Squash Bug and Squash Vine Borer: Organic Controls

1. Squash Bug and Squash Vine
ATTRA Borer: Organic Controls
A Publication of ATTRA - National Sustainable Agriculture Information Service • 1-800-346-9140 • www.attra.ncat.org
By Katherine L. Adam Squash bug and squash vine borer are major pests among cucurbits. This publication addresses organic
NCAT Agriculture control methods for these pests. The life cycles and characteristics of each pest are presented. Various
Specialist levels and types of organically sanctioned controls are discussed. Row covers, cultural methods, and
©2006 NCAT physical practices are also covered. Experimental controls, biological controls, and alternative insecti-
cides are also discussed and a case study is presented. A list of references follows the narrative.
Contents
Introduction ..................... 1
Life Cycle and
Characteristics:
Squash Bug....................... 2
Life Cycle and
Characteristics: Squash
Vine Borer ......................... 2
Planning for Control ..... 2
Levels of Control in
Certified Organic
Production ........................ 3
Systems-based
practices (level 1)............ 3
Mechanical and physical Squash bug. Squash vine borer.
practices (level 2) ........... 3 ©Bruce Marlin 2003 ©Bruce Marlin 2004.
Material (level 3) ............. 4 http://cirrusimage.com http://cirrusimage.com
Row Covers ...................... 5
Host Preference and
Genetic Resistance ....... 5
Introduction and die back. Certain species and variet-
S
Other Cultural and
Physical Controls ............ 7 quash bug and squash vine borer are ies of pumpkins, watermelons, and squash
Experimental, creative among a trio of serious cucurbit pests. are more susceptible than others. Plants
approaches .................... 8 Striped cucumber beetle is another. are most susceptible to damage when they
Recommended For control measures for striped cucumber
strategies ........................... 8
are small.
beetle on squashes in organic production, see
Biological Control ......... 9
the ATTRA publication Cucumber Beetles: Squash vine borer (Melittia satyriniformis
Kaolin Clay ...................... 10
Organic and Biorational IPM. Lepidoptera: Ageiriidae) is a pest in the
Alternative eastern half of the United States. Squash
Insecticides .................... 10 Squash bug (Anasa tristis Hemiptera: Core- vine borer is native to a large area from
References ...................... 10 idae) is the most serious pest of squash
east of the Rocky Mountains to the Atlantic
and pumpkins in the U.S. and is a poten-
ATTRA—National Sustainable Coast and from Canada to South America.
Agriculture Information Service tial problem for all cucurbits. Squash bugs
is managed by the National Cen-
(found only in the Western Hemisphere) (2) In the U.S. it can cause significant crop
ter for Appropriate Technology
(NCAT) and is funded under a range widely from the east to west coasts losses east of a line that roughly parallels
grant from the United States
and north to south from Canada to South Interstate 35. (3) The larvae of squash vine
Department of Agriculture’s
Rural Business-Cooperative Ser- America. (1) Adults and nymphs of squash borer damage plants by destroying tissue
vice. Visit the NCAT Web site
(www.ncat.org/agri. bugs damage plants by sucking plant juices in the stem and causing anything beyond
html) for more informa- from the leaves. Further, they inject a toxin that point to die—either the whole plant or
tion on our sustainable
agriculture projects. ���� that causes the plants to wilt, blacken, a runner.

2. Some of the same controls have recently Life Cycle and Characteristics:
been found to work well for both pests in
commercial-scale organic production, even Squash Vine Borer
though the two pests come from different Squash vine borers overwinter as larvae
orders/families of insects, and their dif- or pupae in the soil. Adult moths emerge
ferent developmental stages do damage in the spring and deposit eggs on a host
to different parts of the squash plants. (4, plant. Disk-shaped, dark-reddish-brown
5) Preventive management practices con- eggs are laid singly on the plant near the
base. (7) After hatching, the larvae pen-
sist of destroying crop residues and debris
etrate the plant stem and burrow toward
that provide shelter for overwintering adults
the base. An individual adult can lay from
and excluding entry using a row cover-
150 to 250 eggs, and (theoretically at least)
ing strategy between the time of planting
as few as 10 moths can cause 100 percent
and flowering. infestation on a single acre of squash-fam-
ily plants. (8) Occasionally, small borers
Life Cycle and Characteristics: may also enter leaf stems. The burrowing
Squash Bug larvae destroy the internal vascular tissue
and cause the whole plant or the invaded
Related ATTRA Adult squash bugs pass the winter under
runner to wilt and die. Feeding may con-
Publications whatever shelter is available—including
tinue for four to six weeks. A sticky gob
leaves, boards, stones, and other debris. of excrement ( frass)—which resembles wet
Organic Pumpkin and
Winter Squash
The adult bugs re-emerge as soon as the sawdust—typically marks the entrance site.
