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

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Presentation on theme: "Vegetable Insect Management PSS 124 Vegetable Crop Production Jon P. Turmel, State Entomologist VT Agency of Agriculture Waterbury, Vermont November 30,"— Presentation transcript:

1 Vegetable Insect Management PSS 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 peachfoxglove 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 Adult lady bird beetles Lady bird beetle larva “flower fly” Adult syrphid Syrphid larva

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

11 Cabbage Maggot Delia radicum (L.)

12 Cabbage Maggot life 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 Maggot Management Monitor using yellow-pan water traps 200 GDD Full bloom of Serviceberry, McIntosh and Cortland apples

14 Cabbage Maggot Management 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 Complex Diamondback Moth, Imported Cabbageworm and Cabbage Looper Diamondback moth adult Imported cabbageworm adult Cabbage looper adult

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

18 Diamondback moth damage

19 Imported Cabbageworm Pieris rapae egg hatching larva pupa Overwintering stage 4-8 days 8-20 days days

20 Imported Cabbageworm damage broccoli cabbage

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

22 Cabbage Looper damage cabbagebroccoli

23 Lepidopteran complex management 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

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

25 Colorado Potato Beetle Leptinotarsa decemlineata Overwinters as an adult in and around potato fields 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 eggs Implicated as a vector but not yet confirmed larva larval feeding

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

27 Colorado Potato Beetle Management 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

28 Colorado Potato Beetle Trench 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 degree slope

29 Colorado Potato Beetle Action Threshold Determination 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 ( 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

30 Colorado Potato Beetle Action Thresholds* Life StageNumber of CPB per 50 Stalks LowHigh 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 Colorado Potato Beetle Use of Bacillus thuringiensis tenebrionis Most effective against 1 st and 2 nd 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!

32 Potato leafhopper Empoasca fabae

33 Potato Leafhopper 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 Bug Lygus 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 Bug Damage 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 Borer Ostrinia 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 Borer damage beans Bell pepper popcorn wheat

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

47 European Corn Borer larvae 5 instars 1 st instar feeding larval feeding on ear

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

49 European Corn Borer Pupae in stalks

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

51 European Corn Borer Scouting Pulling whorl Unfolding whorl Scouting for eggs Blacklight trap

52 European Corn Borer No need to survey before corn is knee high because of the high concentration of DIMBOA- kills young larvae

53 European Corn Borer When corn is pretassel and 15% of these young tassels show damage Earlier treatments are of no value 2 nd generation in mid- July to Sept. will attack ears. Must protect developing ears

54 European Corn Borer Conventional corn whorl damage Transgenic corn in same field

55 Corn Earworm Helicoverpa zea aka. Heliothis zea Native to the Americas Most destructive after E. Corn Borer Does not overwinter in VT Molds become toxins Larvae may destroy silk before pollination is complete $$$ when severe

56 Corn Earworm Adult usually arrives mid-JulyEggs in silk for 3 days pupaeLarva feeding for about one month

57 Corn Earworm Monitoring for adults and treatment schedule Pheromone baited heliothis traps Blacklight trap

58

59 Any Questions?

60


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