Articles > Insects

Degree Days for Common Landscape Insect Pests

Black vine weevil
Black vine weevil

Karen Delahaut, UW-Madison Fresh Market Vegetable Program
Revised:  8/13/2012
Item 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
1st generation adults = 400-600 DD50
2nd generation adults = 900-1000 DD50

Bronze Birch Borer
Larvae = 400-500 DD50

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
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
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)
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
1st generation crawlers = 200-350 DD50
2nd generation crawlers = 1600-1700 DD50

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 XHT1085, XHT1086 and XHT1087, or contact your county Extension agent.

Additional Images


Download Article
This page is optimized for printing

Featured Articles by Season

Ask Your Gardening Question

If you’re unable to find the information you need, please submit your gardening question here:

Support Extension