Production weather warms, and mate soon thereafter. (9, 10) If a vine dies before the borer has
Squash bugs lay eggs in masses of a dozen completed its larval cycle, the larva can
Farmscaping to
or more on the underside of leaves, usually migrate to a neighboring plant and resume
Enhance Biological
Control in the vein axils. Eggs hatch in 10 to 14 feeding there. (8)
days. The nymphs pass through five instars
Season Extension over a period of four to six weeks to reach The squash vine borer larvae are whitish,
Techniques for wrinkled, brown-headed worms that can
Market Gardeners
maturity. Since the overwintering adults lay
eggs well into midsummer, all stages of the grow to about 1 inch in length. The adult
[hoophouses and row
pest’s lifecycle can be observed in the field moth, a member of the clear-winged moth
covers]
throughout most of the season. (6) Two gen- family, has translucent wings (wing expanse
NCAT’s Organic Crops
erations may occur in the South. of about 1.5 inches) with metallic green-
Workbook black and orange colors on the body and
Cucumber Beetles: Squash bug adults are easy to identify. wing fringes. The moth is a day flier, often
Organic and They are approximately 5/8-inch long, dark mistaken for a wasp.
Biorational IPM brown or mottled, and hard-shelled. Being
Generally, only one generation per year is
Overview of Cover true bugs, they have a long, shield-like produced in northern states, two genera-
Crops and Green shape and membranous-looking wing tips. tions in many southern states.
Manures They give off a disagreeable odor in large
numbers or when crushed. Nymphs are
delicate, with bright orangish-red heads, Planning for Control
legs, and antennae; the abdomen is green. Planning for control of squash bug in
As the nymphs age, they become grayish- organic production must begin before a
white with dark legs. (6) They range in size single seed or seedling is planted. Recent
from 1/10 to 2/5 of an inch. research has identified squash bug as a
vector for the newly named Cucurbit Yel-
Squash bug eggs are easy to identify. The low Vine Disease (CYVD). Once squash
orange-yellow eggs are each about 1/16-inch plants start to yellow from infection with
in length. Eggs appear in neatly ordered this virus, there is very little that can be
rows on the underside of host-plant leaves. done. The viral disease, which shows up
They gradually change to a bronze color as soon after transplanting, has been reported
hatch nears. (1) in Kentucky, Oklahoma, and Texas, and is
Page 2 ATTRA Squash Bug and Squash Vine Borer: Organic Controls

3. suspected in Ohio. The organism has been squash vine borer and the squash bug.
identified as Serratia marcescens. (11) However, producers should be aware that
the squash vine borer adults are strong fli-
Planning for squash vine borer control is
ers and have been known to find squash
likewise very important, since a very small
fields as far as one-half mile from their
population of borers can be highly destruc-
emergence site in another field. (8)
tive. Feeding within the plant stem, a sin-
gle borer can kill a whole plant or a large Field sanitation procedures are recom-
runner vine. mended as a measure of control of the
squash vine borer, as well. Vine residues
Levels of Control in Certified should be destroyed as soon as possible
after harvest to prevent late larvae from
Organic Production completing their lifecycle. (9, 10) Fall till-
The National Organic Program, adminis- age exposes cocoons (pupae) to predation
tered by the U.S. Department of Agricul- and deep incorporation in early spring fur-
ture (USDA), has set standards for pest ther helps to keep populations suppressed.
management. The Crop Pest, Weed, and (10) On the other hand, fall sanitation
Disease Management Practice Standard
A
procedures that leave the ground bare for
(Section 205.206) requires that produc- very small
extended periods are contrary to good
ers use a three-level hierarchical approach organic agriculture practice. Consider population
in deciding how to deal with pest planting cover crops or other measures that of squash
management problems. minimize the risks of erosion or compaction vine borers can be
Management levels 1, 2, and 3 in the fol- of bare soil. highly destructive.
lowing discussion describe three tiers of
pest management. See also the interpre- Mechanical and physical
tation of the National Organic Standards practices (level 2)
found in NCAT’s Organic Crops Workbook:
After cultural practices, mechanical and
A Guide to Sustainable and Allowed
physical practices provide a second line
Practices, p. 22.
of defense against pests. Such practices
include the use of barriers and nonsyn-
Systems-based practices (level 1) thetic lures, traps, and repellents such as
Cultural practices such as timing of plant- kaolin clay products. Level 2 practices also
ings, choice of cultivars, and field sanitation include developing habitat for beneficial
practices are examples of first-line, systemic predators and parasites.
strategies for pest management. Mulches
Iowa State University Organics Research
are known to harbor squash bugs. Help-
Program conducted trials of various con-
ful sanitation measures include removal of
trol methods for squash bug and squash
plant debris, soil incorporation of cucurbit
vine borer. Researchers found that mulch-
crop residue, and removal of old boards and
ing with newspaper and hay, combined
other overwintering sites. These practices
with tightly secured row covers on the plots
can prevent squash bug infestations.
