Evaluations of OMRIListed Organic Insecticides for Vegetable Insect Control

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Evaluations of OMRI-Listed Organic Insecticides
for Vegetable Insect Control   Gale
n Dively Department of Entomology, University of
Maryland
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National Organic Program Code 205.206   Crop
pest, weed, and disease management practice
standard. (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, the conditions for using
the substance are documented in the organic
system plan. Should be considered a solution of
last resort.
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Insect/Disease Control Products Allowed for Use
in Certified Organic Production
Bacillus thuringiensis - 18 Beauveria bassiana -
3 Biofungicides 16 Copper Products 15 Mineral
Dusts 3 Ferric Phosphate 5 Garlic Products
13 Limonene 3 Neem Products 25
Nematicides 2 Oils 21 Pheromones 30
Plant Pesticides 30 Pyrethrum 9 Soaps
19 Spinosad 11 Sulfur Products 28 Virus
Sprays 4
Organic Materials Review Institute (OMRI) list
46 generic categories of products that are
certified organic under the USDA National Organic
Program.
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Insect/Disease Control Products Allowed for Use
in Certified Organic Production
Bacillus thuringiensis - 18 Beauveria bassiana -
3 BioFungicides 16 Copper Products 15 Mineral
Dusts 3 Ferric Phosphate 5 Garlic Products
13 Limonene 3 Neem Products 25
Nematicides 2 Oils 21 Pheromones 30
Plant Pesticides 30 Pyrethrum 9 Soaps
19 Spinosad 11 Sulfur Products 28 Virus
Sprays 4
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• Problems and Limitations with Organic
  Insecticides
• Relatively short-lived
• Require frequent applications
• Require complete coverage and precise timing

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• Problems and Limitations with Organic
  Insecticides
• Relatively short-lived
• Require frequent applications
• Require complete coverage and precise timing
• No systemic activity
• Short shelf life
• Not available in small units

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• Problems and Limitations with Organic
  Insecticides
• Relatively short-lived
• Require frequent applications
• Require complete coverage and precise timing
• No systemic activity
• Short shelf life
• Not available in small units
• May lack registration status
• Most products are restricted
• Expensive
• Lack efficacy information

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Timing Plots treated 1-6 times every 7 days,
depending on test. Diluted spray volume 35-40
gal/acre at 40 psi. Spray equipment options CO2
backpack sprayers small tractor-driven boom
sprayer high-clearance drop nozzle sprayer
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• Pesticidal Soaps (M-pede, Safer Soap)
• Potassium or ammonium salts of fatty acids.
• Work by smothering soft bodied pests and
• disrupting their cuticle layer.
• Requires complete spray coverage to thoroughly
  coat the pest.
• Hardness of water must be neutralized.
• Generally provides short-term partial control of
  some aphids, mealybug, whitefly, mite, and other
  soft-bodied species.
• Phytotoxicity is a concern with soap products.

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• Oils (Vegetable, Petroleum, Neem)
• Widely used to smother the egg and immature
  stages of various mites and insects. Some
  products repel pests.
• Generally provide longer control than soaps.
• Control soft-bodied insects such as aphids,
  mites, thrips, whiteflies, mealybugs, and
  psyllids.
• Neem Oil (Trilogy) and Clove Oil (GC-Mite) have
  shown effectiveness against spiders and cyclamen
  mites.
• Use of oils in warm temperatures may cause
  phytotoxicity in some crops.

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• Garlic Products and Plant Pesticides (Extracts)
• Rosemary Oil (Ecotrol)
• Disrupts neuroreceptors in insects and mites.
• Fair to good control of spider mites but poor
  control of cyclamen and rust mites.
• Fair to good control on potato aphids on
  tomatoes with adjuvants equivalent to PyGanic
  and Neem products.
• Garlic extract (Garlic Barrier) and Cedar Oil
  (Cedar gard)
• Act as repellants.
• Some studies report reduction in damage by
  cabbageworms, fruitworms, certain armyworms, and
  tomato pinworm.
• No experimental evidence of effective control
  for sucking insects (plant and stink bugs).

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• Mineral Dusts (Surround WP, 95 kaolin.
• Diatect V 82.5, diatomaceous earth
• 0.5 pyrethrins
• Repellency action - white film visually
• repels some insects, or acts to disguise the
  plant.
• Irritation action - particles stick to insect
  body causing excessive grooming.
• Film layer acts disrupts feeding and egg-laying.
• Used to control leafhoppers on grapes and other
  fruit crops.
• Diatect V better than Surround because it
  contains pyrethrins.
• Some evidence of fair to good control of stink
  bugs in tomatoes treated with Surround
  (75lb/acre).
• Residues may not acceptable for fresh market.
• Surround has also been shown to suppress certain
  diseases.

