Effective weed control measures <ul><li>Never allow any weeds to mature and set seed </li></ul><ul><li>Keep weeds and grasses from maturing and setting seed around the outside of your high tunnel </li></ul><ul><li>Use weed barriers (mulches) when practical </li></ul><ul><li>Utilize strategies that eliminate or reduce the amount of cultivation needed to keep the crop weed free </li></ul><ul><li>Before weeds become a problem, make the time to cultivate when they are young, or better yet, before they even emerge </li></ul>
Striped Cucumber Beetle ( Acalymma vittatum ) Striped cucumber beetles (SCB) are 1/4 inch long with black and yellow longitudinal stripes and black head and abdomen View photo 2.3 . In the Northeast, they pass the winter as adults sheltered under plant debris and become active in the spring as soon as cucurbits appear. The overwintered generation lives until August and feeds on all plant parts. Small seedlings are very susceptible and are often killed. Once the plants attain 4-5 true leaves, they are more tolerant of striped cucumber beetle feeding; however, disease transmission is still important (see below). The beetles lay their eggs at the base of cucurbit plants. These hatch into larvae, which feed below ground on the roots and crowns of the plants. The new generation of adults emerges in July, and can cause feeding damage to pumpkins and other cucurbit fruit. They will overwinter and then feed on next year’s crop.
Green Peach Aphid Myzus persicae (Sulzer), Aphididae, HEMIPTERA BIOLOGY Distribution - The green peach aphid is a cosmopolitan species. Host Plants - The green peach aphid infests a wide range of plants. Some important hosts include cabbage and related cole crops, dandelion, endive, mustard greens, parsley, turnip, tomato, tobacco, potato, spinach, pepper, beet, celery, lettuce, and chard. Damage - Green peach aphids extract sap from plants and excrete a sweet sticky substance known as honeydew. Black sooty mold grows on honeydew and, though not directly harming the plants, may block out sufficient light to reduce yield. Weakened plants become susceptible to secondary disease and may be inoculated with viruses carried by aphids. Among the virus diseases transmitted by green peach aphids are potato leaf roll, potato virus Y, beet mosaic, beet yellows, and lettuce mosaic. Life History - Adults pass the winter on greens and wild hosts such as cabbage, collards, turnip, wild mustard, and dock. Winged forms migrate to other hosts in late spring. During these migratory flights, aphids may spread virus diseases from infected volunteer plants and weeds to healthy crop plants. Movement between host plants continues through summer and fall. In southern states, the aphids are nearly all females. Successive generations of females, mainly wingless, are produced throughout the year. Winged migrants develop whenever overcrowding occurs or food becomes scarce. This type of development (all females, no males or eggs) occur as far north as Tennessee and Maryland. Many generations are produced each year.
<ul><li>So, why do aphids like my high tunnel & why are they such a problem?! </li></ul><ul><li>Aphids like humidity </li></ul><ul><li>Dense plantings provide plenty of food & cover </li></ul><ul><li>They reproduce at lower temperatures than predators </li></ul><ul><li>Poly covering excludes rainfall, so insects aren’t disturbed. </li></ul><ul><li>Parasitoids can cause a worse problem on leafy greens </li></ul>
Best chance at Aphid control <ul><li>Early detection through scouting </li></ul><ul><li>Insecticidal soap spray (underside of leaves) </li></ul><ul><li>Neem based products </li></ul><ul><li>Trap crops ( they seem to like mustard!) </li></ul><ul><li>Remove infested vegetation </li></ul><ul><li>Overhead irrigation (is this a plus or a minus?) </li></ul><ul><li>Lady Beetle release* </li></ul><ul><li>Lacewings release* </li></ul><ul><li>*effective only if </li></ul><ul><li>done in summer! </li></ul>The worst thing you can do is ignore them!
<ul><li>Fungal diseases seem to be the most prevalent </li></ul><ul><li>Vent your high tunnel early in the day to remove moist air. </li></ul><ul><li>Vent even when cold out </li></ul><ul><li>Use tall roll-up sides to move air over tall plants </li></ul><ul><li>Have adequate spacing between plants to allow for good air flow </li></ul><ul><li>Scout for disease & rogue out (remove) sickly plants! </li></ul><ul><li>Be cautious – it’s easy to transmit disease between plants </li></ul><ul><li>Keep your soil biologically alive through the use of compost </li></ul>
Biofumigation Certain Brassica cover crops, as well as mustard seed meal, contain high concentrations of isothiocyanates (ITCs) – derived from the degradation of glucosinolates (what gives them the pungent taste). The seed meal is also a significant source of nitrogen and other nutrients. When incorporated into the soil ITCs act as an effective biofumigant, reducing populations of pathogenic fungal species (Sclerotium, Rhizoctonia, and Phytium), nematodes, weeds, and certain insect species. UT/TSU 2003 In addition, the residues add important organic matter for soil building.
Why are GSL's Important? <ul><li>Glucosinolates hydrolize to form biocidal compounds </li></ul><ul><li>These include: </li></ul><ul><ul><li>Isothiocyanates </li></ul></ul><ul><ul><li>Oxazolidine-2-thiones </li></ul></ul><ul><ul><li>Nitriles </li></ul></ul><ul><ul><li>Epithionitriles </li></ul></ul><ul><ul><li>Thiocyanates </li></ul></ul><ul><ul><ul><li>(Halkier and Gershenzon, 2006) </li></ul></ul></ul><ul><li>Potential to suppress pathogens </li></ul>www.wikimedia.org Slide by Craig Rothrock, University of Arkansas, Fayetteville, AR
Influence of brassica cover crops on soil microbial populations gurosiksberryplantation.com Slide by C. Rothrock, U of A, Fayetteville, AR Table 7. Soil populations of select microbial groups for different preplant strawberry treatments, Hope. 1 Strawberry transplant Treatment Bacteria (x 10 7 ) Fungi (x 10 4 ) Actinomycetes (x 10 6 ) Control 1.9 b 6.5 a 10.0 b Brassica 2.9 b 18.5 a 17.0 a Brassica +Solarization 9.8 a 19.4 a 19.5 a Solarization 2.9 b 12.3 a 10.4 b Mustard seed meal 8.0 a 31.0 a 14.4 ab
<ul><li>1) Brassica cover crops may be a valuable and profitable addition to a high tunnel production system because they can suppress soilborne pathogens. </li></ul><ul><li>2) Brassica crop selection is less important than rate of application. About 1/2 pound per 1000 square feet for Pacific Gold. </li></ul><ul><li>3) Duration of suppression by brassica cover crops may extend beyond biofumigation effects by changes in the soil microflora. </li></ul>Brassica research summary from U of A, Fayetteville, AR ~ Dr. Craig Rothrock
Pacific Gold Mustard Grow in place, mow, turn under and seal.
To obtain a sample of Pacific Gold or Ida Gold Mustard Please contact Kim Davidson E-mail: [email_address] Phone: (509) 487-0755