WOOSTER, Ohio — Early planted corn throughout Ohio is beginning to germinate and, in some cases, is already emerging above-ground, signaling that the crop may have escaped serious disease problems potentially brought about by cold, wet conditions soon after planting.
However, the plants aren't out of the woods yet.
"After checking some fields, the seeds look like they are in pretty good condition. They are starting to germinate, with roots of plants in some areas an inch to an inch and a half long," said Pat Lipps, an Ohio State University plant pathologist with the Ohio Agricultural Research and Development Center. "If we get warmer, dry weather, I think the prognosis of having few problems with seedling blight is pretty good. However, if the weather takes a turn to wet again, even if it warms up, I can see some pretty severe seedling blight diseases developing."
Growers are concerned about the development of seedling blight diseases — Pythium, for example — which thrive under saturated soil conditions and can easily kill young seedlings that are slow to germinate in cool conditions.
"We have to remember that corn is a tropical plant. It likes warm weather and grows quicker in warm weather," said Lipps. "When you have saturated conditions and the temperatures are cold, the seed may germinate, but the roots don't grow very much. This leaves an opportunity for fungi to develop and kill the seedlings. What we are hoping for is warm weather. This will give the plants a better chance of surviving."
Pythium is a water mold. It produces swimming spores attracted to the sugars "leaked" by seeds and roots. The spores infect the plant by colonizing the cells of roots and seedling crowns. When the crown of the seedling is colonized, the plant dies. Other seedling blight diseases, such as Fusarium and Rhizoctonia, function in a similar manner.
In southern Ohio, corn is emerging. Throughout northern Ohio, seedlings are just beginning to germinate and will likely emerge after only a few days of warmer weather.