In this section we will include information relevant to cranberry production. In particular, in each issue we will include information about the degree day accumulation for the cranberry plant and for Sparganothis fruitworm. In case you would like a refresher on growing degree days, in our next issue (on May 2nd), in the “General Information” section, we’ll include a summary of how degree days are calculated, and how using degree day models can improve production on your marsh.

Degree days accumulate differently depending on your individual microclimate, so the best prediction will come from monitoring your own marsh temperatures and calculating degree days accordingly. However, this is of course often unrealistic, and the next best thing is to use weather data from nearby weather stations. For this reason, we’ve included average degree day accumulations from across the state of Wisconsin. The maps below show the range of cumulative cranberry growing degree-days (GDD) and Sparganothis fruitworm degree-days (DD) throughout the state of Wisconsin so far this year:

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The table below will give you a more precise DD accumulation, and allow comparisons over the last couple of years of both plant and insect development. At this point in the year, both the plants and insects are silently accumulating DD. The plants are still in tight bud and Sparganothis fruitworm larvae are still overwintering.

If you would like to read more articles and find more information specific to cranberry production in Wisconsin, be sure to read the most recent Cranberry Crop Management Journal, also published by the University of Wisconsin-Extension. In the April 6, 2016 issue of the Cranberry Crop Management Journal you will find information about:

• Dew Point for Cranberry
• Early Season Grower Workshops on April 28th
• Grower Updates

This article was posted in Cranberry, WFN, Vol. 1-4 and tagged Cranberries, Degree Days, Elissa Chasen.