Degree Days - Brisk, but Basically OK

May 19, 2009

by Rich Pope, Corn and Soybean Initiative

The week of May 10 was seasonally cold; all areas of Iowa fell behind long term average degree-day accumulations. Departures from normal were equivalent to 2.5 days of May growth in northwest Iowa to 3.5 days in southeast Iowa.

Map of accumulated degree days from May 1 through May 17, 2009.

But there is a silver lining! Iowa farmers have planted over 80 percent of corn acres and around one-third of soybean acres statewide, numbers that are not only near normal, but clearly lead the rest of the Corn Belt states.  

The cooler than normal weather has slowed corn development, but also has delayed the growth of black cutworm larvae. Later this week, an article will be posted here with projected scouting dates across Iowa.


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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