Vegetable Insect Management PSS 124 Vegetable Crop Production

1. Vegetable Insect ManagementPSS 124 Vegetable Crop Production Jon P. Turmel, State Entomologist VT Agency of Agriculture Waterbury, Vermont November 30, 2006

2. Transplants in the Greenhouse • Aphids – Melon, Potato, Foxglove, Green Peach • Dipterans – Fungus gnat, Shore fly, Humpbacked fly, Moth fly, Leafminer • Mites – Two-spotted spider, Cyclamen • Whiteflies – Greenhouse, Silverleaf aka. Sweetpotato aphid

3. Aphids green peach foxglove melon potato

4. Aphids • High Fecundity Rates: “Explosive” Parthenogenetically, paedogenesis, sexual • Vectors • Oviparous, viviparous • Resistance – increased production of an enzyme

5. Aphid Morphology

6. Aphid Morphology“Tubercles”

7. Aphids Tended by ants Vectoring potato X virus Sooty mold Root aphids

8. Aphid Parasitoids

9. Aphid predators “flower fly” Adult syrphid Adult lady bird beetles Syrphid larva Lady bird beetle larva

10. Crucifer Insect Pests • Cabbage Maggot • Cabbage Aphids • Lepidopteran complex * Diamondback Moth * Imported cabbageworm * Cabbage Looper

11. Cabbage MaggotDelia radicum (L.)

12. Cabbage Maggotlife cycle • Overwinters as a pupa and emerges in mid-May • Prefers cool, moist weather • First generation most damaging • 2-3 generations/year • Larva completes cycle in 3 weeks • Feeds on all crucifers, beets, celery and onion Adult

13. Cabbage MaggotManagement • Monitor using yellow-pan water traps • 200 GDD • Full bloom of Serviceberry, McIntosh and Cortland apples

14. Cabbage MaggotManagement • Protection of roots and stems • Insecticide application as drench pre or post planting • Drench (2-3) at five week intervals • In furrow granular • Spunbonded row covers (rotated only)

15. Cabbage aphids • Aggregated vs uniform • No threshold at this time but when head is formed the threshold is zero • Serious vector • Selective insecticides • Selective non-target insecticides • Check for parasite pop. • Turnip-light oil reduces mosaic virus transmission

16. Lepidopteran ComplexDiamondback Moth, Imported Cabbageworm and Cabbage Looper Diamondback moth adult Imported cabbageworm adult Cabbage looper adult

17. Diamondback MothPlutella xylostella (L.) • Overwinters ? • Not known to be a vector • Larva = 4 instars in 10-14 days • Pupa = 14 days • Female lays 160 eggs in 2 weeks larva pupa

18. Diamondback mothdamage

19. Imported CabbagewormPieris rapae egg hatching 4-8 days pupa larva 24-31 days 8-20 days Overwintering stage

20. Imported Cabbagewormdamage broccoli cabbage

21. Cabbage LooperTrichoplusia ni (Hubner) Eggs hatch in 3-4 days As a pupa for about 2 weeks Larva have 5 instars in 3 weeks, most damage is done in last 2 instars does not overwinter in VT adult

22. Cabbage Looperdamage broccoli cabbage

23. Young plants = 35% infested More mature = 20% 10-15% on kale, collards and mustard Diamondback has become resistant, alternate between effective treatment High volumes give better results (50 gal/A) Bt kurstaki, higher rate in cool conditions Bt aizawai works better on resistant DBM MUST alternate with synthetic insecticide or spinosad (aerobic fermentation by product of a soil bacterium) Avoid southern transplants Lepidopteran complexmanagement

24. Potato Insect Pests • Aphids – green peach, potato, foxglove, buckthorn, melon • Colorado Potato Beetle • Potato leafhopper

25. Colorado Potato BeetleLeptinotarsa decemlineata • Overwinters as an adult in and around potato fields • 2 generations per year with a third in some years • Both adult and larva feed • Female lays 300-500 eggs • Implicated as a vector but not yet confirmed larval feeding larva

