COLUMBUS, Ohio — Low grain prices, unfavorable weather and hurricane-related transportation issues have some Ohio growers dragging their feet with corn harvest. But any further delay could cause severe stalk lodging and subsequent yield losses.
Peter Thomison, an Ohio State University Extension agronomist with the Department of Horticulture and Crop Science, said that farmers should harvest corn as soon as field conditions are suitable to allow entry of equipment, and target those fields at greatest risk from stalk lodging first.
"Early season conditions — a wet, cool spring, followed by a hot, dry summer — have set the stage for some of the worst stalk quality problems we've seen in several years. So we are really encouraging people to get their crop out of the field as soon as possible," said Thomison.
According to the Ohio Agricultural Statistics Service, about 42 percent of the state's corn has been harvested. The longer growers wait to harvest, the more severe the problem will become.
Stalk lodging is the breakage of the stalk below the ear, caused by severe late-season weather, European corn borer infestations or stalk rot, or a combination of any of those factors. Stalk lodging can slow harvest and cause significant yield losses.
Recent Ohio State University Extension research on delayed harvesting has shown that the majority of stalk lodging occurs between early- to mid-November and early- to mid-December.
"What we see is most stalk rot occurring in corn during the early stages of harvest delay. After that, you start seeing stalk lodging. In hybrids with poor stalk quality as much as 20 percent to 30 percent of the crop can lodge in early November and after that you can see it skyrocket to 70 percent, 80 percent, even 100 percent," said Thomison. "Growers have to be aware of the fact that there is no benefit to leaving their corn in the field after early November. It's not going to dry down appreciably after that."
In addition to yield losses, the longer corn is left in the field, the greater the chances for mold and ear rot development, which can lead to mycotoxin problems. Mycotoxins, such as aflatoxin, can cause animal and human health problems.
Ohio growers, however, should not be overly concerned about aflatoxin contamination, said Pierce Paul, an Ohio State plant pathologist with the Ohio Agricultural Research and Development Center.
"The infection of the ear with Aspergillus, a fungus that causes aflatoxin, does not necessarily mean that aflatoxin is being produced," said Paul. "Aflatoxin is only produced under certain environmental conditions, like drought and high temperatures. While drought conditions did occur in some parts of the state this season, the weather conditions have just not been favorable enough to produce a major aflatoxin problem this year."
However, Paul emphasized that care needs to be taken to prevent accumulation of mold growth and toxins in stored grain. For information on aflatoxin visit OARDC's Department of Plant Pathology "Ohio Field Crop Diseases" Web site at http://www.oardc.ohio-state.edu/ohiofieldcropdisease/Mycotoxins/mycopageaflatoxin.htm.
To minimize the chances of mold growth, growers should earmark lodged cornfields first for harvesting.