WSU Whatcom County Extension

Spotted Wing Drosophila

WSU Whatcom County Extension                         

Degree Day Model


Most insects develop at different rates depending on temperature which allows the use of degree days (a measurement of temperature above a certain threshold over time) to predict when certain life stages will occur. A degree day model, or phenology model, for Spotted Wing Drosophila has been developed by researchers at Oregon State University. This model will use current temperature data and weather forecasts and compare to 30 year averages to predict when SWD will begin egg laying, emerge as adults, and transfer to the next generation.

The degree day model can be accessed here:

Leonard Coop and Amy Dreves published an article on using the degree day model (pdf - link to article) in the 2013 March edition of the Whatcom Ag Monthly.

Below is a summary, updated twice per week, of the degree day model for locations in Whatcom and Skagit counties. The map shows weather stations from where the model is calculated. The table shows current degree day (dd) accumulation, dd compared to last year, and predictions of timing of phenological events for SWD at each location. The chart at the bottom shows a comparison of degree days accumulated this year between stations in Whatcom and Skagit Counties.


Whatcom County:

Whatcom County SWD Map



Skagit County:

Skagit County SWD Map





Heading using the h3 tag

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

WSU Whatcom County Extension • 1000 N. Forest St., Bellingham, WA 98225 • (360) 778-5800 •