnip, predators in mulched potato plots com- are reported to repel the CPB. Two jour- pared to non-mulched plots resulted in sig- nal abstracts from The IPM Practitioner nificantly less defoliation from the CPB and discuss interplanting trials conducted at one-third higher tuber yields. Rodale Institute Research Center in coop- eration with USDA researchers (Olkowski, Varietal resistance to the CPB et al., 1992). The experiments show tansy Some potato varieties, such as Russet and catnip were from 58 to 100 percent Burbanks, seem to be more tolerant to effective in repelling the CPB from pota-S ome potato varieties, the CPB, but no varieties are completely toes. However, a European study shows that resistant. The April 1989 issue of National companion planting did not significantly such as Russet reduce plant defoliation by the CPB. In the Gardening highlighted research on plantingBurbanks, seem to be early maturing varieties that develop potato European study, companion plants weremore tolerant to the tubers before CPB populations explode. smaller than the potatoes in the begin-CPB, but no varieties It listed seven varieties that mature from 75 ning of the season. The study’s authorsare completely to 88 days. The varieties are the Caribe, speculated that more mature companion Norland, Pungo, Redsen, Sunrise, Superior plants might be more effective (Moreau etresistant. and Yukon Gold. The issue also illustrated al., 2006). In 1992, The IPM Practitio- the growth stages of the potatoes and how ner published a special report specifically the stages coincide with CPB emergence addressing potato IPM for the CPB. The and larval development (Ruttle, 1989). This issue can be ordered as a photocopy from the publisher. See the Further resources practice of using early maturing varieties section for ordering information. may prove beneficial to growers in northern regions of the United States, where cooler Parasitic nematodes are another con- temperatures slow insect development. trol option. Commercial formulations of Heterorhabditis species are available and Biological controls of the CPB have been shown to be more pathogenic (Berry, et al., 1997) to the CPB than Stein- There are several natural enemies of the ernema species, which is also commercially CPB, but these enemies are rarely seen available. The Ohio State University Web in commercial potato fields because of site portal for beneficial nematodes, avail- heavy pesticide use. Even under organic able at www.oardc.ohio-state.edu/nematodes, growing conditions, when natural enemies provides helpful information on how to use are abundant, the beetle can still cause and where to obtain beneficial nematodes. defol iat ion. The genera l predators, such as lady bird beetles, lacewings and Biorational controls for the CPB stink bugs, provide some control of the CPB, as do several parasites. Dorypho- Commercially available M-One is a prod- rophaga doryphorae and D. coberrans, two uct manufactured by the Mycogen Corpora- species of fly that invade the larvae; and tion of California. See contact information in Edovum puttleri, a wasp that parasitizes the Further resources section for order- ing information. This biopesticide is made CPB eggs; were recently introduced and from Bacillus thuringiensis (Bt) var. ‘San are commercially available. Diego’, a naturally occurring bacterium, Increasing habitat for natural enemies by and is effective for controlling CPB with- providing pollen and nectar sources along out disrupting beneficial organisms. It is,Page 16 ATTRA Potatoes: Organic Production and Marketing
    • however, a genetically engineered product materials will work best in situations withand is not acceptable in organic certification moderate to high relative humidity.programs. Entrust is a new formulation of SpinosadSome research indicates that sprays of manufactured by Dow AgroSciences. It isBacillus thuringiensis species tenebrionis registered for use on organically managed(Bt) will cause significant mortality of CPB farms to control the CPB and is popular withlarvae upon emergence from their eggs. organic farmers. The contact information toThis is because the beetles gnaw out of find a distributor near you is listed at the endthe eggs and continue eating the shells of this publication in the Further resourcesafterward, therefore also ingesting Bt section.particles (Ghidiu et al., 1994). Several neem-derived products areMycotrol-O, a formulation of the parasitic registered for use against the CPB.fungus Beauveria bassiana, is available from Soft-skinned larvae of CPB are reportedlyLaverlam International, based in Butte, killed on contact. In a two-year study of vari-Mont. This product is an effective control of ous organic techniques for controlling CPBthe CPB by itself or when used in combina- in the United Kingdom, a 2-percent formula-tion with Bacillus thuringiensis var. tenebri- tion of Neemix increased yield and loweredonis (Jones, 1999). Some formulations use beetle densities and the occurrence of defo-different strains of B. bassiana. Each strain liation significantly.has the greatest efficacy against a slightly The ATTRA Biorationals: Ecological Pestdifferent group of insects, so be sure to read Management Database, available at www.attra.the label or ask a sales representative about ncat.org/attra-pub/biorationals/biorationals_which formulations are most effective against main_srch.php, lists several organically accept-the CPB. Since these are all formulations able biorational pest management materials forwith a fungus as the active ingredient, the the CPB. Several of these materials are listedTable 3:Reduced Risk Pest Management Manufacturer Active ingredient OMRI listed*Agroneem Agro Logistic Systems Azadirachtin YesAgroneemPlus Agro Logistic Systems Azadirachtin YesEcozin AMVAC Chemical Corp. AzadirachtinOrnazin AMVAC Chemical Corp. AzadirachtinBiorin Biotech International Beauveria bassianaAzatin XL Plus Certis USA, LLC AzadirachtinNeemix 4.5 Certis USA, LLC Azadirachtin YesDiatect V Diatect International Diatomaceous Earth (Sili- con Dioxide)Conserve sc turf and ornamental Dow AgroSciences LLC SpinosadEntrust Dow AgroSciences LLC Spinosad YesSpintor 2sc Dow AgroSciences LLC SpinosadSuccess Dow AgroSciences LLC SpinosadFortune Aza Fortune Biotech Limited AzadirachtinPyola Gardens Alive!, Inc. PyrethrinsAnti-pesto-o Holy Terra Products, Ltd. Azadirachtin* OMRI is the Organic Materials Review Institute. If a product is OMRI approved, it is allowed for use in certified organic sys- tems. Contact your certifier before using any organic pesticide to ensure it is approved by the National Organic Program.www.attra.ncat.org ATTRA Page 17
    • above in Table 3. The database also provides selective. Anagrus species of trichogrammatid information about using cultural controls to wasps might be available at a local insectary prevent pest problems. and are effective against leafhopper eggs in inundative releases. Potato leafhopper Even if this particular species is not avail- (Empoasca fabae) able, you might consider an inundative The potato leafhopper, Empoasca fabae, does release of a generalist Trichogramma egg not overwinter in the northern United States parasite, as Trichogramma species tend and must migrate annually. The potato leaf- to parasitize whatever eggs are available. hopper is one of several closely related leaf- Make sure you check with the insectary hoppers in this genus. The potato leafhop- about parasite host ranges. Other benefi- per feeds on more than 200 cultivated and cial insects are green lacewing, lady beetle, wild plants including beans, potatoes, egg- minute pirate bug, assassin bug, syrphid fly, plant, rhubarb, celery, dahlia, alfalfa, soy- hover fly, robber fly, spiders, damsel bugs beans, clovers and sweet clover. A high and big-eyed bugs. migration rate and wide host range make control of the potato leafhopper difficult. The Department of Pesticide Regulation, part of the California Environmental Both nymphs and adults feed on the under- Protection Agency, publishes a booklet sides of potato leaves. By extracting the sap, called Suppliers of Beneficial Organisms potato leafhoppers cause stunting and leaf in North America. The most recent curl. Potato leafhoppers also bring on hop- version, from 1997, lists 143 commer- perburn, a disease caused by the injection of a toxic substance. Hopperburn is charac- cial suppliers of more than 130 beneficial terized by a yellowing of the tissue at the tip organisms used for biological control. It is and around the margin of the leaf. The yel- available for free download at www.cdpr. lowing increases until the leaf dies. Symptoms ca.gov/docs/ipminov/bscover.htm. are