Degree-day Updates & Forecast

Anthony Hanson, Extension Post-Doctoral Associate, UMN Extension IPM Program, Dept. of Entomology, Univ. of Minnesota, St. Paul campus

European Corn Borer

Beginning with the 2018 growing season, European corn borer (ECB) degree-days (DD) will be provided on VegEdge to assist growers, processors and agronomists with key information on expected timing of each major life stage, e.g., timing of first moth emergence, peak moth flight, first egg-lay, etc. The first DD maps are being provided for the bivoltine (2-generation) strain. We use a Modified DD model with lower (50F) and upper thresholds (86F), and January 1st as the start date; this is similar to the original model developed at the University of Wisconsin (Dr. J.W. Apple, Extension Entomology, UW-Madison). Degree-days were calculated from current and eight-day forecast daily temperature data provided by the U.S. National Phenology Network.

ECB, 1st generation (bivoltine strain), Degree-day updates (6/13/18)

Current Degree Days
Current degree-days, since Jan 1st, using Modified, Max-Min method

Forecasted Degree Days
Degree-day Forecast, using Modified, Max-Min method

Seed Corn Maggot

Degree-day models for seed corn maggot are used to predict peak emergence for each generation when risk of damage in highest. These maps use a modified simple degree-day calculation of lower (39°F) and upper (84.2°F) thresholds with a Jan. 1 biofix date modified from Funderburk et al. (1984. Environ. Entomol. 13: 105-109). Daily maximum temperatures that exceed the upper threshold are set to the upper threshold, and negative daily degree-days are set to zero. Degree-days were calculated from current and eight-day forecast daily temperature data provided by the U.S. National Phenology Network.

SCM, Degree-day updates (6/15/18)

SCM Current Degree-days
Current degree-days, since Jan 1st, using Modified, Max-Min method

SCM Forecasted Degree-days
Degree-day Forecast, using Modified, Max-Min method