Burning down the green bridge that gives insect pests a path to move from winter hosts to cotton plants may reduce in-season insecticide sprayings significantly and could protect seedling cotton from early damage, says an Arkansas State University Extension entomologist.

Scott Stewart told a group of cotton consultants during the recent Beltwide Cotton Conferences in New Orleans that timing pre-plant burndown weed control is critical to minimize early season insect problems.

“Controlling weeds in areas around the field and along ditch banks is also critical,” he said during the annual Cotton Consultant’s Conference segment of the Beltwide. “Such pests as the tarnished plant bug have a huge host range,” Stewart said. “Hosts include henbit and just about every cotton field has henbit. Spider mites also like henbit and that weed can be a part of the green bridge.”

Stewart said the green bridge is vegetation that harbors insect pests that move into cotton.

“We’ve seen a lot of changes in cotton insect control over the past few years,” he said. “Bt cotton, the boll weevil eradication program and crop rotation have changed the way we manage pests.” He said rotation to other crops, such as corn, may provide alternative hosts for sucking bugs and other insect pests.

No-till and reduced-till systems also affect pest survival. “A lot of areas have to use reduced-till to improve conservation, improve production and boost the bottom line, but farmers need to be aware of the effect on insects.”

He said some pests thrive in reduced-till systems. Cutworms, slugs, false chinch bugs and aphids, among others, may find favorable conditions in reduced-till fields. “A good burndown herbicide helps remove the green bridge that allows cutworms to move from one host to another,” he said.

email: rsmith@farmpress.com