Organic Pest Management Getting Started

Kimberly Stoner CT Agricultural Experiment Station

New Haven, CT

What is a pest?

• Pest is a category in our minds, not in nature.

• We may consider creatures pests because they:

1. Harm some resource we want to protect 2. Cause direct harm to humans (e.g. transmit

disease) 3. Annoy us with their presence

Know Your Potential Pests For each crop or other resource you need to protect: • What are the important pests? Consider weeds,

wildlife, diseases, and insects. • Which are priority items – those that can wipe out

a crop? • How often are they present? How often are they

damaging? • How can they be prevented? Monitored?

Managed?

Sources of information • Records for your farm – and maps for weeds • Other farmers in your area • People: CT Ag. Station, UConn Extension • New England Vegetable (or other crop) Guide • Weekly pest messages for your crops:

(UConn, UMass, MOFGA) • Organic Crop Production Guides from Cornell • Meetings: NOFA, New England Vegetable

and Berry Conference

Planning • Plan for prevention of pest and disease • Plan for how to monitor for problems • Plan for what you will do when problems arise

– e.g. when late blight or potato leafhoppers arrive

• If your farm will be certified organic, you need have all this in your Organic Systems Plan, and then you will need to keep records of implementation of the plan

Preventing Plant Disease: • Crop rotation • Resistant varieties • Disease-free seed and seed treatment (hot water or

biological treatment – not fungicides!) • Sanitation practices • Soil organic matter and health • Good water and air drainage • Remove alternate hosts and diseased plant residue • Avoid soil splashing • Growing some crops under cover

From last year’s weekly vegetable pest messages – Plant Diseases

• Cercospora leaf spot on spinach, chard • Downy mildew on crucifers • Downy mildew on basil • Downy mildew on cucumbers • Powdery mildew on cucurbits • Early blight and Septoria on tomatoes • Late blight on tomatoes • Phytophthora on pumpkins • Northern corn leaf blight on sweet corn

Preventing Insect Damage

• Good management of crop and soil • Crop diversification and resistant varieties • Insect barriers (row covers, tunnels) • Timing of planting and harvest • Encourage biological control – floral

resources for beneficial insects and pollinators

Economic Injury Level and Economic Threshold

Ed Zabroski, University of Illinois, via eOrganic

- New England Vegetable Recommendations – 2012 - 2013

Life Stage Low High

Adults 15 or fewer 25 or more

Small larvae 75 or fewer 200 or more

Large larvae 30 or fewer 75 or more

Examples of Economic Thresholds –

Number of Colorado Potato Beetle per 50 Potato Stalks (mid season)

vs. Potato Leafhoppers – Treat if more 1 adult per sweep or more than 15 nymphs per 50 leaves

Monitoring Techniques for Insects eOrganic – Geoff Zehnder

From last year’s weekly vegetable pest messages – Insects and Nematodes

• Flea beetles on Brassicas • Caterpillars on Brassicas • European corn borer (unusually low last year) • Striped cucumber beetles on cucurbits • Thrips on onions, garlic, leeks • Potato leafhoppers on bean, potato, eggplant • Corn earworm and fall armyworm in corn • Garlic bloat nematode in seed garlic

Spun-bonded Row Covers To exclude flea beetles and other insect pests, including: imported cabbageworms, squash bugs, cucumber beetles On 200 ft. beds of salad greens New Leaf Farm, Durham, ME

Barriers

Row covers are used on: • Cucurbits: to keep out striped cucumber beetle,

squash bug, squash vine borer. Must remove before flowering to allow pollination.

• Brassica greens and radishes: to keep out flea beetles, cabbage maggot, caterpillars

• Eggplants: to keep out flea beetles • Tomatoes (low tunnels): mostly to extend

season. Also provide protection from rain splash, may reduce disease

Timing to avoid insect pests: Examples

• Don’t plant cabbage family plants to the field before May 15 – avoid 1st generation cabbage maggot

• Plant cabbage family late in summer for fall harvest to avoid flea beetles (use row cover early in season)

• Cut all asparagus during the harvest season to eliminate sites for egg-laying by asparagus beetle

• Turn in bush beans immediately after harvest to avoid multiplying Mexican bean beetle

Biological Control: Using natural enemies to reduce damage from a pest population