(a level 2 control), provided very effective
Field sanitation techniques have both posi- control of both weeds and squash bugs in
tive and negative consequences in organic pumpkin (C. pepo)—especially in the wet
production. Some types of mulches used season of 2002. (4, 5) The row covers
for weed control appear to attract more apparently excluded squash bugs, prevent-
squash bugs than other types of mulches. ing them from entering to lay eggs.
(12) Removal of plant residues can be con-
Gauze row covers (e.g., Reemay™, Agri-
trary to good organic practice, unless a win-
force™, Agribon™, Tuf bell™) [Section
ter cover crop replaces the organic matter.
205.206(b)(1),(2),(3)] physically exclude
Annual rotation to non-curcubit crops is pests and prevent them from reaching
a primary step toward cultural control of the plants in large numbers. Preventive
www.attra.ncat.org ATTRA Page 3

4. strategies have become more important with Some products acceptable in organic veg-
recognition of A. tristis as a probable etable production that are effective against
disease vector. squash bugs include diatomaceous earth,
Hand picking and trapping of A. tristis, or sabodilla, and neem oil. Growers that
slitting each vine to remove the larva, in the anticipate using materials to control heavy
case of M. satyriniformis, represent attempts pest infestations must list these materi-
to control pests after they have begun rear- als and the circumstances for their use in
ing another generation in numbers sufficient their organic systems plan. This plan must
to cause economic damage and pest build- be submitted to and approved by the
up. Such labor-intensive controls may be organic certifier before the producer uses
uneconomical for large plantings. any material.
Botanicals and biorationals are discussed
Material (level 3) below in Alternative Insecticides.
Level 3 strategies include the wider use of Organic advisors strongly encourage early
biologicals and botanicals to control pests. cultural and other controls, rather than rely-
Organic producers also have the option ing on product applications after popula-
to use materials included on the National tions have been allowed to reach economic
List under Section 205.206(e)—“Synthetic threshold levels. www.ipm.ucdavis.edu/
substances allowed for use in organic PMG/r116301111.html According to Cor-
crop production.” nell University Extension, “application of
National Organic Standards Rule
Section 205.206 Crop pest, weed, and disease management practice standard.
a. The producer must use management practices to prevent crop pests, weeds, and diseases including but not limited
to:
1. Crop rotation and soil and crop nutrient management practices, as provided for in sections 205.203
and 205.205;
2. Sanitation measures to remove disease vectors, weed seeds, and habitat for pest organisms; and
3. Cultural practices that enhance crop health, including selection of plant species and varieties with regard to
suitability to site-specific conditions and resistance to prevalent pests, weeds, and diseases.
b. Pest problems may be controlled through mechanical or physical methods including but not limited to:
1. Augmentation or introduction of predators or parasites of the pest species;
2. Development of habitat for natural enemies of pests;
3. Nonsynthetic controls such as lures, traps, and repellents.
c. Weed problems may be controlled through:
1. Mulching with fully biodegradable materials;
2. Mowing;
3. Livestock grazing;
4. Hand weeding and mechanical cultivation;
5. Flame, heat, or electrical means; or
6. Plastic or other synthetic mulches: Provided, That, they are removed from the field at the end of the growing
or harvest season.
d. Disease problems may be controlled through:
1. Management practices which suppress the spread of disease organisms; or
2. Application of nonsynthetic biological, botanical, or
mineral inputs.
e. When the practices provided for in paragraphs (a) through (d) of this section are insufficient to prevent or control
crop pests, weeds, and diseases, a biological or botanical substance or a substance included on the National List
of synthetic substances allowed for use in organic crop production may be applied to prevent, suppress, or control
pests, weeds, or diseases: Provided, That the conditions for using the substance are documented in the organic
system plan.
