Insect Management for the Organic Producer

Eric J. Rebek Associate Professor and State Extension Specialist Department of Entomology & Plant Pathology Oklahoma State University [email protected]

@EricRebek

Organic Options for Pest Management  Integrated Pest Management (IPM) Strategies 1.

2.

Cultural control Biological control 3.

4.

5.

Physical/Mechanical control Regulatory (legal) control Chemical control (OMRI approved)

1. Cultural Control

 Prevention: avoiding pest problems by modifying growing practices – Crop rotation to break pest cycle – Insect (and disease) resistance/tolerance – Polyculture – Trap crops – Sanitation

Crop Rotation

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Crop Rotation

 Corn rootworm (

Diabrotica

spp.) – eggs in soil – – Avoid corn following corn Note: Populations of Western corn rootworm and northern corn rootworms have adapted to corn-soybean rotations  Wireworms – larvae in soil – Avoid highly susceptible crops (e.g., root crops, corn, melons) following grassy sod or small grains – Note: some species remain as larvae for 3-6 years

Crop Rotation

 White grubs (

Phyllophaga

spp.) – larvae in soil – Avoid corn, potatoes, strawberries following grassy sod – Note: some species remain as larvae for 2-3 years  Colorado potato beetle (

Leptinotarsa decemlineata

) – adults in soil – Avoid repeated plantings of tomatoes, potatoes, or eggplant – Note: great distances and barriers to movement may be needed for adequate control

Insect Resistance/Tolerance

 Insect-resistant crop varieties – Bt corn • Transgenic resistance to caterpillars (e.g., corn earworm) – Glandular-haired alfalfa • “Hairy” stems of certain alfalfa varieties inhibit potato leafhopper

Polyculture

 Intercropping, cover crops, etc.

 Crop diversification can: – Reduce attractiveness of crops to pests that specialize on certain crops • Plant Apparency Hypothesis – Increase abundance and diversity of natural enemies that feed on pests • Natural Enemies Hypothesis

Trap Crops

 Non-crop plants more attractive to pests than cash crop  Interplanted within crop or around perimeter of crop

Trap Crops

 Sorghum and sunflower – leaf-footed bugs in southern tomatoes  Mustard – harlequin bugs in collards and other cole crops

Trap Crops

 Wide variety of species – stink bugs in many cash crops  Hubbard squashes – cucumber beetle in cash crop squashes

Sanitation

 Crop debris serves as harborage for pest insects  Remove and destroy debris  Burial, soil incorporation

2. Biological Control

The 3 P’s:

Predators, Parasites, Pathogens

P R E D A T O R S

Predators

Predators: larger than their prey, eat many prey, fast moving, generalist eaters

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P A R A S I T O I D S

Parasites (Parasitoids)

Parasitoids: smaller than prey, kill only one host, larvae are sedentary, many are specialists Parasitic wasps Parasitic flies

P A T H O G E N S

Pathogens (Microbial Control)

 Fungi – e.g.,

Beauveria bassiana

,

Metarhizium

spp.

 Bacteria – e.g.,

Bacillus thuringiensis

 Nematodes – e.g.,

Steinernema

spp.,

Heterorhabditis

spp.

 Protozoa – e.g,.

Nosema locustae

Gibellula sp.

Erynia sp.

Spider Leafhopper

Beauveria sp.

Hymenostilbe sp.

Cockroach

Beauveria sp.

Leafhopper Katydid Beetle

Biological Control (3 kinds)

 Classical (Importation) – Reunite old enemies; introduce natural enemies from pest’s geographic origin  Augmentation – Add what you need; supplemental release  Conservation – Conserve naturally occurring natural enemies

Conservation Biological Control

 Two main strategies: – Modify pesticide use to reduce exposure to natural enemies – Modify habitat in favor of natural enemy survival, longevity, and reproduction  Attract and retain naturally occurring predators and parasitoids in the crop – E-1023: Conserving beneficial arthropods in residential landscapes

How to Conserve the Good Bugs

 Reduce amount/frequency of pesticide use  Apply when beneficials are not active  Use selective products (e.g., Bt for caterpillar pests)  Apply “sweet water” to attract natural enemies  Use plants that help feed or shelter beneficials

Beneficial Flowering Plants

Tansy Coneflower Sunflower Caraway Dill Fennel Yarrow Wild Parsnip Fava Bean Goldenrod Coreopsis Cosmos Mustards Milkweed Buckwheat Sweet Clover Alfalfa Hairy Vetch

3. Physical/Mechanical Control

 Three main methods: – Barriers (exclusion) – Behavior modification – Destruction or killing

Exclusion

 Floating row covers and screens – cabbage maggot, flea beetles, cabbageworms  Adhesives and burlap – caterpillar pests and aphid-tending ants  Trenches – Colorado potato beetle (only those crawling, not flying)

Behavior Modification

 Two general methods: – “Push-Pull” technology – Mating disruption

Push-Pull Technology

 Repel (push) or attract (pull) insect pest away from crop  Use pheromones or other lures as baits  Trap crops can be considered a push-pull strategy  Visual attractants

Mating Disruption

 Grape Berry Moth (Mid May): – Place 250 to 400 Isomate-GBM ropes/A (use 400/A in high-risk vineyards) – – Prevents mating for 90 days in warm southern states Not generally recommended in OK because of small size of vineyards (< 5 acres)

Killing

 Crushing  Traps  Temperature  Suction

Killing

 Crushing – squash bug eggs on foliage  Traps – boards placed between rows for squash bug nymphs and adults

Killing

 Propane torches (flaming), hot-water immersion, steaming, solar heating – wide variety of insect pests  Suction – Colorado potato beetle, lygus bug – Care must be taken to not harm natural enemies

Additional Resources

 Association of Natural Biocontrol Producers – www.anbp.org (Info on Biological Control)  National Sustainable Agricultural Information Service (ATTRA) – https://attra.ncat.org  Sustainable Agriculture Research & Education (SARE) – www.sare.org

 IPM Oklahoma!

– entoplp.okstate.edu/ipm (Info on IPM)