• Predators • Parasitoids • Nematodes

• Insect pathogens • For plant pathogens – competitors, antagonists

• For weeds - herbivores

Predators

Parasitoids

Insect Parasitic Nematodes

Four basic approaches: 1. Importation: Bringing in a new natural enemy, not

present locally, from another part of the world 2. Inoculation: Re-introducing a natural enemy in a

local environment (for example, where it does not overwinter)

3. Inundation: Overwhelming the pest with natural enemies to bring down the population in the short term

4. Conservation: Providing resources or habitats for natural enemies already present to make them more abundant or effective

What’s Worth the Money? Questions to consider: • What does it cost? • How much damage does the pest do? And what is

the value of the crop that would be lost? • How effective is the natural enemy or organic

pesticide? • What are the other alternatives? • What are the specifics I need to know in order to

make it work?

Conservation: Basic principles • Reduce broad spectrum pesticide use as much as

possible (even pyrethrin, spinosad, and neem can cause problems)

• Learn to recognize the natural enemies of your pests (and other beneficial insects)

• Provide flowers with nectar and pollen throughout the season

• Provide shelter – over the winter, during inactive times of day. Minimize soil disturbance

• Be aware of alternate prey or hosts that may support natural enemies

Pollen and nectar sources

Pollinators in Crisis • Continuing loss of honey bees from mites –

Beekeepers normally lose 20% of their hives each year across the U.S.

• Loss of other bees, often poorly understood. Whole species of bumble bees have disappeared in the last 15 years in the U.S. and Europe.

Trichogramma

Trichogramma ostriniae against European corn borer

• Begin releases as soon as ECB start laying eggs (4-6 leaf stage of corn)

• At least 2 releases, 7-10 days apart • Rate: 30,000 to 60,000 wasps per acre

(depends on level of infestation and control) • Range of cost: $15 to $30 per release per

acre. Maximum cost (4 releases at 60,000 per acre): $120

How Do I Know If a Pesticide is Allowed?

• Preliminary check - Organic Materials Review Institute (OMRI). OMRI reviews materials used in organic agriculture for compliance with the National Organic Standards.

• Final authority – your certifier. Always notify certifier before using new inputs, even if it appears to be allowed. (Also for growers who plan to be certified in future)

A Good Source of Information on Efficacy of Organic Pest Management

Materials • Resource Guide for Organic Insect

and Disease Management • Focus is on vegetable and fruit

pests, but this is the best compilation of research results on many organic materials

• New edition coming out soon • Can download old edition -whole

book is online. •http://www.nysaes.cornell.edu/pp/resourceguide/

Organic Materials for Plant Disease Management

• Not my area of expertise – see references for efficacy data

• Biological materials: – Soil, seed, and in-furrow inoculants – Foliar sprays

• Oils – petroleum, neem, other plant oils • Mineral – copper compounds, sulfur, lime-sulfur • Kaolin, Potassium bicarbonate • Hydrogen dioxide disinfectants

Organic Materials for Insect Management

• Insecticides based on microbial materials • Soaps and Oils • Botanicals • Kaolin clay and other mined materials

Bacillus thuringiensis (Bt)

• Microbial product • Active ingredient is endotoxin produced by

bacteria • Must be ingested by pest • Several subspecies

– Bt kurstaki: caterpillars – Bt aizawai: caterpillars – Bt israelensis: larvae of flies (including mosquitoes,

fungus gnats) – Bt tenebrionis (San Diego): Colorado potato beetles- no

longer available

Many common caterpillars, including imported cabbageworm and tomato hornworm caterpillars, are easily controlled with Bt

Some OMRI Listed Bt Products Used against caterpillars: • Many products! Some brand names: • B.t. kurstaki: Biobit®, Deliver®,Dipel®,

Javelin®, Thuricide® • B.t. aizawai: Able®, Agree®, Xentari® Used against fungus gnats, B.t. israelensis: • Gnatrol ® WDG Used against mosquitoes, B.t. israelensis : • VectoBac® WDG, Mosquito Dunks

Chromobacterium subtsugae

• Newly discovered bacterium producing several compounds with complex modes of action

• OMRI listed products: Grandevo® • Labeled for use against many caterpillars,

aphids, psyllids, whiteflies, leafhoppers, plant-sucking mites, thrips, some true bugs (chinch bug, azalea lace bug, Lygus) and some beetles