sometimes confused with drought stress (Bennett et al., 2007). Neem Neem works best when ingested by pests The ATTRA publication Farmscaping to and is effective for controlling leaf-eating Enhance Biological Control describes how to pests. Although neem is not effective for design your farm to favor predatory organ- controlling sucking insects such as leafhop- isms. These techniques can be integrated in pers, it appears that it still could be part a biointensive IPM program and can help of a biocontrol strategy targeted against the make your cropping system friendlier to insect. Neem shows considerable anti-feed- beneficial organisms. ant and growth-regulating effects on leaf- Biological control hopper nymphs (National Research Coun- cil, 1992). Neem is primarily an insect Leafhoppers have several growth regulator and should be applied parasites and predators. early in the crop cycle. It is essential to get The mirid bug, Cyrtorhinus good leaf coverage and to see that the neem species and specifically product adheres to the leaf surface. If not, Cyrtorhinus lividipennis, the nymphs, which feed on the undersides is an effective predator. of the leaves, will not contact the active Some members of the ingredient. The nymphs should be targeted wasp family are parasites because leafhoppers are most vulnerable in of leafhopper eggs. Some this stage. species of TrichogrammaPotato leafhoppers cause hopperburn, a disease are generalist egg para- The IPM Practitioner notes that gar-with symptoms that are sometimes confusedwith drought. Photo by Art Hower, courtesy sites and have a wide host lic sprays can signif icant ly reducePennsylvania State University Department of range. Other species of leaf hopper populations, although theEntomology. Trichogramma are more resulting numbers are still unacceptablyPage 18 ATTRA Potatoes: Organic Production and Marketing
    • high. Garlic may increase the efficacy of these interspecies crosses, including Kingother leafhopper pest management strat- Harry, protect themselves from pests byegies. Insecticidal soap penetrates the arming their leaves and stems with hairsinsect’s cuticle, disrupts the cell mem- fi lled with sticky fluids. These trichomesbranes and causes death by dehydration. explode when touched, miring small insectsThis method is likely to work best against such as leafhoppers and flea beetles innymphs (Olkowski et al., 1992). Efficacy is goo. The trichomes also ruin the appetites ofvariable with this method as well. hungry Colorado potato beetles, reducing or eliminating the need to use other pest controlAlternatively, a water spray directed at the measures (Pleasant, 2007). King Harryplant, especially under the leaves, will seed potatoes are available in limited quan-wash off the insects. This treatment is not tities from Wood Prairie Farm in northernrecommended in humid weather because of Maine. See the Potato seed stock box onpossible disease problems. Take care not page 3 for more information.to use excessive force. Spray early in themorning, especially in hot weather (Bradleyand Ellis, 1992). Other physical controlsinclude the use of floating row covers dur- OSPUDing the first month to keep leafhoppers out. A new kind of research andPyrethrin, rotenone and sabadilla are rec- information sharingommended only as a last resort. Rotenone is Eleven organic farmers in Oregon and Washington are workingnot approved by the NOP standards and has closely with Oregon State University faculty members to improveheavy restrictions from the Environmental potato quality and profitability through a participatory learningProtection Agency. process and on-farm, farmer-directed research.A new variety of potato called King Harry, This project encourages an exchange of existing knowledge of integrated management techniques and promotes farmer inno-and the earlier Prince Harry, are the result vation. OSPUD’s goal is to learn more about the wide variety ofof three decades of work by Cornell Uni- management issues, including soils, nutrients, insects, diseases,versity potato breeder Bob Plaisted. The weeds, tuber quality and profitability, facing small organic potatopotatoes have shown resistance to small farmers in the Northwest.insects such as leafhoppers and flea beetles. This project has generated a number of useful publications forStarting in the late 1970s, Plaisted began organic potato production. For more information and access tocrossing Katahdin and other mainstream these publications, visit http://ospud.org.varieties with Solanum berthaultii, a wildpotato from Bolivia. The most successful ofwww.attra.ncat.org ATTRA Page 19
    • Section III Harvesting from Market Farm Implement Company at www.marketfarm.com/index.cfm. The Spedo Timely vine killing is essential for good tuber Potato Planter is a cup-type potato planter separation from stolons, tuber skin set, and that automatically plants cut or graded seed efficient harvest. But many farmers do not potatoes and other similar-size tubers. It is prematurely kill vines (Vales, 2004). Harvest- imported from Italy. The Spedo Potato Planter ing procedures for organic potatoes require plants the tubers from 6 to 13 inches apart in alternatives to chemical desiccants. Mechan- the row and hills the row at the same time. It ical destruction is one method and flaming is available as a one- and two-row model. Row technology is an alternative. Flame weeding is spacings are adjustable from 26 inches plus. used successfully to top-kill the potato vines. Woody Gerritsen of Wood Prairie Farm does US Small Farm, formerly Afiveplus, from two passes with a propane flame weeder to Torrington, Wyo., is also a source for top-kill the potato vines before harvest. Many small- to medium-scale potato planting and growers also use a flail chopper that, if the harvesting equipment. In 1998 Afiveplus Contents equipment is present on your farm, can reduce began manufacturing and selling small-scaleSection III:Harvesting ............................ 21 propane costs associated with flaming. potato equipment. Owners Larry and DeeDee Anderson, along with their son Eric, make Profile of organic potato Immediately after harvest, healthy potatoes grower: Ivy Donovan ..... 22 potato planters specifically suited for the small should be cured by holding them for 10 toStorage................................... 23 farm. After the first year of digging their ownEconomics and marketing 14 days at 50 to 60 degrees and high rela-of organic potato potatoes, the family developed a small dig- tive humidity with good air movement to per-production ........................... 23 ger to add to the product line. Smaller prod- Evaluating economics mit suberization and wound periderm for- and markets ..................... 23 ucts developed over the years include a small mation, or the healing of cuts and bruises. Organic potato table-model seed cutter and hilling discs. industry ........................... 24 Although wound periderm formation is most Contact information is listed in the Further Emerging organic market structure ........................... 25 rapid at about 70 degrees, lower temperatures resources section of this publication. Market segments .......... 25 are recommended to reduce decay. Curing Marketing difference ... 25 reduces subsequent weight loss and decay by Price premiums and preventing the entry of Fusarium, soft rot and cost of production ......... 26 Profile of organic potato other decay organisms. The relative humidity grower: Gene Thiel ........ 26 should be about 95 percent (Vales, 2004). Two comparative studies of organic and conventional potato Seed cutters, planters, harvesters, washers production costs ........... 28 and storage rooms make large-scale potato Estimating costs and profitability for organic production a significant financial commitment potato production ....... 29 for any larger-scale grower. The Igls family, The emerging processed organic potato who farms 43 acres of potatoes in Antigo, industry ............................ 29 Wis., customized and adapted almost all of Profile of organic potato grower: Mike Heath ...... 30 their equipment to refine their organic oper-References .............................31 ation (Padgham, 2002). Most medium-scaleFurther resources ............... 33 mechanized organic producers have one or two pieces of used equipment; potato dig- The Spedo brand has a potato digger that is a two- gers are most common. Auctions and dealers row, three-point hitch-mounted digger for tractors located in traditional small-scale potato pro- (above left). This model straddles two rows of hilled duction areas, such as south of Montreal, are potatoes. The potatoes must be grown in a hill for the digger to work properly. Also, the Zaga Potato Digger good sources for equipment. Increased mech- (above right) is a one-row, three-point hitch-mounted anization allows farmers to grow on more power-take-off (PTO) powered digger. It is designed acres. That often, but not always, reduces the for use on tractors that straddle one row of potatoes centered under the tractor since the digger cannot be unit cost of production (Caldwell, 1999). offset. It will only dig hilled potatoes because the shoe cannot be adjusted to go below ground level. Some mechanical options for planting and Photos courtesy of Market Farm Implement, harvesting on a medium scale are available www.marketfarm.comwww.attra.ncat.org ATTRA Page 21
