Authors: Karen Delahaut, UW-Madison Fresh Market Vegetable Program

Last Revised: 04/26/2004

D-number: XHT1088

Ash Borer
1st instar larvae = 275-500 DD₅₀

Ash Plantbug
Nymphs = 100-200 DD₅₀

Birch Leafminer
1^st generation larvae = 275-500 DD₅₀

 

Black Vine Weevil
1^st generation adults = 400-600 DD₅₀
2^nd 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
1^st instar larvae = 100 DD₅₀
2^nd instar larvae = 140 DD₅₀
3^rd 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
1^st generation crawlers = 275-500 DD₅₀
2^nd generation crawlers = 1600-1700 DD₅₀

 

 

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

 

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

 

 

 

 

Pine Spittlebug
1^st generation egg hatch = 145 DD₅₀
2^nd generation egg hatch = 1500 DD₅₀
2^nd 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.

This Fact Sheet is also available in PDF format:

© 2002 the Board of Regents of the University of Wisconsin System doing business as University of Wisconsin-Madison Division of Extension.

An EEO/Affirmative Action employer, University of Wisconsin-Madison Division of Extension provides equal opportunities in employment and programming, including Title IX and ADA requirements. This document can be provided in an alternative format by calling Brian Hudelson at (608) 262-2863 (711 for Wisconsin Relay).

References to pesticide products in this publication are for your convenience and are not an endorsement or criticism of one product over similar products. You are responsible for using pesticides according to the manufacturer’s current label directions. Follow directions exactly to protect the environment and people from pesticide exposure. Failure to do so violates the law.

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

A complete inventory of UW Plant Disease Facts is available at the University of Wisconsin-Madison Plant Disease Diagnostics Clinic website: https://pddc.wisc.edu.