LSU AgCenter plant pathologist Boyd Padgett talks about the absence of Asian soybean rust in this year’s crop during the LSU AgCenter field day July 20 at the Northeast Research Station in St. Joseph. (Photo by Mary Ann Van Osdell. Click on photo for downloadable image.)

News Release Distributed 07/21/10

ST. JOSEPH, La. – Growers learned the importance of identifying pests, diseases and weeds in crops at the 81st annual LSU AgCenter Northeast Research Station field day July 20.

The program highlighted research on soybeans, cotton, rice and corn at the station.

Ron Levy, LSU AgCenter soybean specialist, said more than one million acres of soybeans have been planted this year and that rains have made the difference between a mediocre and excellent crop.

“There is a big demand for U.S. soybeans,” Levy said. “I think we’ll see a continued increase in acreage.”

Asian soybean rust has not yet been found in Louisiana, said Boyd Padgett, LSU AgCenter plant pathologist. “It is probably not going to be an issue this year.”

Although rust is absent, “We’re finding Cercospera moving in rapidly,” Levy said. “The good news is it is coming in late, so yield damage will be minimal.”

Red-banded stink bug numbers have been low in soybeans, said LSU AgCenter research associate Josh Temple. “But we are starting to see a complex of brown stink bugs.” He said soybeans should be sampled using a sweep net or shake sheet as soon as the plants begin to flower.

Jim Griffin, LSU AgCenter weed scientist, explained the eight categories of soybean reproductive growth. “This is important for fungicide applications and to know the application of desiccants,” he said.

Rogers Leonard, LSU AgCenter entomologist, said the tarnished plant bug is the key pest in cotton. “We are trying to understand how to control it,” he explained. “Tools that we currently have are not very effective against this pest.”

LSU AgCenter entomologists have seen a significant increase in the fall armyworm in cotton. “Fall armyworm is a man-made problem,” Leonard said. “Get rid of your weeds, and you won’t have fall armyworm.”

“The reniform nematode is a real problem pest for us in Louisiana,” added Charles Overstreet, LSU AgCenter nematologist. Reniform nematodes occur in 50 percent of cotton acreage in Louisiana, and root-knot nematodes are in 25 percent, he said. He is researching seed treatment nematicides and the use of a fumigant later.

Natalie Hummel, LSU AgCenter entomologist, said she is conducting a field study of rice water weevils to review the insecticides used in farmers’ fields. The most northern site is in Tensas Parish. She encouraged the 171 attendees to follow her blog on rice insects at louisianariceinsects.wordpress.com.

Addressing corn, Bill Williams, LSU AgCenter weed scientist, said the No. 1 problem is preplant weed control.

“The big problem we’re dealing with is ryegrass resistance to glyphosate,” Williams said. “Unfortunately, we don’t have many good answers to it right now.”

Williams said henbit has been a problem the last five to six years and another problem this year is mare’s tail. “In about half the fields we look at, one of those three is going to be a problem.”

Mary Ann Van Osdell