Tuesday, November 18, 1997

Incredible number of weevils in some High Plains spots

By J.T. SMITH / Farm Editor

The boll weevil is finding ample lodging on the Texas High Plains.

More than 5,000 boll weevils literally swarmed around a single pheromone trap at the Texas A&M Agricultural Experiment Station in Lubbock on a recent calm and sunny day.

"I've never seen anything like this before," said veteran Texas A&M Entomologist Dr. Don Rummel. Rummel is nationally respected as a research entomologist who has studied the life of the boll weevil for 34 years.

The phermone trap - like hundreds of green traps you commonly see on fence posts and the like - is an "excellent survey sampling tool" of the boll weevil population, Rummel said.

A Grandlure patch used in the traps contains a synthetic duplicate of the sex pheromone produced by the male boll weevil as a communication device that attracts both sexes of the insect.

Rummel said the boll weevil swarm at the Experiment Station's trap was clear evidence that "there was indeed a large boll weevil population in parts of the High Plains this year."

Weevil no longer appears suppressed

Scarcity of overwintering habitat and suppression of the weevil through control programs prevented any significant populations of the insect on the High Plains for many yers.

Now, it appears weevil numbers are soaring rapidly up there.

Kerry Siders, integrated pest management agent for Hockley and Cochran counties, reported that High Plains researchers and weevil experts expect a three-fold increase in the population just this season.

Their predictions are based on the large number of healthy weevils emerging for diapause (hibernation) after a late, bountiful cotton crop provided plenty of food to fatten up for winter.

Plenty of fat should help them survive the winter.

The insects have anti-freeze too

But didn't some of the cold weather of late in the Lubbock area zap some evil weevils?

It was once thought that High Plains winters were "too cold" for the insect to survive in the region, said Dr. James Leser, professor and Extension Service cotton entomologist.

But even out in the open, boll weevils can take cold pretty well unless it is a real Siberian Express. And once they get under some winter protection like grass cover, it is like a blanket.

"Boll weevils have anti-freeze like fluids in their bodies that allow them to survive temperatures down in the high 20s," Leser said.

Those fluids, Leser noted, enable the boll weevil to overwinter in habitats such as grasslands in the USDA Conservation Reserve Program and then emerge again in the spring as a new cotton-growing season begins.

When weevils have nothing to eat in the spring, while waiting for one-third grown cotton squares to munch upon (and lay their eggs inside), they die of what's called "suicidal emergence."

The majority of the cotton was planted late, so there was some suicidal emergence by weevils the past spring - but nevertheless, the big populations that eventually developed on the High Plains surprised even the experts.

Rummel said all the scientists are "amazed" at the rapid spread of the pest since 1993. It was much faster than they had anticipated.

The boll weevil cost the High Plains alone $42.7 million in economic last year.

With harvest still in progress this year, the 1997 losses to the pest have yet to be figured.