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Degree Days - We Don't Need Stress!

By Rich Pope, Department of Plant Pathology

It is beyond time to get hot summer weather started! Both corn and soybean are (finally) in reproductive stages, and parts of Iowa are over 200 degree days behind normal. 

But we don't want to make up that deficit with significantly above-normal temperatures, as high August temperatures mean stress that can cut yield potential dramatically. In 1992, we were nearly as far behind as now, and the cool August weather then produced an above-normal yielding crop, however the grain was wet and fall grain handling and dry down were significant issues. 

We cannot say yet if there will be a repeat of 1992. The ideal weather recipe now is not too cold and not too warm, with a little rain mixed in. Anything cooler and we delay maturation, anything warmer and we cut yields.  

 Accumulated degree days from May 1 through August 2, 2009

Observations indicate soybean aphid numbers are increasing, most notably in northern and central Iowa. Scouting fields is critically important. Foliar corn diseases also warrant monitoring -  eyespot in norther parts of the state and gray leaf spot towards the south.

There is an interesting graphic and story of the July 24, 2009 hail storm that struck northeast Iowa on the Iowa Environmental Mesonet (IEM) website. The IEM contains a weatlth of weather and climate related information for Iowans.

 

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

 


This article was published originally on 8/4/2009 The information contained within the article may or may not be up to date depending on when you are accessing the information.


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