Important Insect Plant Pests and their Hosts in Florida (Vegetable Crops)
Jon Turmel-Vegetable Insect Management
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Transcript of Jon Turmel-Vegetable Insect Management
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Vegetable Insect Management
PSS 124 Vegetable Crop ProductionJon P. Turmel, State Entomologist
VT Agency of Agriculture
Waterbury, Vermont
November 30, 2006
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Transplants in the Greenhouse
Aphids Melon, Potato, Foxglove, Green PeachDipterans Fungus gnat, Shore fly, Humpbacked fly, Moth fly, LeafminerMites Two-spotted spider, CyclamenWhiteflies Greenhouse, Silverleaf aka. Sweetpotatoaphid
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Aphids
green peach
foxglove
melon
potato
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Aphids
High Fecundity Rates: Explosive Parthenogenetically, paedogenesis, sexualVectorsOviparous, viviparousResistance increased production of an enzyme -
Aphid Morphology
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Aphid Morphology
Tubercles -
Aphids
Tended by ants
Vectoring potato X virus
Sooty mold
Root aphids
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Aphid Parasitoids
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Aphid predators
Adult lady bird beetles
Lady bird beetle larva
flower fly Adult syrphid
Syrphid larva
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Crucifer Insect Pests
Cabbage MaggotCabbage AphidsLepidopteran complex* Diamondback Moth
* Imported cabbageworm
* Cabbage Looper
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Cabbage Maggot
Delia radicum (L.) -
Cabbage Maggot
Overwinters as a pupa and emerges in mid-MayPrefers cool, moist weatherFirst generation most damaging2-3 generations/yearLarva completes cycle in 3 weeksFeeds on all crucifers, beets, celery and onion
life cycleAdult
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Cabbage Maggot
Monitor using yellow-pan water traps200 GDDFull bloom of Serviceberry, McIntosh and Cortland apples
Management -
Cabbage Maggot
Protection of roots and stems Insecticide application as drench pre or post plantingDrench (2-3) at five week intervalsIn furrow granularSpunbonded row covers (rotated only)
Management -
Cabbage aphids
Aggregated vs uniformNo threshold at this time but when head is formed the threshold is zeroSerious vectorSelective insecticidesSelective non-target insecticidesCheck for parasite pop.Turnip-light oil reduces mosaic virus transmission -
Lepidopteran Complex
Diamondback Moth, Imported Cabbageworm and Cabbage LooperDiamondback moth adult
Imported cabbageworm adult
Cabbage looper adult
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Diamondback Moth
Overwinters ?Not known to be a vectorLarva = 4 instars in 10-14 daysPupa = 14 daysFemale lays 160 eggs in 2 weeks
Plutella xylostella (L.)larva
pupa
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Diamondback moth
damage -
Imported Cabbageworm
Pieris rapaeegg
hatching
larva
pupa
Overwintering stage
4-8 days
8-20 days
24-31 days
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Imported Cabbageworm
damagebroccoli
cabbage
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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
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Cabbage Looper
damagecabbage
broccoli
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Lepidopteran complex
Young plants = 35% infestedMore mature = 20%10-15% on kale, collards and mustardDiamondback has become resistant, alternate between effective treatmentHigh volumes give better results (50 gal/A)Bt kurstaki, higher rate in cool conditionsBt aizawai works better on resistant DBMMUST alternate with synthetic insecticide or spinosad (aerobic fermentation by product of a soil bacterium) Avoid southern transplants
management -
Potato Insect Pests
Aphids green peach, potato, foxglove, buckthorn, melonColorado Potato BeetlePotato leafhopper -
Colorado Potato Beetle
Overwinters as an adult in and around potato fields2 generations per year with a third in some yearsBoth adult and larva feedFemale lays 300-500 eggsImplicated as a vector but not yet confirmed
Leptinotarsa decemlineatalarva
larval feeding
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Colorado Potato Beetle
Adult feeding
Newly hatched eggs
Female laying eggs
Larval feeding
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Colorado Potato Beetle Management
Rotate to nonhost crops. This includes overwintering sites that border previous season plantingsAlternate different groups of insecticides throughout the seasonUse mechanical barriers such as trench traps and/or trap crops Determine Action Thresholds. Crop can withstand 15% defoliation without effecting yieldsNone of the present commercial cultivars of potato is resistant to the CPBBiocontrol including insects, parasitoids and predators -
Colorado Potato Beetle
Plastic lined trench trapPlace next to overwintering areas at least one week prior to adult emergence1-2 feet deep and 6-24 inches wide at topU or V shaped with walls 65-90 degree slope
Trench Trap -
Colorado Potato Beetle
Walk the field in a V, W or X patternSelect 50 potato stalks at random intervalsCount adults, large larvae (>1/2 grown), small larvae (< half grown)Compare counts to the table (on next slide)If numbers is high, treatment is warrantedIf low, no treatmentIf between, no treatment but re-check in 3-5 days
Action Threshold Determination -
Colorado Potato Beetle
Action 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
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Colorado Potato Beetle
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 hatchedIf 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!
