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Overview of Insect Managementin Carrots
Overview of Insect Managementin Carrots
Brian A. NaultBrian A. NaultDepartment of EntomologyCornell UniversityNew York State Agricultural Experiment StationGeneva, NY 14456
Department of EntomologyCornell UniversityNew York State Agricultural Experiment StationGeneva, NY 14456
February 10, 2004February 10, 2004
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Pearl CreekPearl Creek MorganvilleMorganville
Carrot fields in Western New York - 2003Carrot fields in Western New York - 2003
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Pearl CreekPearl Creek
MaggotMaggot
Maggots, beetle larvae and disease
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Pearl CreekPearl Creek
Feeding injuryby cutworm, grub or mouse?
Feeding injuryby cutworm, grub or mouse?
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MorganvilleMorganvillePhysiological cracking and disease?Physiological cracking and disease?
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MorganvilleMorganville
Feeding injury by wireworm or grub?Feeding injury by
wireworm or grub? Pythium sp.
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QuestionsQuestions
! Was carrot weevil and/or carrot rustfly infesting the carrots?
! Did earlier damage by carrot weeviland/or carrot rust permit secondarypests and pathogens to establish?
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Carrot Weevil, Listronotus oregonensisCarrot Weevil, Listronotus oregonensis
!Adults overwinter in or near carrot fields
!Colonize fields in mid-May – late June, often along field edges
!Eggs laid in petioles or crown
!Oviposition scars about 1 mm
!Larva tunnels in root
!Another generation in late August
AdultAdult
ScarScar
LarvaLarva
Torres et al.
Torres et al.
Grafius
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Carrot Weevil DamageCarrot Weevil Damage
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Managing Carrot Weevil in CarrotManaging Carrot Weevil in Carrot
! Crop rotation (> 1 mile)
! Sanitation (destroy crop residue after harvest)
! Insecticides- Baythroid 2 (2.8 fl oz/acre)- Asana XL (9.6 fl oz/acre)
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Scouting for Carrot Weevil in CarrotScouting for Carrot Weevil in Carrot
1) Trap for adults
2) Monitor carrot pieces for scars
Action threshold is> 25% of root pieces withpunctures
3) Monitor plants for oviposition scars/punctures
Action threshold is > 1% infested plants
Stevenson and Chaput
Simonet
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Carrot Rust Fly, Psila rosae
!Adults overwinter near carrot fields
!Colonize fields in mid-May – late June
!Eggs laid on ground at base of plants
!Larva tunnels in root
!Two to three generations per year
Stevenson and Chaput
Stevenson and Chaput
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Carrot Rust Fly Damage
Stevenson and Chaput
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Managing Carrot Rust Fly in CarrotManaging Carrot Rust Fly in Carrot
! Crop rotation (> 1 mile)
! Select fields not sheltered by trees
! Sanitation (destroy crop residue after harvest)
! Insecticide- D.z.n. diazinon (4 lb or 1.5 oz/1,000 sq ft)
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Scouting for Carrot Rust Fly in CarrotScouting for Carrot Rust Fly in Carrot
1) Trap for adults- place along fieldedges
- place next to woods
Stevenson and Chaput
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Aster Leafhopper, Macrosteles quadrilineatus
!Overwinter as eggs in grain cropsor migrate from southern US
!Eggs hatch in early May
!Adults migrate into carrot fieldsin early May
!Two to five generations per year
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Aster YellowsAster Yellows! Adults transmit a phytoplasma
that causes aster yellows
! Adult must feed for a prolongedperiod to acquire phytoplasma
! Phytoplasma must circulate andreplicate for 18 to 20 d before adult becomes infective
! Adult must feed for a prolonged period to successfully transmit
! Three weeks for symptoms toappear
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Managing Aster Leafhopper in CarrotManaging Aster Leafhopper in Carrot
! Resistant varieties
! Insecticides- Baythroid 2 (2.8 fl oz/acre)- Asana XL (9.6 fl oz/acre)
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Scouting for Aster Leafhopper in CarrotScouting for Aster Leafhopper in Carrot1) Sweep for adults
2) Aster yellows index threshold = percentage of infected adults x leafhoppers per 100 sweeps
50 for susceptible varieties (e.g., 5% x 10 hoppers)75 for intermediate varieties100 for resistant varieties
Note: Conservative estimate is 5% infected adults, but >20% infected can occur. PCR now being used to estimate % infected adults.
3) No spray 3 weeks before harvest, because symptoms take 3 weeks to develop