    • Profile organic potato grower: Ivy Donovan This is an excerpt used with permission from The Natural Farmer Fall 2006 newsletter. Ivy Donovan currently has about two and a half acres in pota- toes. The potatoes are planted in long rows near the house, each row about a quarter of a mile long. Donovan does all the work himself and has specialized equipment for each stage. For planting, he uses a two-row planter that opens up the row, puts the organic fertilizer in, drops in the seed and cov- ers it up. He cuts potatoes for seed by hand, sitting on a seed cutting horse with the radio on. For cultivation Donovan uses a spring-tooth weeder. After awhile the potato plants get so big Donovan can’t use the cultivator any more because he’d do too much damage. So every morning he spends the first half hour walking through Donovan’s two-row harvester cuts under the potatoes and brings the potatoes picking weeds. the entire hill up and over the moving rods. The dirt falls between When Donovan harvests potatoes he takes the tops off and the rods and the potatoes are carried to the back and dropped onto the ground. Photo by Jack Kittredge, courtesy of waits two weeks for the skins to get tougher and the potatoes The Natural Farmer. to cure before digging them. For taking the tops off, he also uses his father’s equipment: Donovan and his father used a regular harvester when they “Back in the (1950s) we’d use a roto-beater to take the tops were harvesting 60 acres of potatoes. But when Donovan off. It had rubber fingers and you would go through and beat started growing organic he got the old two-row digger out. the tops off,” Donovan said. “Then the vines would die back He explains: “The big harvester would bruise a lot of the pota- and in two weeks you could dig them. Well, I got that out toes on this kind of ground. And all your smaller ones would and we’re using it. I had to take my chain saw to get it out of shake right through and you’d lose them. But today those where it was.” small potatoes are an excellent item. A lot of people want them. We’ll mix all different colors of creamer size and sell Donovan also built a weed flamer. Once the tops are off the them. People will pay extra.” potatoes, the weeds will start growing. Then, when it comes time to harvest he has to pick through weeds. So Donovan The two-row digger brings the spuds up, the dirt falls through goes through with the flamer once the weeds start poking up properly spaced rods and the potatoes are carried to the end and kills them while the potatoes are still under cover. and laid on the ground behind the digger for hand picking. The bar cuts just to the bottom of the hill, lifts the whole hill up and shakes the potatoes free. The sprockets have removable long and short arms that can raise and lower the rods rapidly to shake the dirt free. That shaking is great if the ground is wet, but if it is too dry and Donovan doesn’t want to drop the dirt too soon he can take those arms out and the shaking stops. Donovan’s digger has a gearbox mounted on the shaft com- ing from the PTO. “They don’t come through from the factory with a transmission on it,” he laughs. “That was the first thing my father did was put that transmission on. It gives you more control to run it faster or slower, depending on the conditions of the field. Nowadays you have more gears on your tractor so you don’t need the transmission as much.” Donovan also has a potato washer and a grading machine to screen out the smaller potatoes so he can pack them sepa- rately. Potato grades are A, or full size; B, the smaller potatoes; creamers, which are golf ball size; and babies, which are the size of a thumbnail. There is also a storage building, built in 1956. Donovan’s father insu- lated it and used wood stoves for heat. Some winters, he recalls, it Ivy Donovan. Photo by Jack Kittredge, courtesy of The Natural Farmer. got 10 degrees below zero and they had all the stoves going.Page 22 ATTRA Potatoes: Organic Production and Marketing
    • Storage A major component of managing potato quality in storage is effective sprout inhi-Good storage should prevent excessive dehy- bition. Sprouting causes increased weightdration, decay and sprouting. Maintaining loss, reduces tuber quality and impedes airgood sanitation, adequate humidity and appro- movement through the potato pile. Preven-priate temperatures in storage facilities, com- tion of sprouting is one of the Achilles’ heelsbined with adequate curing of harvested pota- of storing large quantities of organic pota-toes, are important considerations, particularly toes. The use of essential oils and hydrogensince organic growers do not have the array of peroxide is a recent development in sproutchemical controls available that conventional inhibition and is approved by the NOP.growers have. Helpful practices include: Mint and clove oils applied through wick • Thoroughly clean the storage space application are effective at suppressing and machinery of all potato debris sprouts. The oils appear to work by burn- and excess dirt, using a pressure ing the sensitive meristimatic sprout tissue. washer and steam as needed. Although both oils have suppressive qual- • Disinfect equipment and the storage ities, peppermint oil tends to cause less structure with organically approved problems with culinary and palatability G materials and methods. Contact ood concerns. Clove oil is a more effective sup- your certifier for more information. pressant when applied as a thermal aerosol. storage • Perform routine maintenance and Hydrogen peroxide is also allowed by NOP should repairs on ducts and structure as standards, however some products may con- prevent excessive needed. tain adjuvants that are not allowed. Check dehydration, decay • Clean dust, dirt and sprout inhibi- with your certifier to make sure products and sprouting. are approved by the NOP. Oils are typically tors from fan blades. applied through the humidification system • Check dampers and louvers for free in storage. Frequent and repeated appli- movement and function of limit cations are necessary for long-term sprout switches. control. These products also demonstrate • Be certain all motors are lubricated the ability to inhibit postharvest diseases in and working and that belts are in laboratory studies, but this research has not good condition. been extended to storage facilities (Frazier • Check all thermostats, humidistats et. al., 2004). and controls. • If needed, wet the storage floor to Economics and marketing of help maintain high humidity. organic potato production • Humidify and pre-cool the storage area to from 55 to 60 degrees a few Evaluating economics and days before introducing the potatoes markets (Brust, 1994).The following figures should be considered Backgroundwhen building or renting storage facilities The conventional potato industry is distin-(Vales, 2004): guished by large-volume production of a fairly uniform commodity crop produced1 hundredweight (cwt) of potatoes occupies by farmers who are highly specialized in2.3 cubic feet.; 1 cubic foot of storage holds potato production. The biggest segment of0.42 cwt of potatoes the market is potatoes grown for direct con-total cwt of bulk stored potatoes = (pile sumer consumption and potatoes that arelength x pile width x pile height)* / 2.3 processed. The rapid increase since the end of World War II in the consumption of the Pile dimensions in feet. * dehydrated potatoes, frozen potatoes, potatowww.attra.ncat.org ATTRA Page 23
