European corn borers have been found in a northeast Louisiana field — marking the first confirmation of this insect's presence in the state for the past 41 years.
LSU AgCenter experts say the pest's appearance is significant but not a cause for immediate alarm. Further research is needed to determine how to combat it and prevent it from becoming a major problem, according to Boris Castro, an LSU AgCenter entomologist.
The finding of the pest in a corn field in Morehouse Parish was confirmed June 11 from samples collected, Castro said, adding that the pest appears to be confined along the northern border of the state.
“Finding this insect in Louisiana is important from the standpoint that we need to conduct additional research and refine the strategies we use to manage insects,” Castro said. “But we don't need to be too concerned about finding this borer right now, because we are already managing two important corn borers — the sugarcane borer and the southwestern corn borer.
“However, it is a good idea for producers to keep a watch on their fields to see whether additional borers are spotted,” Castro said, adding that Louisiana is the only state with confirmation of three borers that affect corn.
The European corn borer not only attacks corn, it also can infect other crops such as cotton, beans, peppers, potatoes and several other vegetable crops, Castro said. The behavior of the European corn borer is similar to the sugarcane borer and the southwestern corn borer, and it can be managed in much the same way as those pests, he said.
“Setting out pheromone traps for the European corn borer is the next step we in LSU AgCenter will conduct,” Castro said. “There are two ecotypes of the European corn borer, and we must determine which one we have and how many so that we will know how to manage it better.”
An ecotype is a strain of the same species that has a preference for different crops or environmental conditions, Castro said.
Officials say the LSU AgCenter also will develop educational information that will explain how to identify and manage these pests. As for control measures, Castro said using a residual pesticide would be advantageous, since residual pesticides are effective for several days after being applied.
“The adult pests lay eggs over several days,” he said. “To effectively fight the European corn borer, it is better to use a residual product that can kill the larvae over several days before they get in the stalk.”
Killing the larvae before they enter the stalk is an important control measure, because once the pest is inside the plant, it cannot be reached by an insecticide and is less likely to be killed by natural enemies, Castro said.
“The eggs take three days to four days to hatch,” he said. “The larva then eat on the leaf tissue and leaf sheath of the plant for about a week before boring into the stalk.”
Bt corn and Bt cotton are very effective in controlling these three borer species, Castro said.
The European corn borer has been present in all corn-producing states, including Arkansas and Mississippi, but had not been documented in Louisiana since 1962, Castro said.
But he said this recent appearance of the European corn borer in Louisiana comes as no surprise. “We have movement of these insects (borers) all the time,” he said. “The most important thing for farmers to do now is scout their fields regularly and take the appropriate action if they do find any of these three borers. They can all be managed in a similar way using the same products.”
In non-Bt corn, the European corn borer can be controlled with the same insecticides recommended for southwestern corn borer and sugarcane borer, according to LSU AgCenter entomologist Jack Baldwin.
“Producers should also continue to use the same economic threshold of 5 percent infested plants when making decisions about insecticide applications,” Baldwin said.
For more information on how to identify and manage pests in corn, go to www.lsuagcenter.com/Communications/pdfs_bak/pub2284managinginsects.pdf.