University of Wisconsin Garden Fact Sheets
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Degree Days for Common Landscape Insect Pests

Authors: Karen Delahaut, UW-Madison Fresh Market Vegetable Program
Last Revised: 04/26/2004
X-number: XHT1088

Ash Borer
1st instar larvae = 275-500 DD50

Ash Plantbug
Nymphs = 100-200 DD50

Birch Leafminer
1st generation larvae = 275-500 DD50

Black Vine Weevil
Black Vine Weevil

 

Black Vine Weevil
1st generation adults = 400-600 DD50
2nd generation adults = 900-1000 DD50

 

 

Bronze Birch Borer
Larvae = 400-500 DD50

Cooley Spruce Gall Adelgid
Cooley Spruce Gall Adelgid

 

Cooley Spruce Gall Adelgid
Adults = 50-100 DD50
Egg hatch = 210 DD50
Galls forming = 250 DD50
2nd generation nymphs = 2800-3000 DD50

 

 

Cottony Maple Scale
Cottony Maple Scale

 

Cottony Maple Scale
Egg hatch = 850 DD50
Crawlers = 900-1200 DD50

 

 

Eastern Spruce Gall Adelgid
Adults = 50-100 DD50
Egg hatch = 90 DD50
1st instar larvae = 100 DD50
2nd generation nymphs = 2800-3000 DD50

Eastern Tent Caterpillar
Eastern Tent Caterpillar

Eastern Tent Caterpillar
Egg hatch = 50 DD50
1st instar larvae = 100 DD50
2nd instar larvae = 140 DD50
3rd instar larvae = 350 DD50
Adults = 725 DD50

 

 

Elm Leaf Beetle
Larvae = 400-500 DD50

Elm Sawfly
Larvae = 365 DD50

Euonymous Scale
Crawlers = 500-700 DD50

European Pine Sawfly
1st instar larvae = 50-100 DD50

European Pine Shoot Moth
Spring larvae active = 50-100 DD50
Adults = 900 DD50
Egg hatch = 200-100 DD50

Fall Webworm
Larvae = 850 DD50

Fletcher Scale
Adults = 100-200 DD50
Egg hatch = 600 DD50
Crawlers active = 900-1200 DD50

Gypsy Moth
Egg hatch = 100-200 DD50
Larvae = 200-350 DD50

Hawthorn Leafminer
Larvae = 275-500 DD50

Honeylocust Plantbugs
= 100-200 DD50

Imported Willow Leaf Beetle
= 200-350 DD50

Japanese Beetle
Adults = 900-1200 DD50

Mountain Ash Sawfly
= 500 DD50

Oystershell Scale (brown race)
Oystershell Scale (brown race)

 

Oystershell Scale (brown race)
Egg hatch = 265 DD50
1st generation crawlers = 275-500 DD50
2nd generation crawlers = 1600-1700 DD50

 

 

Oystershell Scale (grey race)
1st generation crawlers = 400-600 DD50

Pine Needle Scale
Pine Needle Scale

 

Pine Needle Scale
1st generation crawlers = 200-350 DD50
2nd generation crawlers = 1600-1700 DD50

 

 

 

Pine Spittlebug
Pine Spittlebug

 

Pine Spittlebug
1st generation egg hatch = 145 DD50
2nd generation egg hatch = 1500 DD50
2nd generation crawlers = 1500-1600 DD50

 

 

Spruce Spider Mite
= 100-200 DD50

Taxus Mealybug
= 275=500 DD50

Viburnum Crown Borer
1st instar larvae = 500-600 DD50

Zimmerman Pine Shoot Moth
1st generation larvae (1st instar) = 100 DD50
2nd generation larvae (1st instar) = 2700-2900 DD50

For more information on phenology:  See University of Wisconsin Garden Facts X1085, X1086 and X1087, or contact your county Extension agent.


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Thanks to Michelle Miller and Susan Mahr for reviewing this document.

A complete inventory of University of Wisconsin Garden Facts is available at the University of Wisconsin-Extension Plant Disease Diagnostics Clinic website: http://pddc.wisc.edu.