Pest returns after 41-year absence

“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,” said Boris Castro, LSU AgCenter entomologist. “But we do need to conduct additional research and refine the strategies we use to manage insects.”

The pest was found in a corn field in Morehouse Parish on June 11and appears to be confined along the northern border of the state, according to Castro.

Castro advised producers to watch their fields for additional borers. The European corn borer not only attacks corn, it also can infest other crops such as cotton, beans, peppers, potatoes and several other vegetable crops.

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,” 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.”

The LSU AgCenter plans to develop educational information on identifying and managing the pests. Castro said using a residual pesticide for control would be advantageous.

“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 Louisiana’s 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.

The recent appearance of the European corn borer in Louisiana comes as no surprise, according to the entomologist. “We have movement of these insects (borers) all the time,” Castro noted. “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.

“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

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