The Mexican rice borer continues its eastward migration from Texas, with monitoring traps detecting adults near Lake Charles, La., according to LSU AgCenter entomologists.

“It’s just a continuing movement of what seems to be a rate of about 15 miles per year, and that’s what we predicted several years ago,” said LSU AgCenter sugarcane entomologist Gene Reagan.

The latest adult Mexican rice borer moths were found in traps monitored and maintained by the Louisiana Department of Agriculture and Forestry entomologist Tad Hardy. He said the monitoring has been possible because of cooperation between LDAF and the LSU AgCenter. “We’ve developed a very good relationship.”

Chris Carlton at the LSU Arthropod Museum identified the specimens as Mexican rice borers, Reagan said. The insect was first found in Louisiana in December 2008 in two LDAF monitoring traps, both north of Vinton, La. Next it was detected between Vinton, La., and Sulphur, La.

“More recently, the numbers of moths found in traps in that area have increased,” Reagan said. On May 16 and in several prior weeks, moths were trapped southeast of Lake Charles 15 miles from the nearest sugarcane fields and in another location northwest of Lake Charles adjacent to rice fields in production.

The detection of Mexican rice borers next to rice indicates the insect could be found in rice fields this year, Reagan said. But he doubts they will cause any significant economic damage during the first year.

Monitoring the insect’s movement from its origination in the Rio Grande Valley of Texas has been ongoing for several years, and continuing research has been done on controlling it in anticipation of its migration into Louisiana.

“We’ve done a lot to get ready for this,” Reagan said. “There’s no immediate reason for any alarm.”

Several new chemicals are effective at controlling the pest in sugarcane, and pyrethroid pesticides are labeled for the insect in rice fields, according to LSU AgCenter entomologist Natalie Hummel.

“You have to apply the treatments when the insects are on the outside of the plants,” Hummel said. In rice, seed treatments have activity against borers.

Timing is essential for sugarcane, she said, because more than half of the larvae that hatch on sugarcane will infest the plant within a day.

The Mexican rice borer is a stress opportunist, taking advantage of sugarcane plants that are drought stricken or diseased, Reagan said. He said he plans to burn sugarcane research plots near Beaumont, Texas, to see if that will control the insect larvae when they are small and inside the leaf sheaths before they bore into the midrib of the plant.

Reagan said he expects state and federal agricultural agencies to meet soon to develop a long-term management strategy.

A Mexican rice borer identification card can be found online by going to www.lsuagcenter.com and putting “pub3098” in the search box.

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