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Degree Days for Common Fruit & Vegetable Insect Pests

Common Vegetable Insects that can be monitored using degree days or indicator plants

Cabbage maggot
Cabbage maggot

Cabbage Maggot Degree Days

Base temperature = 43°F

  • 300; 1,476; 2,652 DD43 for 1st; 2nd; & 3rd generations flies
  • 1st generation eggs are laid when the common lilac is in full bloom
Colorado Potato Beetle

Colorado Potato Beetle (First gen), Degree Days

Base temperature = 50°F

  • Begin counting when first eggs appear
  • 1st instar larva at 185 DD50
  • 2nd instar larva at 240 DD50
  • 3rd instar larva at 300 DD50
  • 4th instar larva at 400 DD50
  • Pupa at 675 DD50
Striped asparagus beetle adult

Common Asparagus Beetle Degree Days

Base temperature = 50°F

  • Egg laying at 150 – 240 DD50
    (Amelanchier full bloom, redbud early to full bloom, Black Hills spruce bud caps splitting)
Western corn rootworm

Corn Rootworm Degree Days

Base temperature = 50°F

  • Adult beetles present at 1,300 DD50
    (Canada thistle seed ripe, Queen Anne’s lace early bloom)
European Corn Borer

European Corn Borer Degree Days

Base temperature = 50°F

  • 1st spring moths at 375 DD50
    (Spiraea x vanhouttei in full bloom)
  • 1st eggs at 450 DD50
    (Pagoda dogwood late bloom)
  • Peak spring moths at 631 DD50
    (Black locust full bloom)
  • 1st summer moths at 1,400 DD50
    (Mountain-ash fruit golden yellow, most Canada thistle seed ripe)
  • 1st eggs at 1,450 DD50
  • 1st egg hatch at 1,550 DD50
  • Peak summer moths at 1,733 DD50
  • Summer treatment period at 1,550 – 2,100 DD50
    (Queen Anne’s lace full bloom – 1,500 to goldenrod early bloom – 2,100)
Fleabeetle

Fleabeetle Degree Days

Base temperature = 50°F

  • 150-200 DD50
    (Norway maple late bloom, Amelanchier blooming, redbud early bloom)
Imported cabbageworm larva

Imported Cabbageworm Degree Days

Base temperature = 50°F

  • Adult butterflies at 150-240 DD50
    (Amelanchier full bloom, redbud early to full bloom, Black Hills spruce bud caps splitting)
An onion maggot adult and onion maggot pupae

Onion Maggots

Base temperature = 40°F

  • 680, 1950, 3230 DD40 for 1st, 2nd, & 3rd generation flies
  • 1st generation eggs laid 230-280 DD40
Squash Vine Borer

Squash Vine Borer Degree Days

Base temperature = 50°F

  • Egg laying at 900-1,000 DD50
    (Chicory full bloom)

Seed Corn Maggot Degree Days

Base temperature = 39°F

  • 200, 600 for 1st and 2nd generation flies

Common Fruit Insects that can be monitored by degree days or indicator plants

Apple Maggot

Apple Maggot* Degree Days

Base temperature = 50°F

  • 1st adult fly emergence 900 DD50
  • 1st egg laying 1,100 DD50
  • Peak fly emergence 1,600 DD50
  • Peak egg laying 1,750 DD50
  • End of fly emergence 2,800 DD50

*These degree days assume normal soil moisture.  Under dry conditions, all apple maggot events will be delayed until the soil is moist.

Codling Moth

Codling Moth Degree Days

Base temperature = 50°F

  • 1st generation moth emergence 150 DD50
  • Eggs laid 250 DD50
  • 1st generation peak moth emergence 500 DD50
  • Peak egg laying 550 DD50
  • 2nd generation first moth emergence 1,150 DD50
  • 2nd generation peak moth emergence 1,600 DD50
  • 2nd generation peak egg laying 1,700 DD50

Obliquebanded Leafroller Degree Days

Base temperature = 43°F

  • 1st generation moth emergence 600 DD43
  • 1st generation peak moth emergence 800 DD43
  • 1st generation peak egg laying 1,250 DD43
  • 2nd generation moth emergence 2,050 DD43
  • 2nd generation first eggs laid 2,300 DD43

Author: Karen Delahaut, UW-Madison Fresh Market Vegetable Program
Revised:  8/6/2012
Item number:  XHT1087


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