    • chips and the ubiquitous French fry led to Economic Research Service, U.S. per-capita enormous demand for the processed potato. use of frozen potatoes was 56 pounds per In 2004, more than 41 billion pounds of year, compared with 45 pounds for fresh potatoes were sold by farmers in the United potatoes, 17 pounds for potato chips and 16 States. In 2005, according to the USDA pounds for dehydrated products (2005).Table 4: Like all commodity crops, the structure of the conventional potato industry is aCertified organic potato acreage by state, 1997-2004* concentrated market situation with manyYear 2004 2003 2002 2001 1997 producers but so few buyers that the buyersAlaska 36 85 can exert considerable control over marketArkansas 100 1 price. For a good discussion of this kind ofCalifornia 3,654 3,057 2,434 3,734 1,091 market and the famous Idaho potato indus- try, see Fast Food Nation, 2001, by EricColorado 1,260 1,370 1,457 1,604 905 Schlosser. For another interesting exampleConnecticut 11 see Market Power for Farmers by RichardDelaware 4 Levins, 2005.Hawaii 23 5 Over time, this commoditization and con-Idaho 298 357 357 565 618 centration of market power in the potatoIllinois 3 39 industry led to a decrease in the numberIndiana 0.1 of smaller conventional producers. TheIowa 1 9 8 4 1 margin for profitable production is increas- ingly narrow and more acreage is requiredKansas 0.3 to maintain income from production. Aver-Maine 165 160 160 78 10 age seasonal prices to farmers during theMassachusetts 36 last 20 years ranged from a high of $10.80Michigan 1 70 43 39 1 per cwt in 1989 to a low of $5.05 per cwtMinnesota 5 7 124 45 127 in 1996 for table-grade potatoes. Process- ing potatoes fetch less in the conventionalMissouri 6 potato market, with a high of $5.21 perMontana 11 cwt in 1995 and a low of $3.85 per cwt inNebraska 1 2 1 1987. To get a sense of just how tight mar-Nevada 20 gins are in the conventional potato market,New Hampshire 5 10 consider that even at $5.21, the highest sea- sonal price for processing potatoes over theNorth Carolina 186 2 last 20 years, researchers at the UniversityNorth Dakota 122 111 427 167 88 of Idaho estimate that the average producerOhio 6 7 74 14 4 in 2005 would not likely see a significantOklahoma 10 positive return from production (PattersonOregon 520 76 148 222 68 et al., 2005).Pennsylvania 5 17 10 29 1 One countering effort to this situation is theRhode Island 1 1 1 fairly recent development of farmer-basedSouth Dakota 2 1 1 0.3 supply management cooperatives that are attempting to counter buyer market powerTexas 41 113 64 407 by balancing supply and demand to restoreUtah 142 and maintain profitability for its farmerWashington 846 1,142 1,122 599 645 members.Wisconsin 103 113 114 172 173Total U.S 7,300 6,569 6,593 7,533 4,336 Organic potato industry*ERS data for organic potato acres for 1997 and 2000 to 20004 at National-level data and information on thewww.ers.usda.gov/Data/Organic/index.htm#tables. organic potato industry in the United StatesPage 24 ATTRA Potatoes: Organic Production and Marketing
    • are presented in Table 4 on page 24. There be another steady outlet, though manyare no national statistics on prices and esti- restaurants can purchase organic prod-mates of costs of production are limited. ucts through specialized wholesale dis-The information presented here will draw tributors. Wholesale and direct marketingon a few sources from the United States, of organic potatoes to national specialtyCanada and Europe. retail grocery chains like Whole Foods Market, Inc., are other options. HereEmerging organic market again, such chains tend to access larger wholesale distributors rather than local orstructure regional farmers. Finally, as noted above,The organic potato market is not highly a relatively new market is emerging forstructured and is not currently in a situation food processing of organic potatoes bywith few buyers and a large number of sup- such national branded manufacturers aspliers. Demand for organic potatoes is grow- Cascadian Farms, Kettle Chips and Amy’sing, as is the general demand for all organic Kitchen. These food processors are devel-food. A lack of adequate supply to meet this oping new organic food lines often bygrowing demand has kept organic potato entering into specific contracts with indi-prices generally high. The organic potato W vidual specialized organic producers. hatevermarket may grow rapidly if larger proces- marketsors develop new organic product lines andsupply can meet the market demands in Marketing difference segmentthis emerging sector. Seth Pemsler of the Whatever market segment you enter, you enter, organicIdaho Potato Commission summed up the organic potato production, unlike conven- potato production,state of the expanding organic potato mar- tional production, offers a unique product. unlike conventionalket when he recently said, “the [organic] Not only are organic potato producers sell- production, offers amarket is there — the challenge is you have ing their distinct, ecologically sound sys- unique product.to be able to walk in and say ‘I can supply tem of production, they generally offeryou’”(Cavener, 2003). This statement was consumers a potato product of greaterin reference to a 2005 announcement by variety and fl avor. As noted in the storyinternational food manufacturer Frito-Lay below, Gene Thiel offers 20 different kindsthat the company would soon begin produc- of potatoes directly to consumers. Indeed,ing organic potato chips. Current options for one way for farmers to demand a highermarketing organic potatoes include direct, price and capture a greater market share inretail and the newly emerging organic pro- direct marketing systems is to offer some-cessing sector. thing unique and special. For instance, a purple Caribe potato variety might fi llMarket segments such a niche. Even the conventional potato industry is noting this desire by consum-Unlike the conventional potato industry, ers for new colors, flavors and textures andmost organic potatoes are probably sold these attributes may not remain unique tofresh and directly to consumers. Since the organic industry (Wilkens, 2006). Pro-farmers’ markets are expanding nationwide cessing potatoes led to greater uniformityand because a significant number of ven- of product to maintain product consistency.dors at these markets are organic, this is As more farmers enter the processing seg-one important outlet for organic potato pro- ment of the market, there may be someduction (USDA ERS, 2006). Since these diminishing of the flavor and color differ-potato producers are not highly specialized entiation. Although some processors suchin potato production, they can more eas- as Kettle Chips developed product linesily shift production annually as local and that promote color as a unique differentia-regional market prices change. tion, there may be implications for produc-Direct sales to retail markets are another tion since disease-resistant varieties don’tmarket segment. Sales to restaurants may exist in all colors and flavors.www.attra.ncat.org ATTRA Page 25
    • Price premiums and cost understood is the basis of the organic price premiums for specific products like potatoes of production and, more importantly, how and if premi- One of the motivations for transitioning to ums can be maintained. organic production is an expectation of a There appears to be a significant price price premium. Price premiums for most premium for organic potatoes based on organic food are significant and appear recent data on wholesale market prices as to be holding (USDA ERS, 2006). Less presented in Table 5. Profile of organic potato grower: Gene Thiel “It was hard going because those were the days before crite- Excerpt from Capital Press Agriculture News (July 2006) ria were established for organics certification, and we were Specializing in spuds, grower makes regular deliveries to competing with a lot of counterfeits,” Thiel said. “I spent so urban markets many hours giving depositions that it felt like I was on the JOSEPH, Ore. — Gene Thiel, aka Potatoman, has earned his place stand myself, but we managed to establish criteria to reward of prominence in the world of carefully grown organic produce. value. By 1974, Oregon Tilth came along, and since then con- ditions have steadily improved.” Born in Idaho Falls to a major potato-growing family, Thiel raises vegetables the way he thinks they ought to be raised and sells Today, in fields at the base of the Wallowa Mountains just them on a weekly basis to people who appreciate the quality. outside of the small town of Joseph, Thiel grows organic garlic, asparagus, beets, tomatoes, carrots, rat-tail radishes “Between parents, uncles and cousins, my family had 7,000 and 20 kinds of potatoes. Every Friday morning he drives acres of potatoes in Idaho during the years when there were west with about 6,000 pounds of harvest. 