Page 4 ATTRA Squash Bug and Squash Vine Borer: Organic Controls

5. approved products is not currently a viable the ground. Row covers are removed just
management option” for squash vine borer. before female blossoms appear, to facili-
www.nysaes.cornell.edu/pp/resourceguide tate pollination. For more information on
use of row covers,
Iowa State Organic Research (Gerber trials) see ATTRA’s Season
Extension Techniques
In 2002 Kathleen Delate, Organic Crops Specialist at Iowa State University, for Market Gardeners.
began comparative field trials on methods of insect control in organic pro-
duction of winter squash, four zucchinis (representing summer squash,
usually sold as fresh produce, rather than processed), and pumpkins. This Host
first trial included specific squash and pumpkin cultivars—many of them
bush, rather than vining types. It is unclear why the specific cultivars
Preference
listed in the Abbe Farm profiles (below) were selected for the initial trial; and Genetic
according to Ashworth, the named cultivars represent three distinct squash
species—C. moschata, C. maxima, and C. pepo. Production was destined
Resistance
for the organic baby food market. With two cooperating farmers, Delate It is important to use
established sites to evaluate how three methods of pest management scientific nomencla-
affected plant health and crop yields. Subsequent trials in 2002 and 2003 ture when discuss-
R
narrowed the cultivar range to C. moschata varieties for which squash bug ing cucurbit crops,
and squash vine borer show inverse preferences. ow cov-
in order to identify
In the first year, the three methods consisted of: species and subspe- ers must
cies correctly. The be tightly
• A kaolin clay product applied bi-weekly from plant emergence
until a month before harvest
terms squash and secured to be effec-
pumpkin are used in tive in excluding
• Interplanting of buckwheat to supply food for a fly parasite the produce industry
(tachnid fly) of the squash bug, and insects.
and among home gar-
• Reemay™ row cover, a gauze-like fabric used to prevent coloniza- deners to refer to a
tion by the pests. confusing variety of
After the second year, project results indicate a slight preference for row cucurbits. Scientifi-
covers as the most effective method to control both squash bug and squash cally, there are either
vine borer. Varieties of C. moschata were the only cultivars trialed after five or six recognized
the first year. (4) species: C. pepo, C.
moschata, C. mixta,
C. maxima (the four
types commonly found in U.S. markets)—
Row Covers plus C. ficifolia (known as chilacayote in
A two-year organic squash and pumpkin Mexico and commonly used in candies)
variety trial from West Virginia found ben- and C. foetidissima (the foul-smelling wild
efits for row covers comparable to the Iowa “Buffalo Gourd,” sometimes employed as
State work. (13) Row covers must be tightly a source of seeds pressed for oil). These
secured to be effective in excluding insects. species were established and defined by
Especially in areas with high winds, row the fact that members do not cross when
covers have to be securely anchored to planted near each other. However, evidence
Regionality
The results of the Iowa and West Virginia pest management trials are preliminary and regional. For instance, squash vine borer
is not a significant problem in the West (west of Interstate 35). In general, organic growers need to be guided primarily by
research done in their own regions. The University of California IPM Web site, however, presents very similar recommenda-
tions to what these research studies suggest: field sanitation and crop rotation to break pest cycles in the field, and use of row
covers to prevent infestation from nearby pest hatching sites. www.ipm.ucdavis.edu/PMG/r116301111.html Research remains
to be done—region by region and under weather conditions that may differ markedly from year to year—on the best organic
methods to control insect pests on all varieties and market types of Cucurbita.
www.attra.ncat.org ATTRA Page 5

6. suggests that C. mixta may cross with C.
moschata under certain conditions. (14) Cultivar Preference of Squash Vine
Borer
C. pepo includes all the “summer squash”— Scientific
i.e., preferred culinary use is before matu- Variety or Type Rating
name
rity—most “pumpkins,” and hard-shell Blue Hubbard C. maxima
keepers like acorn, as well as novelties such 5
(Hubbard type)
as spaghetti squash. However, “Cushaw Boston Marrow 4 C. maxima
pumpkins” are C. moschata, and some (Hubbard type)
“white pumpkins” are C. maxima. Some-
Golden Delicious 4 C. maxima
times giant orange varieties, such as C. (Hubbard type)
maxima, are marketed as pumpkins.
Connecticut Field 4 C. pepo
A 1990 study at Oklahoma State Univer- pumpkin (ornam.)
sity of ovipositional preference by squash Small Sugar 4 C. pepo
bugs found a decided preference for yel- pumpkin
low straightneck and crookneck (C. pepo), (ornamental)
as compared with zucchini, acorn, spaghetti Zucchini 4 C. pepo
T
he bottom (all C. pepo), and butternut (C. moschata). White Bush 3 C. pepo
(15) Other studies have found a squash Scallop
line is that
bug preference for C. maxima and C. mixta
any organic Acorn 3 C. pepo
over some types of C. pepo. Acorn squash
grower who wishes and all the C. moschatas are quite tolerant Summer 2 C. pepo
crookneck
to raise squashes of squash bug damage. (16, 17) Cocoz-
elle (C. pepo) has been identified as an Dickenson 2 C. moschata
and pumpkins must
extremely susceptible sub-type of zucchini. pumpkin
grow varieties pre-
A research study in Texas found C. foetidis- Green striped 1 C. mixta
ferred by the cus- sima extremely distasteful to squash bugs, cushaw
tomers, and cannot as well as to humans. (18) Butternut 1 C. moschata
rely on “host pref-
The University of Illinois rated the suscep- elsewhere and could account for some of the
erence and genetic tibility of twelve varieties (types) of squash Iowa State results as a “missing variable.”
