Degree Days Continue to Lag

July 1, 2008

By Rich Pope, Department of Plant Pathology

Another week of slightly cool days with scattered storms has Iowa farmers facing uneven stands in many fields. Cumulative heat during the week of June 23 lagged behind long term averages by 10 to 25 degree days in Iowa. The cool temperatures and still wet soils provide stresses to struggling crops, and those stresses are showing up in poor growth.  As we get more heat the corn and soybean should recover, but this early summer has predisposed the crops to future stresses.

That said, some fields that got planted by mid-May have escaped the onslaught of flooding and ponding and are doing quite well. 

The first 2008 report of soybean aphid in Iowa was by ISU field agronomist Brian Lang in Winnesheik County on Saturday, June 28. The infestation was reported as scattered clusters of small (5-30 aphids per soybean plant).

Rich Pope is an extension specialist with responsibilities in the Corn and Soybean Initiative.

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