26. Colorado Potato Beetle Adult feeding Female laying eggs Larval feeding Newly hatched eggs

27. Rotate to nonhost crops. This includes overwintering sites that border previous season plantings Alternate different groups of insecticides throughout the season Use mechanical barriers such as trench traps and/or trap crops Determine Action Thresholds. Crop can withstand 15% defoliation without effecting yields None of the present commercial cultivars of potato is resistant to the CPB Biocontrol including insects, parasitoids and predators Colorado Potato Beetle Management

28. Colorado Potato BeetleTrench Trap • Plastic lined trench trap • Place next to overwintering areas at least one week prior to adult emergence • 1-2 feet deep and 6-24 inches wide at top • U or V shaped with walls 65-90 degree slope

29. Walk the field in a ‘V’, ‘W’ or ‘X’ pattern Select 50 potato stalks at random intervals Count adults, large larvae (>1/2 grown), small larvae (< half grown) Compare counts to the table (on next slide) If numbers is high, treatment is warranted If low, no treatment If between, no treatment but re-check in 3-5 days Colorado Potato BeetleAction Threshold Determination

30. Colorado Potato BeetleAction Thresholds* Life Stage Number of CPB per 50 Stalks Low High Adult Small Larvae Large Larvae 15 or fewer 25 or more 75 or fewer 200 or more 30 or fewer 75 or more *Do not apply to B.t. products and are for midseason. Late season plants can tolerate more defoliation without affecting yields

31. Most effective against 1st and 2nd instar. First spray one-3 days after there is one or more egg masses per lant and 30% have hatched If densely populated and eggs are hatching continuously, reapply after 5-7 days Or, wait for later instars to appear, treat with a single application of Provado or SpinTor the start your application a week later. Death with Bt may take up to 5 days but feeding ceases within one hour. Be patient! Colorado Potato BeetleUse of Bacillus thuringiensis tenebrionis

32. Potato leafhopperEmpoasca fabae

33. Potato Leafhopper adult adult nymph adult

34. Potato Leafhopper • Overwinters along the Gulf Coast on southern pine • Moves north on storm fronts and arrives in VT mid-June • Very low numbers can cause significant crop losses • Host of over 100 braod-leaved plants

35. Potato Leafhopper • Both nymphs and adults cause damage • No disease is known to be transmitted by the potato leafhopper • Causes “hopper burn” • Threshold is 10 nymphs per 100 plants. • Currently, no cultural or biological controls are available sweeping hopper burn

36. #1 Enemy (In my humble opinion)

37. Tarnished Plant BugLygus lineolaris (Palisot de Beavois)

38. Tarnished Plant Bug • Feeds on over 300 different plants (>50 of economic importance) • Introduces a toxic saliva into the plant while feeding • Causes leaf distortion, ‘black joint’, scarring, discoloration, bud abortion, dwarfed and pitted fruit

39. Tarnished Plant Bug egg nymph

40. Bio-control Peristenus digoneutis

41. Tarnished Plant BugDamage Celery Tomato Amaranth Eggplant

42. Tarnished Plant Bug Damage in Strawberry

43. Corn Insect Pests • European Corn Borer • Corn Earworm • Northern/Western Corn Rootworm • Fall Armyworm • Black Cutworm • Common Armyworm

44. European Corn BorerOstrinia nubilalis • Feeds on over 200 wild and herbaceous plants • Different strains cause different types of damage to corn • Vector of shank, stalk and ear rot fungi • 1-2 generations/year

45. European Corn Borerdamage Bell pepper beans popcorn wheat

46. European Corn Borereggs black headed stage egg mass on corn leaf newly hatching eggs

47. European Corn Borerlarvae 5 instars 1st instar feeding larval feeding on ear

48. European Corn Borer larval tunnel in midrib shot holes larval tunnel in stalk larval tunnel in ear stalk

49. European Corn Borer Pupae in stalks

50. European Corn BorerPlowing down in fall…was the LAW!75% of the overwintering larvae in a corn field can be eliminated