resistance” to deter on degree of resistance to squash vine borer Feeding preferences have been studied pri-
squash bugs. attack. The list corresponds almost exactly marily in the context of cultural manage-
to the four sub-types of squashes cultivated ment of cucumber beetle through the use
in the U.S. A rating of 1 indicates most of trap crops. (20, 21) (See the ATTRA
resistant to vine publication Cucumber Beetles: Organic and
borer; a rating of 5, Biorational IPM.)
least resistant. (19)
When applied to squash bug and squash
A l so, see the vine borer control, research on feeding
ATTRA publication preferences does not address market prefer-
Organic Pumpkin ences. The bottom line is that any organic
and Winter Squash grower who wishes to raise squashes and
Production. pumpkins must grow varieties preferred
Investigation into by the customers, and cannot rely on “host
host preferences preference and genetic resistance” to deter
of squash bug and squash bugs. Squash bug control in pump-
squash vine borer kins cannot be achieved by simply sub-
and inferred genetic stituting ‘Cushaw’ for the jack-o-lantern,
resistance, while not nor can patty pan be considered a substi-
an objective of the tute for the ‘Prolific straightneck’ or the
Iowa State trials, highly desirable fresh market ‘Cocozelle.’
Pumpkin.
has been carried on (16) A winter squash producer having a
Page 6 ATTRA Squash Bug and Squash Vine Borer: Organic Controls

7. Farm Profile: Abbe Hills Farm, Mt. Vernon, Iowa
Abbe Hills Farm, managed by ISU farmer cooperator Laura Krause, was one of two farms
participating in a two-year trial of pest control methods in certified organic squash pro-
duction intended for Gerber Products, Inc. The project evaluated methods of pest man-
agement in terms of pest suppression and crop yields, in addition to the productivity
(plant performance and health) of organically raised squash. Other heirloom vegetables
were raised as part of the trial, as well, and processed at the Iowa State University Food Sci-
ence Department according to Gerber specifications for baby food.
Heirloom squashes raised in 2001 in the trial plots at Abbe Hills included the following. No
other cucurbits were grown.
Winter squash
Table Queen (C. pepo)
Early Butternut (C. moschata) hybrid
Burgess Buttercup (C. maxima)
Heart of Gold (C. pepo) hybrid
D
[sweet dumpling acorn type] elayed
Sweet Dumpling (C. pepo) planting
[sweet dumpling acorn type] has some-
Cream of the Crop (C. pepo) hybrid times been sug-
(semi-bush)
gested as a means to
Table Ace (C. pepo) hybrid
(semi-bush) control both squash
Summer squash bug and squash vine
borer.
Zucchinis (C. pepo)
Costata Romanesco, Nimba,
Aristocrat (hybrid), Cocozelle
(hybrid), Black
Pumpkins
Ghost Rider (C. pepo)
Howden (C. pepo)
Orange Smoothie (C. pepo) hybrid
Racer (C. pepo) hybrid
Findings reported after two years clearly showed row covers to be a superior method of
pest management, based on yields, plant health, and absence of squash bugs in all stages
of development.
problem with vine borers will undoubtedly find insect and disease management comments
it easier and more cost-effective to take on “possible organic controls that lack effi-
different measures to control the pest cacy.” (22) Some are discussed below.
than to convince the marketplace to accept
butternut as a substitute for 'Giant Blue Delayed planting has sometimes been
Hubbard.' suggested as a means to control both
squash bug and squash vine borer. Con-
ditions for success seem to limit its use
Other Cultural and Physical rather narrowly.
Controls
Research can be useful to show what is • A moderately long growing season
not effective, as well as what does work. A • No neighbors growing any of the
2005 Cornell University guide for organic cucurbits
www.attra.ncat.org ATTRA Page 7

8. • No wild cucurbits to serve as hosts Recommended strategies
A method in use to control squash vine Among the successful strategies to suppress
borer is syringe injection of the bacterial squash bugs on a larger scale are field sani-
insecticide Bt (Bacillus thuringiensis) into tation techniques. The use of postharvest
each vine by hand. In home gardens or tillage—routinely recommended to destroy
small market gardens, growers often try overwintering sites and to bury the adults—
to control squash bugs by hand picking has worked well to control both squash bug
or placing wooden boards near the plants, and squash vine borer.
where squash bugs will congregate for hand
collection and disposal. For squash vine Sanitation procedures that remove crop res-
borer, small growers are advised to slit idues by burning or high-temperature com-
each vine showing frass (the insect excre- posting are also successful. (1, 11, 15) It
ment) and extract the larva before the vine is helpful to clear adjacent areas of litter,
is irreparably damaged. Such methods leaf piles, and (especially) cucurbitaceous
are not suitable for commercial production weeds, as well. Burning crop residues is
of three or four acres because of the hand permitted as an exception to Organic Stand-
ard Section 205.203c(3) for the express
A
labor involved.
mong the purpose of disease suppression. High-tem-
successful perature composting would be preferable.