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• Spinosad (sprays, baits, granulars)
• Entrust, Conserve, GF-120 NF Naturalyte
• Dry wettable powder sold in one pound packages.
  
• Contained 80 spinosad, composed of substances
  produced by aerobic fermentation of the
  actinomycete Saccharopolysora spinosa.
• Fast-acting, somewhat broad-spectrum acts
  through ingestion or by direct contact to
  activate the nervous system of the insect,
  causing loss of muscle control.
• Very effective on caterpillars, fly larvae, and
  thrips very good control of Colorado potato
  beetle larval stages fair to good control of
  flea beetles and Mexican bean beetles.
• Provides poor control of sucking insects, such
  as aphids, whiteflies, leafhoppers, and true
  bugs.

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Means within a column followed by the same letter
are not significantly different (P 0.05).
Means within a column followed by the same letter
are not significantly different (P 0.05).
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• Pyrethrum PyGanic 5 and 1.4 EC (MGK Co.)
• Derived from pyrethrum daisy flowers
• similar MOA to the synthetic pyrethroids.
• Used widely and readily available.
• Good control of leafhoppers for 4-5 days
• at higher rates (16-32 oz per acre).
• Fair control of aphids, whiteflies, thrips, and
  flea
• beetles. May flare thrips.
• Some knockdown activity against cucumber beetles
  and Colorado
• potato beetles, but requires tight spray
  schedules.
• Disperses Japanese beetles for 2-3 days.
• Poor to fair control of caterpillars.

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• Neem Extracts and Derivatives
• Sold as oils, soaps, and extracts containing
  azadirachtin.
• 25 products derived from the neem tree.
• Multiple MOAs interfers with insects ability
  to molt. Also repels and deters feeding.
• Act primarily on immature stages.
• Fair to good control of Mexican bean beetles,
  Colorado potato beetles, and some caterpillars.
• Some suppression of flea beetles and cucumber
  beetles.
• Generally fair to good control of aphids.
• Not much activity on stink bugs and thrips.
• Works much better at lower rates
• mixed with pyrethrum

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Mexican Bean Beetle on Green Beans
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• Combination of Neem (azadirachtin) and Pyrethrum
• Provides additional residual and repellency
  action against leafhoppers and cucumber beetles.
• Best treatment tested for Japanese beetles.
• Significantly better cabbageworm and aphid
  control.
• Good squash bug control if applied as soon as
  eggs begin hatching.
• Fair control of squash vine borer if timed
  properly.

New Organic Product Coming Soon AZERA -
pyrethrum (1.4, same active ingredient in
Pyganic) and azadirachtin (1.2)
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• Bt products
• Derived from a spore forming bacteria found in
  the soil.
• Many subspecies and strains producing over 60
  different insecticidal proteins.
• Each protein has a specific spectrum of
  activity.
• Over 100 products registered in the US only 18
  allowed for certified organic production.
• Require ingestion by a susceptible insect to be
  effective.
• Generally effective against most lepidopteran
  species affecting cole crops, tomatoes, and
  peppers.
• Bt tenebrionis based sprays have been very
  effective against Colorado potato beetle but
  currently there are no approved formulations.

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Zea-later for dispensing vegetable and Bt
insecticide
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Hard-to-control insects
Cucumber beetles
Squash bug
Squash vine borer
Stink bugs Plant bugs
Plum curculio
Codling moth
Seed and root maggots
Aphids, Whiteflies
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• Improving Efficacy of Organic Insecticides
• Complete coverage is essential. 50-100 gal/acre
  may be needed for adequate coverage.
• Air-assist, electrostatic and drop nozzle can
  sprayers increase coverage. And arrange nozzles
  to cover all plant surfaces.
• Buffer water if advised by manufacturer.
• Calibrate your sprayer overdosing is expensive
  and can result in phytotoxicity.
• Apply when pests are in early stages of
  development.
• Addition of adjuvants to sprays can increase
  coverage and efficacy.
• Oil adjuvants tend to extend control.
• Soap adjuvants tend to result in better
  knockdown.

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• Compliance Points to Remember when Using Organic
  Insecticides
• National Organic Standards state that cultural,
  biological, and physical practices must be used
  before resorting to a pesticide.
• Document conditions for use.
• Make sure the product is registered.
• Keep records of the specific formulation used.

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Questions? Email with ideas for testing
products and for reports of field
trials. galen_at_umd.edu