Title: Vegetable Insect Management PSS 124 Vegetable Crop Production
1Vegetable Insect ManagementPSS 124 Vegetable
Crop Production
- Jon P. Turmel, State Entomologist
- VT Agency of Agriculture
- Waterbury, Vermont
- November 30, 2006
2Transplants 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
3Aphids
green peach
foxglove
melon
potato
4Aphids
- High Fecundity Rates Explosive
Parthenogenetically, paedogenesis, sexual - Vectors
- Oviparous, viviparous
- Resistance increased production of an enzyme
5Aphid Morphology
6Aphid MorphologyTubercles
7Aphids
Tended by ants
Vectoring potato X virus
Sooty mold
Root aphids
8Aphid Parasitoids
9Aphid predators
flower fly Adult syrphid
Adult lady bird beetles
Syrphid larva
Lady bird beetle larva
10Crucifer Insect Pests
- Cabbage Maggot
- Cabbage Aphids
- Lepidopteran complex
- Diamondback Moth
- Imported cabbageworm
- Cabbage Looper
-
11Cabbage MaggotDelia radicum (L.)
12Cabbage 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
13Cabbage MaggotManagement
- Monitor using yellow-pan water traps
- 200 GDD
- Full bloom of Serviceberry, McIntosh and Cortland
apples
14Cabbage 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)
15Cabbage 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
16Lepidopteran ComplexDiamondback Moth, Imported
Cabbageworm and Cabbage Looper
Diamondback moth adult
Imported cabbageworm adult
Cabbage looper adult
17Diamondback 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
18Diamondback mothdamage
19Imported CabbagewormPieris rapae
egg
hatching
4-8 days
pupa
larva
24-31 days
8-20 days
Overwintering stage
20Imported Cabbagewormdamage
broccoli
cabbage
21Cabbage 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
22Cabbage Looperdamage
cabbage
broccoli
23Lepidopteran complexmanagement
- 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
24Potato Insect Pests
- Aphids green peach, potato, foxglove,
buckthorn, melon - Colorado Potato Beetle
- Potato leafhopper
25Colorado 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
26Colorado Potato Beetle
Adult feeding
Female laying eggs
Newly hatched eggs
Larval feeding
27Colorado 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
28Colorado 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
29Colorado Potato BeetleAction Threshold
Determination
- Walk the field in a V, W or X pattern
- Select 50 potato stalks at random intervals
- Count adults, large larvae (gt1/2 grown), small
larvae (lt 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
30Colorado 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
31Colorado Potato BeetleUse of Bacillus
thuringiensis tenebrionis
- 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!
32Potato leafhopperEmpoasca fabae
33Potato Leafhopper
adult
adult
nymph
adult
34Potato 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
35Potato 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
361 Enemy (In my humble opinion)
37Tarnished Plant BugLygus lineolaris (Palisot de
Beavois)
38Tarnished Plant Bug
- Feeds on over 300 different plants (gt50 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
39Tarnished Plant Bug
egg
nymph
40Bio-control
Peristenus digoneutis
41Tarnished Plant BugDamage
Celery
Tomato
Amaranth
Eggplant
42Tarnished Plant Bug Damage in Strawberry
43Corn Insect Pests
- European Corn Borer
- Corn Earworm
- Northern/Western Corn Rootworm
- Fall Armyworm
- Black Cutworm
- Common Armyworm
44European 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
45European Corn Borerdamage
Bell pepper
beans
popcorn
wheat
46European Corn Borereggs
black headed stage
egg mass on corn leaf
newly hatching eggs
47European Corn Borerlarvae
5 instars
1st instar feeding
larval feeding on ear
48European Corn Borer
larval tunnel in midrib
shot holes
larval tunnel in stalk
larval tunnel in ear stalk
49European Corn Borer
Pupae in stalks
50European Corn BorerPlowing down in fallwas the
LAW!75 of the overwintering larvae in a corn
field can be eliminated
51European Corn BorerScouting
Pulling whorl
Unfolding whorl
Blacklight trap
Scouting for eggs
52European Corn Borer
- No need to survey before corn is knee high
because of the high concentration of DIMBOA-
kills young larvae
53European Corn Borer
- When corn is pretassel and 15 of these young
tassels show damage - Earlier treatments are of no value
- 2nd generation in mid-July to Sept. will attack
ears. Must protect developing ears
54European Corn Borer
Transgenic corn in same field
Conventional corn whorl damage
55Corn EarwormHelicoverpa 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
56Corn Earworm
Adult usually arrives mid-July
Eggs in silk for 3 days
pupae
Larva feeding for about one month
57Corn EarwormMonitoring for adults and treatment
schedule
Pheromone baited heliothis traps
Blacklight trap
58 59Any Questions?
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