Friday, May 28, 2010

Corn Anthracnose Showing Up in Area Fields

By David Burton
University Extension

The corn fields east of Lamar were scouted by Jay Chism, an agronomy specialist with University of Missouri Extension, on May 24 and are showing signs of anthracnose, a fungal disease made worse by the region’s wet weather.

“The corn anthracnose is developing on the lower leaves of area corn fields. The disease overwinters on corn residue, so fields planted to corn following corn tend to show more infection,” said Chism.

The fungus is usually splashed up on lower leaves from spring rainfall, although some spores can also be carried by wind. Anthracnose lesions are usually oval to spindle shaped and may merge together to kill larger areas of leaf tissue.

“On many plants the lesions concentrate toward the leaf tip that gives the leaf a fired appearance that might be mistaken for nutrient deficiency or herbicide injury,” said Chism.

Generally, corn anthracnose will stop when weather conditions are drier and warmer. Under favorable conditions (warm, wet weather) anthracnose may move up the plant to the ear leaf.

“For the most part, anthracnose is not a serious problem and fungicides are not recommended this early in the season. If the disease moves up to new leaves, fungicides can be applied later in the season when other foliar diseases, such as gray leaf spot and southern rust may threaten this season’s crop,” said Chism.

It is important that producers continue to scout for insect damage in their own fields.

“I observed leaf feeding from adult corn root worm beetles or spotted cucumber beetles on a few fields this week, but no significant damage that justified control for now,” said Chism.

The MU Extension Center in Barton County has information about foliar fungicides, as well as pictures of viral diseases, anthracnose and recent insect damage posted online at http://extension.missouri.edu/barton.

For more information on this scouting report, or to learn how you can receive it a week earlier by telephone, contact the MU Extension Center in Barton County at (417) 682-3579.

Or you can hear the latest scouting report online at http://tinyurl.com/23swqol.

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