By Rich Pope, Department of Plant Pathology
It is September 24 and thankfully no frost to speak of yet. The 2008 season will be one to look back on as a reference for variable weather effects on crops.
I last posted degree day data in mid-August. As mentioned in that article, daily degree day accumulations are less critical once corn and soybean progress to reproductive stages, when general water and temperature stresses and solar radiation drive development.
In the last month, we have continued the season-long pattern of lagging in degree day accumulations behind long-term averages. But last month's lag has actually been good, especially with corn, in that the plants have stayed healthier longer. Many parts of the state needed lower stress conditions to make up for the tumult of the early growing season, and it appears that for the most part we got what the doctor ordered.
Average date of first killing frost (28°F or below) in Iowa ranges from the first week of October in northwest Iowa to around October 20--25th in southeast Iowa. Every day we make it until and past those times will be increasingly good news!
Rich Pope is an Extension specialist working in the Corn and Soybean Initiative