• Many crops and sites

Spinosad Microbial product (from natural soil microbes) • Fast acting • Broad spectrum. One concern is toxicity to

bees • Affects insect nervous system • Concerns about evolution of insect resistance

Spinosad Effective against • Caterpillars • Colorado potato beetle • Thrips • Flies • Leafminers

Not effective against • True bugs • Aphids • Other sucking insects • Mites

Spinosad Products – OMRI List Examples: • Entrust® is labeled for a wide range of

vegetables, fruit, and tree farms • Conserve SC®, - labeled for ornamentals and

turf • Monterey Garden Insect Spray®

• GF 120 ® NF Naturalyte Fruit Fly Bait • Seduce ® Insect Bait – attracts earwigs and

cutworms

Efficacy of Insecticidal Soaps

• Generally effective against aphids, mealybugs, psyllids, mites

• Some good efficacy against caterpillars • Some efficacy against powdery mildews • Soaps are also mixed with other materials to

help them spread on the leaf surface

Examples of OMRI –Listed Soap Products

• Bayer Advanced Natria® Insecticidal Soap • DES-X Insecticidal Soap Concentrate • Garden Safe Insecticidal Soap® • M-pede® Insecticide Fungicide Miticide • Neudorff’s Insecticidal Soap Concentrate • Safer’s® Insectidal Soap Concentrate

Oils Many different kinds of oils available: • Plant oils (includes Neem oil – to be listed later)

– Golden Pest Spray Oil®, Natur’l Oil (soybean) – Garlic Barrier AG, BioRepel (garlic)

• Petroleum oils – Organic JMS Stylet Oil ® – Pht 440 Supreme Spray Oil – Monterey SAF-T-SIDE® Spray Oil – OMNI Oil 6E – Summit Year-Round® Spray Oil

• Mixtures (including mixtures of essential oils of herbs)

Efficacy of Oils

• Good to fair against small, soft-bodied insects: aphid, scales, mites, psyllids, some caterpillars

• Stylet oil traditionally used to interfere with the ability of aphids to transmit plant viruses

• Many oils have efficacy against powdery mildews and other plant foliar diseases

Neem • Derived from seeds and

oil of the neem tree • Broad spectrum

pesticide • Insect growth regulator • Deters feeding, egg

laying • Active against fungi and

bacteria • Some systemic uptake

by roots

Efficacy of Neem Products Azadirachtin-based products generally show

good or fair efficacy against: aphids, leafhoppers, leafmining flies, fungus

gnats, mealybugs, and mites with mixed results against: caterpillars, true bugs, and whiteflies • Neem-oil based products: efficacy against

aphids, spider mites, psyllids • Neem-oil also has efficacy against some

powdery mildews

Neem Products

• Many Products. Some examples - • Azadirachtin based: AZA-Direct®, Fortune Aza

Azadiractin 3%, Neemix 4.5® • Neem oil based: Monterey Neem Oil 70%,Neem

Oil RTU, Triact 70®, Trilogy® • Some products also combine azadiractin and neem

oil

Pyrethrum • Derived from powdered, dried flower heads

of Chrysanthemum cinerariaefolium, C. coccineum and C. marshalli.

• Broad spectrum • Toxic to bees • Rapid breakdown in soil and due to sunlight,

moisture • Rapid knockdown, but insects may recover • Note that pyrethroids are different!

Synthetic, more persistent, and some are carcinogenic or estrogenic.

Pyrethrum - Products Some OMRI Listed Products Concern ® Multipurpose Insect Killer Concentrate,

Evergreen® Pyrethrum Concentrate, Pyganic® EC 5.0 or ED 1.4

Piperonyl butoxide (PBO) is often added to pyrethrum products, and is prohibited for organic use. If PBO is present, it will be listed on the label, and it will not be OMRI listed

SurroundTM (kaolin clay) • Looks like a whitewash sprayed on the plants • Interferes with insect host finding and feeding – a

barrier. Also barrier to some fungi • Mostly tested for fruit pests – works well against

plum curculio, leafhoppers, etc. when well-timed • Also effective early in the season against

cucumber beetles, flea beetles on eggplant

Surround on apples – “whitewash” is non-toxic. Washes off apples, but difficult to wash off many products (berries, leafy greens)