Insect Control in the Organic Vegetable Garden Outline • Planning to avoid pests • Insect Monitoring and Identification • Fundamentals of Organic Insect.
Download ReportTranscript Insect Control in the Organic Vegetable Garden Outline • Planning to avoid pests • Insect Monitoring and Identification • Fundamentals of Organic Insect.
Insect Control in the Organic Vegetable Garden Outline • Planning to avoid pests • Insect Monitoring and Identification • Fundamentals of Organic Insect Control – Cultural Practices – Sanitation, exclusion – Attracting natural enemies – Botanical and biological pesticides • Key vegetable insect pests and control strategies Organic Control ‘Toolbox’ Example for Cucumber Beetle • • • • • • • • • • • Source: Univ. of Kentucky Entomology Habitat for natural enemies Grow cucurbit varieties less attractive to beetles Long distance crop rotation Transplant vs direct seeding Eliminate crop residues Manipulate planting date (may miss peak markets) Row covers (may interfere with weeding) Mulch (may exacerbate other pests) Trellis plants (labor) Trap crops, baits and sticky traps (labor, cost) Approved materials – Neem, Beauveria bassiana, kaolin clay, pyrethrin, spinosad First Steps Manage Soil for Healthy Plants • Soil test (pH, P, K, micronutrients) • Organic matter (cover crops, compost) • Fertility plan – Application based on crop needs • Avoid excess N • If planting in turf – Till before planting – Check for grubs Choose Less Susceptible Varieties • Hairy-leaf varieties • Tight husked corn – Corn earworm • Virus-resistance – GMO – Tomatoes – Cucurbits • Squash vine borer – ATTRA publication Avoid Pest Insects in Time Gather info on key pests • Early planted crops generally have lower insect pressure – Pests with multiple generations – Stink bugs, whiteflies, tomato fruitworm – Don’t prolong harvest • Late planting – Pests that overwinter locally – Cucumber beetles, bean leaf beetles Harvest before early July to avoid Pickleworm Avoid Insect Pests in Space Garden Layout Plan (learn crop families) • Rotate beds/plots to different plant families • Avoid successive plantings of same crop in adjacent beds • Maximize diversity – Interplanting – Mix different families – Add flowering plants Keeping Records Sampling Scheme • Begin sampling at planting • Sample weekly by crop • Sample enough plants to represent planting area, and that can be done in a reasonable time • Records will document what’s present, and whether populations are increasing, or decreasing Sampling Equipment To Spray or Not to Spray • Keep organic insecticides handy – Purchased, home-made • Decision to spray based on – Experience – Insect’s potential for damage • Type of damage (direct or indirect) – Stage of plant growth – Population trends (sampling records) – Does insect have natural enemies; are they present? Evidence of Natural Enemies Plants Can Tolerate Some Defoliation Example: Potatoes Plant Growth Stage Maximum Defoliation Without Yield Loss Plant emergence to early bloom 20% Early bloom 30% Late bloom till harvest 60% Insect Identification ID insects at least to Order, and if possible to Family Classification Kingdom -- Animal Phylum -- Arthropoda Class -- Hexapoda (= insects) Order -- Lepidoptera (= butterflies and moths) Family -- Noctuidae (= noctuids) Genus -- Helicoverpa Species -- Helicoverpa armigera (Tomato fruitworm, corn earworm Key Insect Orders Orthoptera: Grasshoppers and Crickets Hemiptera: True Bugs Thysanoptera: Thrips Key Insect Orders Coleoptera: Beetles Diptera: Flies Key Insect Orders Homptera: Aphids, whiteflies Lepidoptera: Butterflies, moths Hymenoptera: Ants, bees, wasps Arachnids: Mites and Spiders Spider mites Spiders Insect Metamorphosis Incomplete (12%) •Grasshoppers •True bugs •Aphids, thrips Complete (88%) •Beetles •Flies •Ants, wasps, bees Tips to Identify Larvae Lepidpotera (Caterpillars) Coleoptera: Beetles Tips to Identify Larvae Hymenoptera: Wasps Diptera: Flies Quiz: What are these? Hint: One on top will undergo complete metamorphosis; One on bottom; incomplete metamorphosis Cultural Practices Tillage • Disrupts insect pest life cycles • Exposes them to weather, predators • Destroys crop debris • Accelerates organic matter decomposition • Depletes food for microbes • Degrades soil structure, erosion Mulches Organic • Straw mulch – Retains soil moisture, lowers soil temperature – Habitat for predators (and some pests) – Excellent for potatoes, cucurbits Mulches Plastic • Black – Speeds early season crop growth • Reflective: – Repels thrips, aphids – Reduces spread of viruses Melon-Virus Experiments Cover crop as camouflage • Annual rye planted between rows in late fall • Virus incidence lower in cover crop treatments • Reflective mulch also reduced virus incidence 100 Cover No Cover 50 0 2003 2004 % Plants Infected with WMV Sanitation • Start with pest free transplants • Remove crop residue after harvest • Remove diseased plants • Remove weeds – Establish perennial and flowering plants for natural enemy habitat Exclusion High Pressure Spray (Aphids, mites, whiteflies) Water Wand: Cecil Stokes; E-mail ([email protected]) Attracting Natural Enemies