Experimental, creative These strategies, when approved by a cer-
strategies
to suppress squash
approaches tifying agent, should be viewed as stopgap
Eero Ruuttila, an organic farmer from New measures and not be employed as part of a
bugs on a larger long-term crop management plan.
Hampshire, has observed that squash bug
scale are field sani- oviposition on vines tends to take place dis- Fall tillage and cover cropping is the norm
tation techniques. proportionately on the growing ends of mid- in organic squash production. Research
season offshoots. He harvests one-third of from Oklahoma State found that plastic
the young vines in July and August, before mulch provided squash bugs with more
the eggs hatch, and sells the harvested off- shelter from sprayed insecticides than did
shoots in ethnic markets. (23) Harvesting other types of mulch. (20) Mulch used in
a marketable alternative crop for a specialty the Iowa State study (first year) consisted of
market is a creative way to avoid—rather newspaper and hay, which provided good
than solve—pest problems. weed control. (4)
An experimental technique for squash bug
control is companion planting with repellant National Organic Standards Rule
plants—catnip, tansy, (16) radishes, nastur-
Section 205.203 Soil fertility and crop nutrient
tiums, or marigolds, (6) beebalm, (24) or management practice standard.
mints. (25) For more information on such
strategies, ask for ATTRA’s Companion e. The producer must not use (3) burn-
ing as a means of disposal for crop
Planting publication.
residues produced on the operation:
Except, that burning may be used to
suppress the spread of disease or to
stimulate seed germination.
Marigold. Crop rotation is a recommended production
practice that reduces squash pests within a
field. Rotation can contribute to pest sup-
pression by delaying population build-up
early in the season. Rotation does not, how-
ever, provide complete, reliable control of
either pest because adults can move easily
Page 8 ATTRA Squash Bug and Squash Vine Borer: Organic Controls

9. between fields. Sustaining vigorous plant
growth is a very important part of a borer Table 1. Squash harvest parameters. Pratt Farm, 2001 (5)
control strategy. Supplemental fertilization Treatment Yield (lbs)/acre ± SE Fruit/acre ± SE
may be necessary to promote the vigorously
Control 2,472.9 ± 663.3 1,375.0 ± 291.7
growing plants that can tolerate one or two
borers and still produce a crop through Surround™ [kaolin clay] 3,580.8 ± 2246.1 1,708.3 ± 718.1
additional rooting along the stem. (10) Buckwheat intercrop 1,901.7 ± 986.9 1,000.0 ± 343.6
LSDO.05 nsd nsd
Biological Control
Biological control was part of the Iowa Table 2. Squash harvest parameters. Abbe Hills Farm,
State Study. Buckwheat was interplanted to 2001 (5)
attract the tachinid fly parasitoid, Trichop- Treatment Yield (lbs)/acre ± SE Fruit/acre ± SE
oda pennipes, of A. tristis. T. pennipes depos-
Control 13,812.5 ± 1,226.4 6,437.5 ± 437.5
its eggs on large nymph and adult squash
bugs. After hatching, tachinid fly larvae Surround™ 12,750.0 ± 4,165.8 5,625.0 ± 1,419.7
feed on the squash bug, eventually killing Buckwheat intercrop 2,000.0 ± 639.4 1,062.5 ± 213.5
it. Unfortunately, the victim may continue Row cover 13,937.5 ± 2,303.5 6,562.5 ± 868.3
to feed and lay eggs for a while after it has LSDO.05 7,637.2 2,671.4
been parasitized. Therefore, even parasit- (5)
ism levels as high as 80 percent may not
prevent measurable economic damage. (26)
Populations of squash bug can also be
The Iowa State study found that planting a
suppressed by the presence of other natu-
buckwheat intercrop to enhance tachinid fly
ral predators. Limiting pesticide use is a
parasitism consistently outperformed appli-
most important step in protecting these ben-
cations of kaolin clay in reducing squash eficials in agricultural systems. They can
bug infestations. However, squash yields in be further encouraged through the use of
the buckwheat intercrop plots were reduced beneficial habitats, or refugia, in the form
by a factor of at least six at Abbe Hills Farm of cover crops, strip plantings of diverse
and a factor of three at Pratt Farm, when crops, and maintenance of desirable non-
compared with the row-cover trial plots. crop border areas. For more information
on creating habitat for beneficials (refugia),
see the ATTRA publication Farmscaping to
Enhance Biological Control, www.attra.org/
attra-pubs/farmscape.html, also available in
print upon request. For squash bugs, gen-
eralist predators include spiders, predatory
mites, disease organisms, and a number of
beneficial insect species—especially ground
beetles and robber flies. At least one egg
parasitoid of squash vine borer has been
identified that helps to keep its numbers
under control (8, 9, 23). Parasitic nema-
todes can be effective predators. Cornell
Extension points out that soil treatments
Tachinid fly (Trichopoda pennipes). will not reliably control squash vine borer,
as adults are strong flyers.
