1. Insect Control in the Organic Vegetable Garden

2. 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

3. Organic Control ‘Toolbox’ Example for Cucumber Beetle
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
Source: Univ. of Kentucky Entomology

4. 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

5. Choose Less Susceptible Varieties
Hairy-leaf varieties
Tight husked corn
Corn earworm
Virus-resistance
GMO
Tomatoes
Cucurbits
Squash vine borer
ATTRA publication

6. 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

7. 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

8. Keeping Records

9. 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

10. Sampling Equipment

11. 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?

12. Evidence of Natural Enemies

13. 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%

14. Insect Identification
ID insects at least to Order, and if possible to Family

15. 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

16. Key Insect Orders Orthoptera: Grasshoppers and Crickets
Hemiptera: True Bugs
Thysanoptera: Thrips

17. Key Insect Orders
Coleoptera: Beetles
Diptera: Flies

18. Key Insect Orders Homptera: Aphids, whiteflies
Lepidoptera: Butterflies, moths
Hymenoptera: Ants, bees, wasps

19. Arachnids: Mites and Spiders
Spider mites
Spiders

20. Insect Metamorphosis Incomplete (12%) Complete (88%) Grasshoppers
True bugs
Aphids, thrips
Complete (88%)
Beetles
Flies
Ants, wasps, bees

21. Tips to Identify Larvae
Lepidpotera (Caterpillars)
Coleoptera: Beetles

22. Tips to Identify Larvae
Hymenoptera: Wasps
Diptera: Flies

23. Quiz: What are these?
Hint: One on top will undergo complete metamorphosis; One on bottom; incomplete metamorphosis

24. 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

25. Mulches Organic Straw mulch
Retains soil moisture, lowers soil temperature
Habitat for predators (and some pests)
Excellent for potatoes, cucurbits

26. Mulches Plastic Black Reflective: Speeds early season crop growth
Repels thrips, aphids
Reduces spread of viruses

27. 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
Experiments in South Carolina showed that rye planted between rows of melon reduced the incidence of Watermelon Mosaic Virus. The cover crop made the melon plants less attractive to aphid vectors of the disease.
% Plants Infected with WMV

28. 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

29. Exclusion

30. High Pressure Spray (Aphids, mites, whiteflies)
Water Wand: Cecil Stokes;

31. 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

32. 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)

33. 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

34. 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

35. 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

36. Neem Azadirachtin: extract from neem tree
Multiple modes of action, including repellency
Broad spectrum
Best against larvae
Also good on whiteflies,aphids

37. Pyrethrin or Pyrethrum
Extract from flowers of pyrethrum daisy
Broad spectrum
Breaks down quickly

38. Insecticidal Soap Potassium salts of fatty acids
Acts by smothering and can break down insect cuticle
Best against soft bodied insects (aphids, whiteflies, mites)

39. Kaolin Clay Applied as a slurry before pests arrive
Physical barrier, deterrent, irritant
Mix well, remove sprayer filter
Must wash fruit

40. Pepper and Garlic SpraysBT
Garlic
Pepper
Karate
Neem
Control

41. Cucurbit Pests

42. 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

43. Cucurbit Pests

44. 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.

45. Cucurbit Pests

46. 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.

47. Solanaceous Crop Pests

48. CPB Control Crop rotation
Propane flamer; young potato plants if infested
Mulch crops with straw or hay before adults arrive
Hand picking
Entrust, Neem

49. Solanaceous Crop Pests

50. 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™).

51. Sweet Corn Pests

52. 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

53. Questions zehnder@clemson.edu