70,000 acres in production in the entire state,” Thiel said. “How- ever, when big business started telling us to how to grow them “It takes me a half a day to deliver produce from Hood River based on size and conformity rather than flavor and quality, to the east side of Portland,” Thiel said. “Then on Saturday I left the state in search of a quieter place and a quieter time. morning, I get up at 5 a.m. to set up the Portland Farmers In 1970, I moved to Troutdale, Ore., and started raising the first Market in the Park Blocks booth by 8 a.m. Our son, Patrick, certified organic carrots and potatoes in the West.” makes the rest of the deliveries for downtown and west Port- land while I run the market. Thiel, working with the secretary of state’s office, wrote the organic rules and set up the statute for growing organic produce. “After the market we both finish any delivering that still needs to be done and head for home. When the majority of our produce is still growing, we can make it home by about 10 p.m. on Saturday night, but during peak harvest season it is already Sunday morning before we get back to Joseph.” Thiel, who can tell you the attributes of each of the 20 kinds of potatoes he grows and the drawbacks of the ones he doesn’t grow, is often sought out for his expertise. He was recently featured in a book by Michael Ableman called Fields of Plenty, A Farmer’s Journey in Search of Real Food and the People Who Grow It (Chronicle Books) and is scheduled to appear along with local chefs at the Western Culinary Insti- tute in Portland. `“When my family started raising potatoes, they were all organic farmers,” Thiel said. “I’ve seen evolution to revo- lution, and I’m proud to be successfully farming land that has been organic since the Nez Perce were here. I started out with an old pickup and a shovel and built the business from there. I plant, harvest, pack, deliver and sell vegetables I consider to be the very best.” Information: Prairie Creek Farm or OTC Certified Organic Produce Gene Thiel in his organic potato fields in Joseph, Ore. Gene Thiel, P.O. Box 549, Joseph, OR 97846 Photo by and courtesy of Jan Jackson. (541) 432-2361, potatoman@eoni.comPage 26 ATTRA Potatoes: Organic Production and Marketing
    • Table 5. Wholesale organic and conventional potato prices for September 2006 Potato type Yukon Gold Red A price per lb for 50-lb sacks Market Org. Con. Org. Con. Philadelphia n/a $0.60 $0.70 $ 0.40 Boston n/a $0.56 $0.71 $ 0.54 San Francisco n/a $0.49 $0.86 $ 0.44 Seattle $0.67 $0.46 $0.67 $ 0.36 n/a- not available Source: Adapted from Rodale’s New Farm online Organic Price IndexFigure 1. Average farm-gate prices of surveys done by the Organic Farmingorganic and conventional ware potatoes Research Foundation in 1997 and 2001,(1998-2000; Euro per ton). U.S. organic farmers said median prices ofSource: Tamm L. et. al., 2004. organic potatoes appear to be comparable600 to those in 2006, as shown in Table 5. In 1997, the median wholesale price reported by the OFRF survey was 40 cents400 per pound. By 2001, it rose to 52 cents per pound. These are reported prices for 50- pound sacks of potatoes, as are the prices in Table 5. The OFRF data are from only four200 respondents in 1997 and six respondents in 2001 and the values are the median of the reported prices. The price data in OFRF’s report do not specify if these prices are wholesale or retail, though at the 50-pound DK F G NL NO CH UK sack size it is assumed to be a wholesale price. The data reported in Table 5 are from Farm-gate price for conventional potatoes (Euro/1000kg) actual reported prices at major wholesale Farm-gate price for organic potatoes (Euro/1000kg) markets in the respective cities.(DK-Denmark; F-France; G-Germany; NL-Netherlands; The two OFRF studies noted a median priceNO-Norway; CH-Switzerland; UK- United Kingdom). of $1 per pound in 1997 and a price of $1.51 per pound in 2001 for direct sales toAn excellent study, published in 2002, of consumers. However, the range in price inthe European organic potato industry indi- the direct consumer markets is quite widecates significant price premiums in Europe. in these two surveys with a low of 25 centsFigure 1 presents data from that report for per pound reported in 1997 and a high ofseven European countries. $5 per pound in 2001 (Waltz).As the graph indicates, farm-gate prices of There are at least three possible reasons fororganic potatoes in Europe, with the exception significant price premiums in organic potatoof France, were at least double conventional production. First and most obvious is thatprices during the 1998 to 2000 crop years. supply is limited and demand is high. This is often referred to as a sellers’ market. Sup-Finally, there seems to be evidence that ply and demand vary across the country,potato price premiums may hold over time by season of availability and the segmentin the United States. According to two of the market (wholesale, retail, direct) thewww.attra.ncat.org ATTRA Page 27
    • producer is selling to. For instance, the According to this study, the major dif- supply of organic potatoes for direct sales ferences in input costs for conventional in farmers’ markets may meet growing and organic potato production relate to demands in that market segment, but sup- increased labor, equipment, certification ply for wholesale distribution and process- and marketing costs. An expected cost dif- ing may not be sufficient relative to growing ference is the organic certification cost. On demand. This may be major source of the a 10-acre farm, for example, certification general upward pressure on prices. would be about $500 (in U.S. dollars). The Second, even though higher prices for other cost differences are not as simple to organic potatoes should invoke a supply understand. Higher labor costs are related response over time, there are high costs and to an assumption that weed control is more risks associated with transitioning to organic often done by hand in organic systems and potato production that dampen this response. that hand labor is more expensive than the Farmers already take on a high degree of use of synthetic herbicides, which are not risk and the adoption of a new system of available to organic producers. Higher labor production adds even more risk. Higher costs may also be due to the use of hired prices alone may not induce many farmers labor for harvesting. This may be less trueT he cost of to change production systems. Given growing for producers who moved to a more special- producing demand for organic potatoes, the supply may ized and larger volume of production where organic not catch up to demand very quickly. tillage equipment is available. However,potatoes may be hand labor crews are occasionally used Finally, the cost of producing organic pota- when potato plants become too large to cul-higher than toes may be higher than conventional potato tivate (BC-MAFF, 2002).conventional production. This means the price premiumpotato production. is really a reflection of that cost difference. The bottom line of this cost comparison The exposure to crop failure may be higher study is that organic potato production in when there are significant pest management British Columbia results in slightly lower problems associated with the production of yields, improved gross return on expenses a crop like potatoes. There are many stud- and higher production costs. But organic ies of the costs of conventional potato pro- potato production also results in a higher duction, but they reflect large-scale, highly net return per acre of production. In this specialized systems of production that are analysis, organic production provides about not easily compared to most organic sys- $81 (in U.S. dollars) more in per acre tems of potato production. return than a conventional farm of the same 10-acre size (BC-MAFF, 2002). There is Two comparative studies of no analysis of indirect expenses including organic and conventional potato depreciation, interest, insurance or eco- nomic profit. production costs A 2002 study by the British Columbia Min- A University of Wisconsin research team istry of Agriculture, Food and Fisheries did another study on input cost differences presents information on production cost dif- between organic and conventional potato ferences in conventional and organic potato production. The study included two commer- production systems. The study compares cial growers in Coloma, Wis., in 1990. While conventional and organic farms, each with the report does not provide detailed data, the 10 acres of potato production. The study one-year study found that organic potato yields does not use cost data from actual farms, per acre were 6 percent lower and overall but is based on reasonable approximations production costs were about $146 more per of costs made by government experts with acre. The researchers noted that prices would some farmer input. Still, there are several have to be close to double conventional prices to results from the study that can help deter- make up for costs and yield losses from organic mine production cost differences. production.Page 28 ATTRA Potatoes: Organic Production and Marketing