Use of Bacillus thuringiensis tenebrionis -
Potato leafhopper
Empoasca fabae -
Potato Leafhopper
nymph
adult
adult
adult
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Potato Leafhopper
Overwinters along the Gulf Coast on southern pineMoves north on storm fronts and arrives in VT mid-JuneVery low numbers can cause significant crop lossesHost of over 100 braod-leaved plants -
Potato Leafhopper
Both nymphs and adults cause damageNo disease is known to be transmitted by the potato leafhopperCauses hopper burnThreshold is 10 nymphs per 100 plants. Currently, no cultural or biological controls are availablesweeping
hopper burn
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#1 Enemy
(In my humble opinion) -
Tarnished Plant Bug
Lygus lineolaris (Palisot de Beavois) -
Tarnished Plant Bug
Feeds on over 300 different plants (>50 of economic importance)Introduces a toxic saliva into the plant while feedingCauses leaf distortion, black joint, scarring, discoloration, bud abortion, dwarfed and pitted fruit -
Tarnished Plant Bug
egg
nymph
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Bio-control
Peristenus digoneutis
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Tarnished Plant Bug
DamageCelery
Tomato
Amaranth
Eggplant
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Tarnished Plant Bug Damage in Strawberry
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Corn Insect Pests
European Corn BorerCorn EarwormNorthern/Western Corn RootwormFall ArmywormBlack CutwormCommon Armyworm -
European Corn Borer
Feeds on over 200 wild and herbaceous plantsDifferent strains cause different types of damage to cornVector of shank, stalk and ear rot fungi1-2 generations/year
Ostrinia nubilalis -
European Corn Borer
damagebeans
Bell pepper
popcorn
wheat
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European Corn Borer
eggsblack headed stage
newly hatching eggs
egg mass on corn leaf
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European Corn Borer
larvae5 instars
1st instar feeding
larval feeding on ear
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European Corn Borer
shot holes
larval tunnel in midrib
larval tunnel in ear stalk
larval tunnel in stalk
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European Corn Borer
Pupae in stalks
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European Corn Borer
Plowing down in fallwas the LAW!
75% of the overwintering larvae in a corn field can be eliminated -
European Corn Borer
ScoutingPulling whorl
Unfolding whorl
Scouting for eggs
Blacklight trap
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European Corn Borer
No need to survey before corn is knee high because of the high concentration of DIMBOA- kills young larvae -
European Corn Borer
When corn is pretassel and 15% of these young tassels show damageEarlier treatments are of no value2nd generation in mid-July to Sept. will attack ears. Must protect developing ears -
European Corn Borer
Conventional corn whorl damage
Transgenic corn in same field
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Corn Earworm
Native to the AmericasMost destructive after E. Corn BorerDoes not overwinter in VTMolds become toxinsLarvae may destroy silk before pollination is complete$$$ when severe
Helicoverpa zea aka. Heliothis zea -
Corn Earworm
Adult usually arrives mid-July
Eggs in silk for 3 days
pupae
Larva feeding for about one month
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Corn Earworm
Monitoring for adults and treatment schedulePheromone baited heliothis traps
Blacklight trap
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Any Questions?