Making use of Nature’s Services • Use of hedgerows in farming – Small trees, shrubs – Perennial grasses, forbs – Flowering annuals • Begin growing before crop • Provide food and shelter for natural enemies Attracting Natural Enemies Insectary Plants in the Garden • Establish insectary border(s) – Pick plants for successive bloom spring-fall – Fruit trees, flowering shrubs, perennial and annual flowers – Include low growing plants (ground beetles) Insectary Plants • Apiaceae (small parasitic wasps) – Fennel, coriander, dill, wild carrot • Compositacae/Asteraceae, mint family (predatory wasps and flies) – Daisy, chamomile, zinnia, echinacea, spearmint, catnip • Thyme, rosemary, clover – Bees, wasps, ground beetles Some Organic Insecticides • Entrust (Spinosad) – Microbial fermentation product – Targets: caterpillars, thrips, leafminers, some beetles – Soft on natural enemies, but toxic to bees – $550/lb • 1 gram/5 gal • 450 tanks = $1.20 each Bacillus thuringiensis – BT kurstaki and aizawai • Controls caterpillars – BT israelensis • Mosquito larvae – BT tenebrionis • Beetle larvae – Insects must eat treated foliage • Good spray coverage – Better against small larvae Neem • Azadirachtin: extract from neem tree • Multiple modes of action, including repellency • Broad spectrum – Best against larvae – Also good on whiteflies,aphids Pyrethrin or Pyrethrum • Extract from flowers of pyrethrum daisy • Broad spectrum • Breaks down quickly Insecticidal Soap • Potassium salts of fatty acids • Acts by smothering and can break down insect cuticle • Best against soft bodied insects (aphids, whiteflies, mites) Kaolin Clay • Applied as a slurry before pests arrive • Physical barrier, deterrent, irritant • Mix well, remove sprayer filter • Must wash fruit Pepper and Garlic Sprays BT Garlic Pepper Karate Neem Control Cucurbit Pests Squash Bug Control • Crop rotation and sanitation are very important. Rotate next years crop to different area. • During the summer, adults tend to congregate under shelter at night. Place boards on the soil surface near the squash in the evening and the next morning collect and destroy the pest. • Destroy egg masses on the underside of leaves. • A parasitic fly, Trichopoda pennipes, affects adult squash bugs and several wasps parastize the eggs. Provide habitat for these in or near the field. • If squash bugs are a problem on your farm, avoid heavy mulch or no-till in susceptible crops such as zucchini. Squash bugs like shelter, and appear more numerous in reduced tillage or mulched crop systems. • Pyrethrin and Neem products Cucurbit Pests Squash Vine Borer Control • Winter squash, pumpkins and zucchini are particularly susceptible. Butternut squash (C. moschata) is resistant. • Soon after crop harvest, plow the vine debris deeply to bury over larvae. • Rotate fields. • In small plantings, it may be possible to manually remove the larvae. Find the sawdust-like frass on the affected plant stem, and then locate the larva by slicing lengthwise along the stem until you reach it. Destroy the larva, and then cover the slit stem area with soil. • Keep floating row covers in place after transplanting or direct seeding until flowering. Cucurbit Pests Cucumber Beetle Control • Crop rotation and sanitation are important. • Floating row covers are very effective for avoiding beetle damage. Remember to temporarily remove the covers periodically to weed early, and leave off permanently when the flowers appear to allow pollination. • Use of trap crops. Cultivars vary dramatically in their attractiveness to beetles. The inexpensive variety Dark Green Zucchini and Blue Hubbard squash are effective trap crops. • Yellow sticky cups or tape can trap adults. They should be replaced regularly as they become saturated with beetles and field debris. • Use transplants instead of direct seeding. They will be older when beetles arrive and therefore more tolerant, or you can plant later after peak beetle activity is over. Solanaceous Crop Pests CPB Control • Crop rotation • Propane flamer; young potato plants if infested • Mulch crops with straw or hay before adults arrive • Hand picking • Entrust, Neem Solanaceous Crop Pests Flea Beetle Control • • • • Row covers Spinosad Neem products Capsaicin gives some control (45% in one study). The product, Miller’s Hot Sauce™ is OMRI-approved and labeled for use on crop plants as a mammal repellant. If so used, it will also reduce flea beetle damage. • Pyrethrum: Pyganic™ has shown variable results • Kaolin clay (Surround™). Sweet Corn Pests Corn Earworm Control • Corn varieties with long, tight husks impede the entrance of the worm somewhat, but these provide only partial control. Varieties that have been reported to be less susceptible to damage include: Silver Queen, Stowell’s Evergreen, Viking RB, Supersweet JRB, Golden Bantam, Jubilee, Texas Honey June, and Bodacious. • Since the pest is usually not a problem until mid to late summer, planting early to schedule harvest before expected arrival of CEW and using short season varieties will help avoid injury. • BT and oil (Zea-Later); apply when silks reach full length • Spinosad Questions [email protected]