    • In summary, the price premium for of development will simply follow the pat-organic potato production comes mostly tern of the conventional food market. Howfrom an imbalance of supply relative to the infant organic processed potato industrydemand. The general difficulties and develops in the future will depend on a fewhigh risk associated with transitioning to emerging trends.organic production have limited a supply If major food manufacturers continueresponse to this high demand over the to tap the rising demand for organiclast few years. Costs of production may food, more farmers will likely special-be higher for organic potatoes, but there ize in organic potato production to meetare not enough data and careful analy- those processor needs. This is a positivesis of these costs for different scales, outcome in the sense that more potato pro-locations and systems of production to duction will be done organically. In generalknow for sure. Higher costs and higher it has positive environmental and energy-sav-price premiums may be due to the lack ing implications for society as a whole. Theof appropriate-scale machinery to replace downside is that the organic potato industryhigh labor costs associated with small- to may develop the same kind of concentratedmedium-scale organic potato production. structure as the conventional potato indus- TFinally, it may be that the processing and he price try, with ultimate loss of price premiums,packing facilities available to organic tight profit margins and fewer but larger premiumpotato producers are inadequate, forcing producers. There does appear to be some for organicorganic producers to invest more in pack- growth of larger and specialized organic potato productioning equipment than conventional growers. potato farmers interested in tapping these comes mostly fromThis certainly increases costs. processed food markets (Cavener, 2003). an imbalance of The ongoing expansion of local direct- supply relative toEstimating costs and profitability market opportunities, including farmers’ demand.for organic potato production markets and intrastate sales of local foodEnterprise budgets are an important tool through community-supported agriculturefor planning and on-going farm fi nancial and schools, prisons, hospitals and othermanagement, but budgets only represent institutional markets, may provide for aone set of many possible cultural and man- more diversified production capacity includ-agement practices and do not account for ing organic potatoes. There could be a movegeographic differences. Given that so few to create more regionally specific and spe-studies of enterprise budgets for organic cialized production of organic potatoes tiedpotato production are available, it is prob- to regionally and farmer-owned cooperativeably best to either develop your own budget processing and storage facilities.or modify conventional potato production The future of the organic potato mar-enterprise budgets. Conventional enterprise ket, like organic food production, involvesbudgets for potatoes are available for many issues beyond the simple capacity to pro-states from the Ag Risk Education Library duce food organically. More and more, theat www.agrisk.umn.edu. The budgets are challenge of organic food production willnot all recent, but are good starting points. be addressing issues around the greaterThe University of Idaho does a good job socioeconomic implications of marketproviding conventional potato production structure and general control in the foodbudgets. The budgets are available at www. system. Carolyn Christman and Michaelag.uidaho.edu/aers/crop_EB_05.htm. Sligh addressed some of these issues in a 2003 publication entitled WhoThe emerging processed organic Owns Organic?potato industry “The question debated now is how to both protect and expand the value of organicThose who watch the rapid development of food. It is especially important to considerorganic food markets fear that the pattern whether the value rests solely in a narrowwww.attra.ncat.org ATTRA Page 29
    • agricultural framework or could be based Special thanks to our reviewers in a broad ideological framework as being good for the Earth, the water, the air, the Brian A. Charlton, assistant professor of crop- animals, the workers, the farmers, the con- ping systems and potato research at Oregon State sumers and their communities”(Christman University; and Jennifer Miller of the Northwest and Sligh, 2003). Coalition for Alternatives to Pesticides. Profile of organic potato grower: Mike Heath, grains, vetch, buckwheat and sunflowers. He supplements his M&M Heath Farms homegrown beneficial insects with purchases of ladybugs from Peaceful Valley Farm Supply in Grass Valley, Calif. Mike Heath of Buhl, Idaho, plants from 20 to 100 acres of organic potatoes a year. In recent years he has planted For weed control, Heath does blind cultivation, or cultivating between 45 and 50 acres per year. He grows about 10 dif- before the crop emerges, on part of the acreage. He also does ferent varieties, including reds, yellows, russets, fingerlings conservation tilling with a chisel plow. Noxious weeds cause and purples. He also grows other crops in addition to pota- Health’s biggest headaches. Morning glory, which might be toes, including some vegetables, and raises livestock. a result of his crop rotations, is his biggest problem. Heath is considering some deep chiseling in the fall for morning glory Seed sources control, and is considering grazing with sheep or goats. Idaho doesn’t have any organic seed growers, so Heath uses Heath has very few storage disease problems. Early Yukons untreated conventional seed pieces. He buys some and others occasionally have a few problems with rot, mainly caused by he cuts and prepares himself. His commercial source comes the heat in the field at harvest in August. out of Ashton, Idaho, and is shipped in 2,000-pound totes of seed pieces. These seed pieces are pre-treated with fir bark Harvesting flour, which helps suberize them. The fir bark flour treatment is Prior to harvest, Heath uses a flail mower to chop down the what growers used prior to the advent of modern fungicides. potato plants. Timing is important. When Heath is trying to Heath will generally plant when he receives the seed pieces, hit an early market and farmers’ markets, he uses a wind- but if the weather is not good he will hold these seed pieces rower to loosen the ground and then picks up the potatoes for up to three weeks without any problems. by hand. For the bulk market, he uses a windrower and a two- row harvester simultaneously, so he works four rows at once. Rotation He always washes the fresh pack immediately. Heath uses a seven-year crop rotation: three years of alfalfa, one year of row crop, one year of grain, one year of row crop, Heath generally harvests 400 50-pound sacks per acre follow- one year of grain and then back to three years of alfalfa. The ing alfalfa ground. He usually budgets for 300 sacks, noting alfalfa is sold to local dairies and has the added benefits of that in this part of the county, that’s OK, but most conven- weed control and building up the soil. Dry beans, squash tional growers would shoot for from 350 to 400 sacks. Colored and potatoes are some of the row crops Heath grows. He potatoes, which are smaller, will give a yield of around 250 to also grows feed corn, depending on the market. 