Degree days - Crops in Good Condition Despite Cool Temperatures

June 3, 2009

by Rich Pope, Corn and Soybean Initiative

The 2009 growing season finished off May a bit cool, with degree day accumulations for only one of the nine crop reporting districts, west central, besting its long-term average. May was marginally cooler in the east, although that is not a problem, and crops are off to a great start statewide. 

Degree day map for May 31

As we projected, black cutworm larvae were large enough to damage corn in southern Iowa by May 25 - with light black cutworm feeding on corn noted last week in southeast and south central Iowa.  These infestations have been light and sporadic, but they warrant monitoring.

Weedy fields are a concern statewide. Timely and appropriate weed management, especially in no-till fields, can be economically significant.


Rich Pope is a program specialist with responsibilities with Integrated Pest Management. Pope can be contacted by email at or by calling (515)294-5899.

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