The “Results and Discussion” section of the
report noted: “The number of squash per Because a single borer can be so highly
plot and yields were significantly less in the destructive, biological controls have not
squash plots intercropped with buckwheat.” been considered a key strategy in man-
(4) (See Table 2.) aging the squash vine borer. (9)
www.attra.ncat.org ATTRA Page 9

10. Kaolin Clay All pesticides pose known and potential risks.
Comparison of Kaolin Clay (Surround™) treatment with When applying any pesticide, be certain to fol-
other physical and mechanical pest control methods low label instructions and use appropriate protec-
in the second-year Iowa State study showed “no sig- tive gear. Some natural substances used in organic
nificant difference” in populations of squash bug and production as pesticides can have significant toxic
squash vine borer or in populations of beneficials effects. The decision to use any pesticide should be
among the three pest management treatments. It should made only when other approaches to pest manage-
be noted that this trial involved only C. moschata— ment fail to provide adequate protection, and after
next to C. foetidissima, the type least preferred by plans for application have been included in the
squash bugs. (4, 5) organic system plan that has been approved by the
organic certifier.
In 2003 and 2004, further trials were held at Iowa
State, comparing two different Kaolin Clay formula-
tions—Surround-WP and Surround-XP—on Waltham
References
Butternut Squash (C. moschata) at the Nerely-Kinyon 1. McKinlay, Roderick G. 1992. Vegetable Crop
Research Farm, Greenfield, Iowa. Nine rows were Pests. CRC Press, Boston, MA. p. 143.
treated with Surround-WP, applied on a bi-weekly basis 2. Sorensen, Kenneth A. 1994. The squash vine
from plant establishment until plant leaf senescence; borer. Cooperative Extension, North Carolina
nine rows, with Surround-XP, applied the same. A con- State University, Raleigh, NC.
trol plot received no treatment. There was no signifi- www.ces.ncsu.edu/depts/ent/notes/Vegetables/
cant difference found among the three plots in yields veg20.html
(measured by count and individual squash weights) or
presence of insects. (27) 3. Anon. No date. Squash vine borer. Lane Agri-
cultural Experiment Station, Oklahoma State Uni-
versity, Lane, OK. www.lane-ag.org/
Alternative Insecticides
Organic growers have traditionally used botanical insec- 4. Delate, Kathleen. 2002. Progress Report to Ger-
ticides such as sabadilla, ryania, rotenone, or various ber Products, Inc.: Organic Squash Pest Manage-
blends of these to control squash bug. However, most ment Trials and Heirloom Vegetables. January 9.
botanicals have generally proven to be a bit expensive Iowa State University, Ames, IA. 6 p.
and only marginally effective. For information on what http://extension.agron.iastate.edu/organicag/
to use, see “What can I use in organic production?” researchreports/gerber.pdf
on page 20 and Chapter VIII, Pest and Disease 5. Delate, Kathleen. 2003. Progress Report to
Management, pages 25–29, in NCAT’s Organic Gerber Products, Inc.: Organic Squash Trials.
Crops Workbook. Also consult the Organic Materi- February 12. Iowa State University, Ames, IA.
als Review Institute (OMRI) for more information on http://extension.agron.iastate.edu/
insecticides permitted in organic squash production organicag/
(www.omri.org).
