Excessive moisture from heavy rainfall has set the stage for disease problems in Louisiana rice fields, LSU AgCenter experts told farmers attending a series of clinics in Evangeline Parish.
“With the rain we've been having, it's sure to come soon,” said Clayton Hollier, plant pathologist with the LSU AgCenter. Hollier said conditions will be prime for fungal diseases, principally sheath blight and blast, and he urged application of fungicides, if necessary, when rice heads start to emerge.
Delaying an application of chemicals to treat sheath blight by just five days can decrease yield by 500 pounds an acre, Hollier cautioned, so it's better to spray two days earlier than two day late.
Flooding from heavy rainfalls has introduced the sheath blight inoculum high up on the plants, Hollier said.
LSU AgCenter entomologist Boris Castro said rice water weevils are heavily concentrated in some areas this year, but are not as common in other fields. Chemicals to replace the weevil insecticide Icon, no longer being manufactured, are being tested at the LSU AgCenter's Rice Research Station, he said.
Castro urged farmers to scout for rice stink bugs, a close second to the weevils for damage to the state's rice crop. He said stink bugs are accumulating in grassy weeds next to rice fields, so managing weeds is a top priority.
Castro also said stink bugs can reduce yields up to 10 percent. In addition, milling quality losses from peckiness caused by stink bugs is more difficult to estimate but may represent a more significant profit loss for producers.
Castro warned that corn borers have been a problem for rice in central and north Louisiana in the past two years, especially for fields adjacent to corn crops.
Johnny Saichuk, LSU AgCenter rice specialist, said this year's growing season started with a warm March that encouraged farmers to plant early, followed by a cool April and then a wet May.
Saichuk is concerned rice plants have grown quickly, and tall plants at the green ring stage often don't have a high yield. The LSU AgCenter expert also said he's concerned rice plants subjected to excessive flooding have become tall and spindly, and spindly plants often don't have a high yield either.
Saichuk said he's inspected several fields of herbicide-resistant Clearfield 161 rice that don't look healthy, for reasons yet to be explained, after being sprayed with the Newpath herbicide.
LSU AgCenter weed scientist Eric Webster said cool nights in recent weeks slowed plant growth and may have interfered with the plants' ability to metabolize chemicals such as Newpath and Command.
Webster said he has been investigating herbicide drift problems. Herbicides are best applied with a slight breeze instead of calm conditions. With no wind stirring, he explained, cool air masses mix with warm air and can carry chemicals for several miles.
Although the flood water has receded, farmer Jeffery Sylvester of Whiteville, La., said he still is reeling from 20 inches of rain.
Sylvester and his two brothers, Chet and Teddy Sylvester, will have to replant 1,500 acres of 2,000 acres of rice that was submerged by flooding in northern Evangeline and St. Landry parishes.
In several of the Sylvester's fields, the dead rice plants were starting to decay on the day of the meetings.
Although rice is grown in flooded fields, water levels are controlled to avoid covering the plants.
Sylvester, president of the Evangeline Rice Growers Association, said planting had been staggered to allow harvesting one field at a time. Now everything will have to be harvested at once — and later than planned.
“We'll be harvesting in the heart of hurricane season now,” he said. “One hurricane at the wrong time could put us out of business.”
Sylvester recalled the last big flood was in June 1989, and it was too late to replant.
“And the bad thing about it was this was the year we thought we were going to make some money with the good prices,” Sylvester said.
USDA's weekly crop report for the week of May 24 showed 97 percent of the state's rice acreage had been planted, but the state's overall crop condition had declined.
Bruce Schultz is a writer for the LSU AgCenter. e-mail: [email protected]