Tree and Shrub Pests

WI-MN Cooperative Extension Agricultural Weather Page

Introduction

Development of tree and shrub pests can be estimated using a Modified base 50 F degree-day calculation. For these pests the degree-day summation is started well before the growing season.

The map below represents the accumulation of degree days for any given location in Wisconsin. A degree day is a unit of heat for each degree above the base temperature in a 24 hour period. This map uses a base temperature of 50 degrees F and begins calculating degree days from January 1st of the current year. Locate your location on the map and see what color corresponds with that location. Then, find that color in the color bar below the map to determine how many degree days have accumulated for your location since January 1st.

Degree day accumulations can be used to determine distinct phenological events such as when specific plants will bloom, when to plant vegetables, and when insect pest outbreaks will occur.

Schedule

Map is updated daily at about 11:30 am, from mid-April through July, depending slightly on the season.

Download the Image in Black and White

For further information on tree and shrub pests in Wisconsin,
contact Karen Delahaut of the Dept. of Horticulture, Univ. of Wisconsin-Madison
Karen Delahaut, kadelaha@facstaff.wisc.edu

For further information on this page,
contact Bill Bland at the Dept. of Soil Science, Univ. of Wisconsin-Madison
Bill Bland, wlbland@facstaff.wisc.edu