Resource for Tracking Growing Degree Days and Emerald Ash Borer
Posted: March 28, 2012
Black locust (Robinia pseudoacacia) flowers. Photo by John M. Randall, The Nature Conservance, Bugwood.org
We recently received information from Nick Kuhn, Community Forestry and Communications, at the Missouri Dept. of Conservation, about tracking growing degree days (GDD) in relation to scouting for adult emerald ash borers (EAB). There is a great resource that he provided which allows you to find the GDD for any zip code by using the Weather Channel’s web site.
To get GDD information for your location, enter the zip code. Select a base temperature of 50F for calculating degree days. Enter January 1 for the start date, and enter the previous day's date for the end date. The year should default to current year, and when you press “update” the calculator will provide the GDD for your location.
This is a great tool to use when monitoring for any turf or landscape pests. And if you’re concerned about looking for Emerald Ash Borer adults, adult emergence starts at 450-500 degree days (base 50) and peaks at 900-1100 degree days.
You can also use phenotypic indicators as a cue. EAB adults start to emerge roughly at the time of black locust bloom. Peak adult activity occurs around the time of catalpa bloom.
We need to be vigilant, since in the locations where EAB has been confirmed, it is apparent they have been there for a while.