September 22, 2004 | By: Laura Skillman
PRINCETON, Ky.

Corn producers should scout fields for potential lodging problems because of weakened or damaged stalks.

Because the problem results in the stalks falling over, making harvest more difficult, farmers are encouraged to check their fields and consider harvesting any fields that show signs of lodging first, said Paul Vincelli, Extension plant pathologist in the University of Kentucky College of Agriculture.

An earlier harvest may mean corn will have to be dried adding to the cost of production, but lodging can result in a difficult harvest with some of the corn left behind in the field. Losses from lodging can range anywhere from 5 bushels per acres to 10 times that amount.

Stalk rots are a major player in lodging along with insect damage and plant physiology. Weather conditions were favorable for a number of leaf diseases this year such as gray leaf spot. A number of fields in western Kentucky also were damaged by northern leaf blight, an unusual occurrence in Kentucky because temperatures generally are too hot for the disease. This year however, temperatures and wet conditions in July and August resulted in some pretty striking epidemics in some fields, Vincelli said.

Some higher yielding fields where normally 200 plus bushels per acre is achieved, yield reductions were in the 50-bushel per acre range, he said.

These leaf diseases allow the plant to dry down more quickly resulting in the plant pulling nutrients from the stalk to complete grain fill in the ears, making the stalk more susceptible to rots.

“I think it is always a good idea to scout for stalk strength to see which fields have potential lodging issues,” Vincelli said.

Insects also are related to stalk lodging, breakage and ear drop, said Ric Bessin, UK Extension entomologist. In the western part of the state it is Southwestern corn borer and European corn borer. In other areas, European corn borer can pose a problem.

They contribute to this problem in two ways, first, by tunneling into the stalk and ear shank, mechanically weakening the plant. Secondly, they injure the plant and create entry wounds that pathogens can use to colonize the plant. So the corn borers will contribute to increase stalk and ear rots, he said.

Bt corn, by reducing the corn borer injury, also will reduce the incidence of some type of stalk and ear rots as these plants have few wounds suitable for pathogen colonization.

This year’s planting conditions allowed much of the crop to be planted early and harvested early reducing the likelihood of borer damage, Bessin said. However, there were some fields that had to be replanted due to water and some late planted fields, as well. Most growers are aware of the corn borer issues and use Bt corn for late plantings, unless their market doesn’t allow for its use. Those fields should be identified for early harvest.

“As soon as they can harvest that corn, they really need to even though it will cost money for drying, it’s better than having it on the ground,” he said.

To determine lodging potential, walk through the field holding your arm at chest level and push the plants 8 to 10 inches, to see if they bounce back or not. If 10 to 15 percent of the plants show signs of possible lodging below the ear, farmers may want to consider harvesting those fields first to reduce the potential of downed corn.

Contact: 

Writer: Laura Skillman 270-365-7541ext. 278
Sources: Paul Vincelli 859-257-7455 ext 80722
Ric Bessin 859 257-7456