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July 8, 2003

Flooding could turn Indiana cropfields into watery graves

WEST LAFAYETTE, Ind. – Rain makes grain, according to an old farm adage. But too much rain, like parts of central and northern Indiana experienced within the last week, might damage the grain-making ability of corn and soybean plants, said Purdue University Extension specialists.

Flooded corn field
Download photo - caption below

"A whole range of problems is possible," said Bob Nielsen, Purdue Extension corn specialist. "There's no easy way to predict what can happen. Depending on how long the water sits on plants, there's likely to be outright plant death in some fields. At a minimum, I would expect a lot of root death."

Thousands of acres are submerged following torrential storms that dumped as much as 10 inches of rain in areas between Indianapolis and Elkhart. Severe flooding has turned many cropfields into temporary lakes.

More rain is possible this week in already drenched Indiana counties, according to the National Weather Service.

The same counties that received the weekend deluge were abnormally dry and needed the precipitation, said Rollin Machtmes, Purdue Extension educator in Howard County. What Howard County didn't need, however, was all the rain at one time, he said.

"Some farmers in my county are telling me they received 10 inches of rain," Machtmes said. "We needed the rain, but not that fast."

Machtmes said he's seen corn in waterways lying over that had started to tassel, as well as soybean fields with plants under water. A farmer with melon and tomato crops was pumping water off his fields, he said.

"The big question right now is, how many acres of corn were ready to tassel and what effect will that have on pollination?" Machtmes said.

Standing water invites any number of soilborne crop diseases, even after floodwaters abate, said Nielsen and Greg Shaner, a Purdue Extension plant pathologist.

"These conditions could predispose corn to stresses later in the season, especially if it turns drier later in the crop season," Nielsen said. "You can wind up with bacterial and fungal diseases on these saturated plants, as well as stalk rots. We'll have to wait and see."

Shaner said, "One disease in particular that could be a problem is Phytophthora root rot in soybeans. That can infect a plant at any time. If a root system has a lot of rot within it, the crop can go down pretty quickly.

"Sudden death syndrome is another concern. It may be a little bit early for the disease right now, but it is possible with the rain we're getting that it could be enough to trigger the disease."

SDS thrives in wet field conditions and can decimate a soybean crop. The disease causes small yellow blotches to appear on soybean leaves. The blotches grow larger in size and number, and the tissue within the infected area becomes brown and dies. Eventually all the leaves turn brown, limiting a soybean plant's ability to produce grain.

Some Indiana farmers with flood-damaged crops can recover part of their loss through crop insurance, said George Patrick, a Purdue Extension agricultural economist.

"About 60 percent of the acreage in Indiana is covered by crop insurance," Patrick said.

How much a farmer receives from an insurance carrier depends on how the farmer's coverage is structured, and whether it excludes high-risk areas.

"It depends on what the flooding is, relative to their crop insurance unit," Patrick said. "For some farmers it may be all the land they own or cash rent. In other cases it may be smaller optional units. All of those things were decided when the crop insurance was purchased. Farmers should report losses to their crop insurance agent."

For some farmers, the rain itself is an insurance policy against drought.

"We've seen a lot of stressed corn needing the rain," said Michael Reetz, Extension educator in Pulaski and Starke counties. "The soybeans hadn't grown a lot, either. They were maybe 2-3 inches above the ground."

For additional information on flooding, log onto the Extension Disaster Education Network Web site or call Purdue's toll-free Extension hotline at (888) 398-4636.

Writer: Steve Leer, (765) 494-8415,

Sources: Bob Nielsen, (765) 494-4802,

Greg Shaner, (765) 494-4651,

George Patrick, (765) 494-4241,

Rollin Machtmes, (765) 456-2313,

Michael Reetz, (574) 946-3412,

Ag Communications: (765) 494-2722; Beth Forbes,;


Related Web site:
Federal Emergency Management Agency flood page


Row after row of corn plants disappear into the rising waters of the Wabash River southwest of West Lafayette on Monday. With more rain forecast for today (Tuesday, 7/8), the river may not have crested yet. (Purdue Agricultural Communications photo/Tom Campbell)

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