Vegetable Pest Management Chuck Marr K-State Research & Extension Horticulture

1. Vegetable Pest Management Chuck Marr K-State Research & Extension Horticulture

2. Elements of vegetable pest control practices • Proper identification of problem early enough to control • Timing of control measures at critical time • Thorough complete application- repeated if necessary

3. Natural insecticides Biological pest control materials Row covers (exclusion) Soaps and oils Sulfur (not in heat) Rotation and intervals Companion plantings Hand removal? Light traps ‘Alternative’ control measures Effective alternatives Questionable

4. IR-4 (Pesticides for Minor Use Crops) • Critical crop pest control needs matched with potential pesticides • Government grant sponsors field/residue testing • Pesticide labels issued • Traditional pest control materials • Ultra-low application rate materials • Bio-pesticides

5. Cabbage Worms • Imported cabbage worm • Cabbage looper • Diamondback moth All develop from eggs laid on underside of cabbage leaves-developing into worms or larvae that feed on leaves/heads.

7. ‘Wetting agent’ Spreader-Sticker Liquid soap

8. Severe worm feeding reduce leaf area of plant appear in heads or processed product

9. Corn Earworm • (also known as the tomato fruitworm) • Feeds on ends of sweetcorn ear • When corn is husked, worms fall out • No tolerance in processed product and very little tolerance in fresh product in grocery stores

10. Ear just visible Silking Mid silk

11. Silking to harvest = 21 days (3 weeks) Silking until silk start to dry at tips about 12-14 days Silks fully extended and starting to dry at tips Some varieties produce colored silks

12. Corn earworm moth is a night-flying dingy colored moth that lays eggs on developing silks of corn Larvae hatch, crawl down the silk and enter the ear. Prevailing weather patterns and air currents cause ‘waves’ or ‘cycles’ of worms to fly into our area. Typically about7-8 Waves or cycles/yr

13. Moths seek out some nice juicy silks and deposit eggs. Earworms are cannibalistic- multuple worms may crawl into the ear but they eat each other so only one worm remains….

14. As ear develops, silks extend or grow-exposing new silks each day. Repeated insecticide applications during silking- every 2-3 days until silks start to dry (about 12-14 days into ear development) 21 days from silking to harvest Silking Silks Start to Dry Harvest

15. Monitoring earworm flights using a phermone lure inside a ‘sticky’ or cone trap. Male moths fly up into cone made of netted material-caught in the top chamber. Counted each day to monitor flights.

16. Phermone lure attached to a ‘delta’ sticky trap. Folded to protect it from rain, dust and other contaminants.

17. Tomato Disease Problems • Fusarium wilt – races 1,2 (and now 3) • Leaf ‘blight’ • Septoria leaf spot • Early blight • Tomato spotted wilt virus

18. Fusarium wilt in tomato. No known control. Persists for 8-12 years. There are 2 strains or races F1 and F2. Need both resistance (A new strain F3 has been discovered in the deep south)

19. Fusarium wilt in tomatoes Specific to tomatoes (Fusarium oxysporum lycopersicii) No known control Resistance in varieties V= verticillium wilt F1,2=fusarium wilt N=nematodes

20. Leaf blight (Early Blight and Septoria Leaf Spot) is a different story. There is some resistance available but hasn’t proven to be very effective in the field. Both are foliar fungus diseases-spores develop on leaves and don’t enter the roots of the plant.

21. Tomato Spotted Wilt (TSW) Virus Stunted plants, purplish color. Mottled, marbled fruit Spread by western flower thrips-primarily in greenhouse or transplants.

22. Mites (Spider Mites) Build up in hot, dry conditions Small- on undersides of leaves

23. When severe, may see webbing on leaves. Often confused with heat or drought stress. Plants seem to ‘fade away’.

24. Dealing with mites • Develop in ‘spots’ or areas in the field/garden • Control early • Miticides • Kelthane • Dicofol (Cygon) • Soaps (multiple applications) • Sevin will cause buildup (kills predatory mites)

25. Vine Crops Cucumber Muskmelon Watermelon Pumpkin Squash Gourds All produce a similar flavor compound ‘cucurbitacin’. Attracts certain insects. Share some common disease and insect problems.

26. Powdery Mildew Reduce yields 30-50% Difficult to control Resistance now available in a few varieties of pumpkins. Strong resistance in cucumbers and muskmelon. Watermelon doesn’t get. Resistant Susceptible

27. Begins about 2 weeks after full vine cover- usually 7-14th of August. Resistance available in Cucumber (strong) Muskmelon (strong) Pumpkin (some) Watermelon (don’t get) Squash (very sporadic)

28. Bacterial wilt (cucumber and muskmelon) Bacteria carried by cucumber beetle. Injected into plants. Develops in vascular tissues-plugging the stems.

29. Fusarium wilt or blight in pumpkins Pumpkins go out fairly early in season Dark discoloration in stem Long (3 yr) rotations and avoid root injury or wet spots

30. Squash bugs- a grey shield-shaped bug that sucks juices from the plant and releases a toxin that causes wilting and death.

33. Squash Bug Population Dynamics • Overwinter as adults • Begin to lay eggs in late May 1 adult • First generation mid June-July 500-600 adults • Second generation lay eggs • Second generation mid Sept-Oct 62,000 adults

34. Strategies for Squash Bug Control • Reduce overwintering adults (hibernation places) • Spray only after the hatch • Control in 1st generation • Remove vines as soon as fruit are mature • Vine removal prevents overwintering and removes hibernation places

35. Microdochium Blight First appeared in the mid 97’s in eastern and midwest states Typical fungicides controls don’t work very well. Lesions on fruit and stem

36. Pumpkin Yellows or “Yellow Stem”-first seen in 2000 No brown discoloration in stem. Plugging of phloem conducting cells in root. Little known at present-suspected carrier are squash bugs.

37. Information from K-State Research and Extension • http://www.oznet.ksu.edu/horticulture • Pest Control in Vegetable Gardens • Alternative Pest Control Measures in Gardens • Common Horticultural Plant Problems (single page ‘fact sheets’)

38. Kansas State Research & Extension “Knowledge for Life”