Louisiana makes push to eradicate remaining boll weevils

The boll weevil can cause extensive damage to a cotton crop, but Louisiana’s boll weevil eradication program, which started in the late 1990s, has managed to rid most cotton fields of this insect.

“Is has been incredible,” said Ralph Bagwell, LSU AgCenter entomologist. “It’s unreal to know where we were one time and then see where we are today.”

Last year the total boll weevil catch in Louisiana was approximately one weevil per five acres.

“Ten years ago we had 100,000 weevils per acre,” Bagwell explained.

The program has been successful in the Red River Valley of northwestern and central Louisiana, but in the northeastern part of the state a few weevils remain.

LSU AgCenter cotton specialist Sandy Stewart said this growing season the state will take an aggressive approach in targeting those last boll weevils

“In those areas where we had one trap every acre or so, we’re going to move that down to one trap every 150 feet. Those traps will be monitored once a week instead of once every two weeks,” Stewart said.

The boll weevil eradication program has three components that have made it successful — treatments in the fall to keep the pest from overwintering, monitored traps and insecticide applications when needed during the growing season.

Both Bagwell and Stewart agree that the last weevils are the hardest and most expensive to eradicate.

“We have a few isolated areas where we continue to catch weevils, and some of this is due to the configurations of the field and the number of overwintering habitats in the fields,” said Stewart.

In addition, the experts say the accomplishments of the program sometimes seem to undermine its completion.

“The sign of the program’s success is that the weevil has become a non-entity for growers,” explained Bagwell. “Growers have become lackadaisical about the boll weevil and the eradication program.”

Growers can help by allowing space to drive around their fields and making traps accessible to those who are monitoring them.

“Farmers should try to not knock traps over, or if they knock them over to pick them up,” Bagwell said.

If left unchecked, boll weevil infestations can wipe out a cotton field, Bagwell warned, explaining that weevils feed on the fruiting parts of the plant and can cause significant yield losses.

The presence of the boll weevil also meant added expenses to growers. Before the program began eliminating infestations of weevils from cotton fields, growers were spending $15 to $20 an acre on boll weevil control.

Stewart says the aggressive approach to wrap up the eradication program will continue into the fall, since the boll weevil can survive the winter in dead plant material left in or around cotton fields.

“Once the weevil is eradicated, the program will move into containment or monitoring phase,” Stewart explained.

The boll weevil is unique — another factor that makes its eradication possible.

“It can be eradicated, because the only known host of the boll weevil on which it can reproduce in North America is cotton,” Stewart said.

Tobie Blanchard writes for the LSU AgCenter. 225–578–5649 or [email protected].

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