6. Bessin, Ric. 2004. Squash Vine Borer and
In all cases where pesticides—natural or synthetic—are Squash Bug. www.uky.edu/Ag/Entomology/
used, timing is critical. Application should coincide entfacts/veg/ef314.htm
with maximum egg hatch, because the nymph stage is
most vulnerable. Timing can be judged by frequent 7. Friend, R.B. 1931. The Squash Vine Borer.
and careful field scouting. In organic farming, there Bulletin 328. Connecticut Agricultural Experi-
is no substitute for the eye of the farmer. Monitoring ment Station, University of Connecticut, New
squash bug emergence is not difficult, as the egg clus- Haven, CT. 25 p.
ters are easy to find and identify. Egg placement and
8. Worthley, Harlan N. 1923. The Control of the
hatch occur on the undersides of leaves, and the nymphs
Squash Vine Borer in Massachusetts, Bulletin No.
tend to remain there. Therefore, to be effective, pesti-
218. Massachusetts Agricultural Experiment Sta-
cide sprays or dusts must reach these areas and blan-
tion, Amherst, MA. 80 p.
ket them thoroughly. Since hatching occurs continually
throughout the season, subsequent treatments will be 9. Sorensen, Kenneth A., and James R. Baker.
required to assure sufficient control. (28) 1983. Insect and Related Pests of Vegetables:
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11. Some Important, Common, and Potential Pests in University of Illinois, Urbana, IL.
the Southeastern United States. Pub. AG-295. www.urbanext.uiuc.edu/bugreview/
North Carolina State University, Raleigh, NC. squashvineborer.html
173 p.
20. Palumbo, John C. 1988. Innovative methods of
10. Metcalf, Robert L. and Robert A. Metcalf. 1993. coping with squash bugs on cucurbits. Proceed-
Destructive and Useful Insects: Their Habits and ings of the 7th Annual Oklahoma Horticulture
Control. McGraw-Hill, Inc., New York, NY. p. Industries Show. p. 152–155.
14.38–14.39.
21. Naegely, Stella K. 1997. Faking out bugs.
11. Bruton, B.D., et al. 2003. Serratia marcescens, a American Vegetable Grower. August.
Phloem-Colonizing, Squash Bug-Transmitted Bac- p. 38–39.
terium: Causal Agent of Cucurbit Yellow Vine Dis-
22. Cornell University. 2005. Resource Guide for
ease. Plant Dis. 87:937-944.
Organic Insect and Disease Management.
www.apsnet.org/pd/abstracts/2003/
www.nysaes.cornell.edu/pp/resourceguide/cmp/
dau03ab.htm
cucurbit.php
12. Staff. 1990. Mulch attracts squash bugs.
23. Stoner, Kimberly A. (ed.) 1998. Proceed-
HortIdeas. November. p. 126.
ings: Alternatives to Insecticides Conference.
13. Van Tine, Melissa, and Sven Verlinden. 2003. Abstracts: Cucurbit crops. Connecticut
Managing Insects and Disease Damage under an Agricultural Experiment Station (CAES), New
Organic System. West Virginia Extension, Mor- Haven. 2 p. www.caes.state.ct.us/
gantown, WV. 3 p. AlternativestoInsecticides/Abstracts/
www.wvu.edu/%7Eagexten/farmman2/organic/ abstractcucurbit.htm
insects.pdf
24. Garrett, J.H. 1993. J. Howard Garrett’s Organic
14. Ashworth, Suzanne. 2002. Seed to Seed. Manual. The Summit Group. Fort Worth, TX.
Seed Saver Publications, Decorah, IA. p. 114, 121.
15. Bonjour, E.L., W.S. Fargo, and P.E. Rensner. 25. Patterson, Peg. 2000. Peppermint defeats those
1990. Ovipositional preference of squash bugs nasty squash bugs. Organic Gardening. Vol. 48,
(Heteroptera: Coreidae) among cucurbits in Okla- No. 2. p. 70–71.
homa. Journal of the Entomological Society of
26. Hoffman, Michael P., and Anne C. Frodsham.
America. Vol. 83, No. 3. p. 943–947.
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16. Ellis, Barbara W., and Fern Marshall Bradley. Cornell University Cooperative Extension. Ithaca,
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examination of Kaolin Particle Film for Insect
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Insect Pests of Farm, Garden and Orchard, 8th www.organicaginfo/upload/
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28. Bishop, Beth A. 2000. The Vegetable Growers
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p. 5–8.
Note: For an assessment of C. foetidissema poten-
tial in biodiesel production, see the ATTRA publica-
tion Biodiesel: The Sustainability Dimensions.
19. Grupp, Susan M. No date. The bug review:
Squash vine borer. Cooperative Extension,
www.attra.ncat.org ATTRA Page 11

12. Squash Bug and Squash Vine Borer: Organic Controls
By Katherine L. Adam
NCAT Agriculture Specialist
©2006 NCAT
Paul Driscoll, Editor
Cynthia Arnold, Production
This publication is available on the Web at:
www.attra.ncat.org/attra-pub/squash_pest.html
and
www.attra.ncat.org/attra-pub/PDF/squash_pest.pdf
IP298
Slot 117
Version 022808
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