275 sacks per acre. The only cover crop Heath has used so far is alfalfa. He notes Heath has noticed some real improvement in soil quality, espe- that water is an important consideration for a cover crop. cially on the ground that has been under organic production the longest. He notes that on any soil test measure, his ground Pest management will show a higher functioning soil than his neighbors with Potato beetles have become more of a problem pest in recent land in conventional production. years. In early spring Heath will try to pick adult potato bee- tles prior to egg laying. Heath also uses Entrust, an organically Specialized equipment approved formulation of Spinosad that is very expensive, but Heath has an old four-row John Deer spike-type planter that also effective. He buys Entrust as a powder in 12-pound box he uses for really small potato pieces. He also has a Logan for about $4,200 and uses 2 ounces per acre. Heath shares four-row cup-type planter. Heath observed that now four- the box with two other growers, which helps alleviate some row planters are very cheap because growers are switching of the expense. In 2006, he sprayed twice for potato beetles. to six-row planters. The cost of material per application is just less than $44 per Marketing acre, or $21.88 per ounce. Half of Heath’s crop is processed and half is fresh-packed. He In past years, Heath notes that he hasn’t had enough cold has his own packing shed, and shares a bag that is labeled as weather to kill volunteer potatoes in rotated crops. That can “Organically Grown in Idaho” through the Idaho Organic Coop- create a minor pest haven, especially for disease. Although Idaho erative. Heath and other potato growers market this product occasionally has late blight, Heath has never seen it in his fields. to grocery stores and CSAs in the region. A new company is To promote potato plant health, Heath uses a compost tea deliv- setting up a packing line dedicated to organics, so that might ered through his irrigation system. He doesn’t have any prob- provide some more options. Heath noted that he does not sell lems with aphids and thinks the pests are controlled by a good Russets by fresh pack. Heath receives about $10.50 per cwt on population of beneficial insects. Heath promotes beneficials by a contract for processing. He always keeps some potatoes in planting the field edges with annuals, such as sunflowers, peas, stock for local sale and receives about $40 to $50 per cwt.Page 30 ATTRA Potatoes: Organic Production and Marketing
    • References Christman, Carolyn and Michael Sligh. 2003. Who Owns Organic: The Global Status, Prospects andBASF Canada. 2005. Disease Guide, Challenges of a Changing Organic Market. RAFI-USA.Rhizoctonia (Black Scurf). www.agsolutions.ca/basf/ Frazier, Mary Jo, et al. 2004. Organic and Alternativeagprocan/agsolutions/WebASPests.nsf/DiseaseEast.htm Methods for Potato Sprout Control in Storage. UniversityBeagle-Ristaino, J.E. and G.C. Papavizas. 1985. of Idaho Extension.Biological control of Rhizoctonia stem canker and Gallant, E.R. 1998. Effects of pest and soil managementblack scurf of potato. Phytopathology. May 1985. systems on weed dynamics in potato. Weed sciencev. 75 (5) p. 560-564. Mar/Apr 1998. v. 46 (2) p. 238-248.Bennett, K., E. C. Burkness and W. D. Hutchison. Ghidiu, G.M., G.C. Hamilton, and G.W. Kirfman.2007. VegEdge: Potato Leaf Hopper. University of 1994. Bacillus thuringiensis ssp. tenebrionis spraysMinnesota Extension Service. University of Minnesota. affect hatching of Colorado potato beetle (Coleoptera:Berry, R.E., J. Liu, and G. Reed. 1997. Comparison Chrysomelidae) eggs and subsequent larval dispersal.of endemic and exotic entomopathogenic nematode Journal of economic entomology. Oct 1994. v. 87 (5)species for control of Colorado potato beetle (Coleop- p. 1298-1301.tera: Chrysomelidae). Journal of economic entomology. Grubinger, Vernon. August 2005. Growing OrganicDec 1997. v. 90 (6) p. 1528-1533. Potatoes. The Vermont Vegetable and Berry ProgramBradley, B. W and F. Ellis. 1992. The Organic Fact Sheets. University of Vermont Extension. www.Gardener’s Handbook of Natural Insect and Disease uvm.edu/vtvegandberry/factsheets/organicpotato.htmlControl: A Complete Problem-Solving Guide. Rodale Hollingsworth, Craig S. (ed.), et al. 1986. PotatoPress. Emmaus, PA. Production in the Northeast: A Guide to Integrated Pest Management. Cooperative Extension, UniversityBrust, G.E. 1994. Natural enemies in straw-mulch of Massachusetts, Amherst, MA.reduce Colorado potato beetle populations anddamage in potato. Biological Control. Vol. 4, No. 2. p. Howell, C.R. 1987. Relevance of mycoparasitism in163–169. the biological control of Rhizoctonia solani by Glio- cladium virens. Phytopathology. Phytopathology JulyBritish Columbia Ministry of Agriculture, Food, 1987. v. 77 (7) p. 992-994.and Forestry (BC-MAFF). 2002. Transition toCertified Organic Potato Production-10 Acre Farm. Hutsinger, Kate. 1995. Sustainable potato produc-Planning for Profit Series. tion. Northwest Coalition for Alternatives to Pesticideswww.agf.gov.bc.ca/busmgmt/budgets/budget_pdf/ Newsletter. Vol. 15, No. 2, Summer 1995, p. 4, 5.specialty_organic/transitional_organic_potato.pdf Jager, G. and H. Velvis. 1986. Biological control of Rhi-Caldwell, Brian. 1999. Production and Marketing of zoctonia solani on potatoes by antagonists. NetherlandsOrganic Potatoes in New York. South Central NY Journal of Plant Pathology. v. 92 (5) p. 231-238.Agricultural Team. Cornell Cooperative Extension. Jones, Richard. 1999. Bad news for beetles.Cavener, Lorraine. 2003. Opportunities Available to American Vegetable Grower. February. p. 12, 14.Grow Organic Potatoes. Organic Trade Association King, Carol. Personal communication.Web site. www.ota.com/organic_potatoes.html NOFA-NY Certified Organic, LLCCharlton, Brian. 2008. Personal communication. 840 Upper Front StreetDept. of Crop & Soil Science. Oregon State University. Binghamton, NY 13905Klamath Basin Research & Extension Center (607) 724-98513328 Vandenberg Rd. or (607) 724-9853 FAX6941 Washburn Way www.nofany.orgKlamath Falls, OR 97603 Lahkim, L. 1999. Biological Control of Early Blight in Tomatoes. Acta Hort. (ISHS) 487:271-274.Ceresini, P. 1998. North Carolina State University,Pathogen Profi le. www.cals.ncsu.edu/course/pp728/ Larkin, R.P. and M.M. Talbot. 2002. Suppression ofRhizoc tonia/Rhizoctonia.html rhizoctonia disease of potato by biological control andwww.attra.ncat.org ATTRA Page 31
    • a ryegrass rotation. National American Phytopathology National Organic Program (NOP). 2006.Meetings. 92: S80. National Organic Program Regulations andLeach, S. S. and L. P. Specht. 1987. Effects of Crop Guidelines. www.ams.usda.gov/nop/NOP/Rotation on Rhizoctonia Disease of White Potato. NOPhome.htmlPlant Disease. V. 71:433-437. The American Olkowski, W., N. Saiki, S. Daar. 1992.Phytopathological Society. IPM options for Colorado potato beetle.Levins, Richard. 2005. Market Power for Farmers: IPM Practitioner 14:1-21.What It Is, How to Get It, How to Use It. Institute for Padgham, Jody. 2002. IGL Farms:Rural America. Certified Organic Potatoes. The OrganicLewis, J.A. and G. C. Papavizas. 1987. Application Broadcaster. Midwest Organic andof Trichoderma and Gliocladium in alginate pellets for Sustainable Education Service.control of Rhizoctonia damping-off. Plant pathology. Papavizas, G.C. 1987. Reduction ofDec 1987. v. 36 (4) p. 438-446. inoculum of Rhizoctonia solani in soil byMcGuire, Andy. 2003. Using Green Manures in germlings of Trichoderma hamatum. SoilPotato Cropping Systems. Washington State University biology and biochemistry. Soil BiolCooperative Extension Publication # EB1951E. Biochem 1987. v. 19 (2) p. 195-201.Metcalf, R. and W.P Flint. 1962. Destructive and Patterson, et al. 2005. Idaho State cropsuseful insects: their habits and control. 4th ed. enterprise budgets for 2005. University ofMcGraw-Hill. New York, NY. Idaho. www.ag.uidaho.edu/aers/crop_EB_Miller, Jennifer, Ronda Hirnyck, Lisa Downey- 05.htmBlecker; Editor: Diane Clarke. 2008. Perry, Keith. 2002. New York CertifiedPest Management Strategic Plan for Organic Potato Seed Potato Variety Descriptions.Production in the West. Summary of workshops held New York Seed Improvement Project.on February 16, 2006 Buhl, Idaho, and January 9, Downloaded November 2006.2008 Portland, Oregon. http://seedpotato.newyork.cornell.edu/variety.htmlMirabelli, C., Colla, G., Fiorillo, A., Cardarelli, M., Pleasant, Barbara. 2007. Royal PotatoesRouphael, Y. and Paolini, R. 2005. The Effect Of that Beat Bugs. Mother Earth News.Mechanical Weed Control Technique And Irrigation October/ November 2007.Method On Yield, Tuber Quality And Weed Suppres-sion In Organic Potato. Acta Hort. (ISHS) 684:127-134 Porter, Gregory. 2006. Personalwww.actahort.org/books/684/684_17.htm communication. University of Maine.Moreau, T., P. Warman, and J. Hoyle. 2006. An Porter, Gregory. 2002. Soil Amendment andevaluation of Companion Planting and Botanical Crop Rotation Effects on Productivity andExtracts as Alternative Pest Controls for the Colorado Soil Properties within Potato ProductionPotato Beetle. Biological Agriculture and Horticulture. Systems. Sustainable Agriculture ResearchVol. 23, p. 351-370. and Extension Project Report. ProjectMosely, A. 2004. Potato Storage and Processing. Number: LNE98-103.Oregon State University. Potato Information Exchange. Rowe, R.C., S.A. Miller, and R.M. Reed.Moyer, D.D. 1992. Fabrication and Operation of a 1995. The Ohio State University ExtensionPropane Flamer for Colorado Potato Beetle Control. Fact Sheet, Rhizoctonia Stem and StolonCornell Cooperative Extension- Suffolk County, Canker of Potato. www.ohioline.osu.edu/Riverhead, New York, p. 1-6. hyg-fact/3000/3108.htmlNational Research Council. 1992. Neem: A Tree For Ruttle, Jack. 1989. Speedy spuds beatSolving Global Problems. National Academy Press, beatles. National Gardening. April.Washington, D.C. p. 55-57, 76-77.Page 32 ATTRA Potatoes: Organic Production and Marketing
