COLUMBUS, Ohio -- After the wind storm from Hurricane Ike, Ohio farmers are finding their corn in one of two states: either standing relatively well or taking a beating, and it pretty much depends on the stage of maturity as to how difficult the crop will be to harvest.
Wind damage appears most severe in drought-stressed corn that had died prematurely, resulting in weak stalks, and late-planted corn that had shallow, limited root systems.
"It's not uncommon to see considerable variability in stalk lodging within cornfields, with those areas of fields where corn ponding occurred in June followed by drought stress in July and August exhibiting the worst damage," said Peter Thomison, an Ohio State University Extension agronomist. "It's also remarkable how well corn is standing in many fields despite the high winds."
Thomison, who also holds an appointment with the Ohio Agricultural Research and Development Center, said that, while evidence of wind damage is widespread, severe damage, which may result in significant yield losses, seems more localized rather than statewide.
"Growers are likely to see three scenarios with wind-damaged corn: the tops blown off above the ear (there is minimal damage associated with this condition), breakage below the ear, and plants broken off at the base," said Thomison. "With the last two situations, harvesting the corn for grain will be difficult to near impossible if the grain is still very wet and corn is nearly flat on the ground."
Thomison said that harvest losses could range from a modest 1 percent to 5 percent per field, up to as high as 40 percent to 50 percent, depending on how badly the crop lodged and what the weather does over the next few weeks.
Rains could invite disease problems, said Pierce Paul, an OARDC plant pathologist.
"Anything that causes the ears to be in contact with the ground could potentially lead to ear mold problems," said Paul, who also holds an OSU Extension appointment. "Corn at the stage of development before black layer and lying on the ground is most vulnerable to infection because the husk is not fully mature."
Paul said that a number of growers were expressing concerns about the development of Aspergillus and the accumulation of aflatoxins, problems commonly associated with drought-stressed crops. Aspergillus can infect grain and produce aflatoxin under a wide range of conditions: temperature between 54 degrees and 108 degrees Fahrenheit; kernel moisture between 15 percent and 25 percent; and relative humidity above 80 percent.
"Downed corn will certainly be exposed to these conditions, especially high moisture if it rains, and since Aspergillus is a soil-borne fungus infection could easily occur," said Paul. But, he added, growers should also pay attention to such ear mold diseases as Fusarium and Diplodia, which could develop if damaged ears come in contact with moist soils. Any condition that increases moisture in the grain, puts maturing grain in contact with the soil, restricts drying, and makes harvest operation difficult could promote fungal growth and toxin contamination.
"What we don't want right now is rain. That will just aggravate the situation," said Paul. "If growers do face that situation, they should look for any discoloration or moldy growth on the ears they may scout for in their fields. They should have suspect grain analyzed for mycotoxins before feeding to livestock."
The most important thing right now is for growers to earmark those severely wind-damaged fields for priority harvest if grain moisture is appropriate.
"Growers need to prioritize fields that have severely lodged corn for early harvest," said Thomison. "They need to get those ears off the ground to limit further weathering losses."
Thomison said that dry conditions throughout July and August set the stage for lodged corn, and the high winds from Hurricane Ike exacerbated the situation.
"This is the worst lodging I've ever seen in corn across such a widespread area," said Thomison. "With the drought conditions we were just ripe for stalk quality problems, and now in terms of stalk lodging, it seems nearly everywhere."
Like corn, the state's soybean crop could be facing disease problems if rainy weather occurs before harvest. Phomopsis, driven by moist conditions, could set in damaged pods.
"The damage to the soybean crop, like corn, is localized. For some soybeans, the stems were broken and on the ground. Those are the plants that should be harvested as soon as possible to save the pods," said Anne Dorrance, an OARDC plant pathologist. "For other soybean plants, the pods were completely blown off the plant. In that situation, the plant is gone and there's nothing that can be done about that."
For more information on crop condition, harvest tips and equipment adjustment, refer to the OSU Extension Agronomic Crops Team Web site at http://agcrops.osu.edu. The team will include a report on the state of Ohio's field crops and how to handle damaged corn and soybeans in next week's issue of C.O.R.N. (Crop Observation and Recommendation Network).