    • Sideman, Eric and Steven Johnson. 2006. Producing Certified Organic Potatoes Production-NorthPotatoes Organically. The Natural Farmer. Fall 2006. Okanagan 10 Acre FarmStevenson, W.R. 1993. Early Blight and Late Blight. www.agf.gov.bc.ca/busmgmt/budgets/budget_pdf/spe-In: Randell C. Rowe (ed.) Potato Health Management. cialty_organic/transitional_organic_potato.pdf.APS Press, St. Paul, MN. Duvall, Jean. 1997. Cover Cropping in Potatoes.Stevenson, et al. 2007. Fungicide Spray Programs for Ecological Agriculture Projects, McGill UniversityDefender, A New Potato Cultivar with Resistance to (Macdonald Campus). Ste-Anne-de-Bellevue, QC,Late Blight and Early Blight. Plant Disease. October H9X 3V9 Canada2007, Volume 91, Number 10. p. 1327-1336. http://eap.mcgill.ca/Publications/EAP71.htm.Strand, Larry. 2006. Integrated Pest Management for OSPUD Oregon State Organic Potato Project.Potatoes in the Western United States, 2nd Ed. Univer- http://ospud.orgsity of California, Agriculture and Natural Resources. This is a participatory project with organic potato farmers and university scientists. The farm-basedTamm L. et al. (2004): Assessment of the socio- research is published regularly on their Web site.economic impact of late blight and state-of-the-artmanagement in European organic potato productionsystems. FiBL, Frick, 106pp. ContactsUSDA Economic Research Service. 2005. Potato Organic Potato GrowersFacts: www.ers.usda.gov/Briefing/Potatoes/potatofacts.htm Tom HamiltonUSDA Economic Research Service. 2006. Organic An organic potato grower and marketing coordina-Produce, Price Premiums and Eco-labeling, U. S. tor for a Colorado organic potato grower cooperative.Farmers Markets. Hamilton can share production practice information.Vales, Isabel. 2004. Potato Information Exchange 23242 Highway 371Web Site. Storage and Processing. Oregon State La Jara, CO 81140University Extension. http://oregonstate.edu/potatoes/ (719) 274-5998storproc.htm Jim and Megan GerritsenWaltz, E. 2004. Fourth National Organic Farmers’ Well-known organic potato growers who produceSurvey. OFRF. www.OFRF.org certified seed potatoes in Maine. Wood Prairie FarmWaltz, E. 1999. Third Biennial National Organic R.F.D. #1, Box 164Farmers’ Survey. OFRF. www.OFRF.org Bridgewater, ME 04735Weisz, R., Smilowitz, L., and B. Christ. 1994. Igl FarmsDistance, rotation, and border crops affect Colorado W9689 Cherry Roadpotato beetle (Coleoptera: Chrysomelidae) colonization Antigo, WI 54409and population density and early blight (Alternaria (715) 627-7888solani) severity in rotated potato fields. Journal of eco- www.sustainusa.org/familyfarmed/profile_iglfarms.htmlnomic entomology. June 1994. v. 87 (3), p. 723-729.Westerdahl, B.B. 2007. University of California Pest Woody DeryckxManagement Guidelines: Potato Nematodes. UC A consultant to organic potato growers in theANR Publication 3463. www.ipm.ucdavis.edu/PMG/ Northwest. Deryckx also has a farm of his ownr607200111.html in southern Oregon. Bentwood Organic FarmWilkens, Dave. 2006. Specialty Potatoes Ready to PO Box 451Shine. Capital Press, 2006. Malin, OR 97632 (541) 891-1048Further resources wderyckx@cvc.netOnline University contactsMinistry of Agriculture, Food & Fisheries British Dr. Gregory PorterColumbia, 2002. Planning for Profit: Transition to Department of Plant and Soil Sciencewww.attra.ncat.org ATTRA Page 33
    • Deering HallUniversity of Maine Products for organic potato pest managementOrono, ME 04469 Colorado Potato Beetle(207) 581-2935 Spinosad Dow AgroSciences LLCBrian Charlton 9330 Zionsville RoadDepartment of Crop and Soil Science Indianapolis, IN 46268Oregon State University (317) 337-3000Klamath Basin Research and Extension Center Mycogen Corporation3328 Vandenberg Rd. or 5451 Oberlin Drive6941 Washburn Way San Diego, CA 92019Klamath Falls, OR 97603 (619) 453-8030(541) 883-7131 or (541) 883-4590 Mycotrolbrian.a.charlton@oregonstate.edu Laverlam International 117 South Parkmont Butte, MT 59701Specialized potato equipment (406) 782-2386suppliers (406) 782-9912 (FAX) www.laverlamintl.comUS Small Farm5428 Road 57 RhizoctoniaTorrington, WY 82240 Trichoderma viridi1-888-522-1554 Manufacturer Iinformation:(307) 534-1818 Binab Bio-Innovation AB Florettgatan 5ussmallfarm@yahoo.com Helsingborg SE-254 67Market Farm Implement Sweden257 Fawn Hollow Road 46-42163704 46-42162497 (FAX)Friedens, PA 15541 www.algonet.se/~binab(814) 443-1931 info@binab.comwww.marketfarm.com Trichoderma virens (formerly Gliocladium virens) Manufacturer Information:Publications Certis USA, LLC 9145 Guilford Road, Suite 175Pest management Columbia, MD 21046Al-Khatib, K., and R. Boydston. 1994. Weed con- USA 1-800 -847-5620 (toll-free)trol with rapeseed and white mustard green manure. www.certisusa.comPacific Northwest Sustainable Agriculture. April. p. 4. Insect biological controlsGrossman. J. 1991. Potato disease transmission. See ATTRA Publication Integrated Pest ManagementOrganic potatoes in Wisconsin. The IPM Practitioner. for Greenhouse Crops for a comprehensive listing ofMay/June. p. 16-17. Biological Control Suppliers.Klassen, Parry. 1988. Biopesticide battles Coloradopotato beetle. American Vegetable Grower.March. p. 40. Ragsdale, D. T. Radcliffe, and C. DiFonzo. 1994. Crop borders — a way to prevent spread of PVY.Miller, Jennifer; Ronda Hirnyck, Lisa Downey-Blecker; Valley Potato Grower. July. p. 30-33.Editor: Diane Clarke. 2008. Pest ManagementStrategic Plan for Organic Potato Production in the West. Hollingsworth, Craig S. (ed.), et al. 1986. Potato Pro-Contact: Ronda Hirnyck at (208) 364-4046 or duction in the Northeast: A Guide to Integrated Pestrhirnyck@uidaho.edu or Jennifer Miller at (208) Management. Cooperative Extension, University of850-6504 or jmiller@pesticide.org for a copy. Massachusetts, Amherst, MA. Available through:Page 34 ATTRA Potatoes: Organic Production and Marketing
    • University of Massachusetts Available through:Cooperative Extension Service The American Phytopathological SocietyAmherst, MA 01003 3340 Pilot Knob Road(413) 545-6538 St. Paul, MN 55121-209IPM Practitioner feature on Colorado Potato BeetleIPM: Olkowski, W., N. Saiki, S. Daar. 1992. IPM Storage and processingoptions for Colorado potato beetle. IPM Practitioner Potato Storage and Processing. Potato Information14:1-21. Available at Bio-integral Resource Center Exchange Web Site. Oregon State University.PO Box 7414 http://oregonstate.edu/potatoesBerkeley, CA 94707(510) 524-2567 Frazier, Mary Jo, et al. 2004. Organic and Alternative Methods for Potato Sprout Control in Storage. University of Idaho Extension.Cover crops and rotations http://info.ag.uidaho.edu/pdf/CIS/CIS1120.pdfDuvall, Jean. 1997. Cover Cropping in Potatoes.Ecological Agriculture Projects, McGill University. Marketing and business managementSte-Anne-de-Bellevue, QC, H9X3V9 Canada. EAPPublication #71. http://eap.agrenv.mcgill.ca/ Hofstetter, B. 1993. Specialty spuds. The New Farm.Publications/EAP71.htm March-April. p. 35-37. www.pvmi.org/Storage/General/ Specialty%20Spuds%20-%20Spudman%204-07.pdfSustainable potato production British Columbia Ministry of Agriculture, Food, andCummings, T., R.E. Thornton, and R.T. Schotzko. Forestry. 2002. Transition to Certified Organic Potato1994. Comparison of conventional and alternative Production-10 Acre Farm. Planning for Profit Series.potato systems. Pacific Northwest Sustainable Agricul- www.agf.gov.bc.ca/busmgmt/budgets/budget_pdf/spe-ture. June. p. 6. cialty_organic/transitional_organic_potato.pdfHansen, C.M. 1969. Desiccating potato vines withflame. p. 37-38. In: Proceedings of the Sixth Annual The ATTRA project is operated by the NationalSymposium on Use of Flame in Agriculture. Spon- Center for Appropriate Technology under a grant from thesored by the Natural Gas Processors Association. Rural Business-Cooperative Service, U.S. Department ofRowe, R.C. (ed.). 1993. Potato Health Management. APA Agriculture. These organizations do not recommend orPress, St. Paul, Minnesota. 178 p. endorse products, companies, or individuals.www.attra.ncat.org ATTRA Page 35
    • Potatoes: Organic Production and Marketing By Rex Dufour, Tammy Hinman and Jeff Schahczenski NCAT Agriculture Specialists © 2008 NCAT Holly Michels, Editor Amy Smith, Production This publication is available on the Web at: www.attra.ncat.org/attra-pub/potatoes.html or www.attra.ncat.org/attra-pub/PDF/potatoes.pdf IP337 Slot 335 Version 062909Page 36 ATTRA