Plant bugs have transplanted budworms and bollworms as one of the worst pests in Louisiana cotton.
“We deal with four primary plant bugs in U.S. cotton: the western tarnished, the flea hopper (a problem in Texas), the clouded plant bug (a problem in north Arkansas and Tennessee) and the tarnished plant bug,” says Ralph Bagwell, Louisiana State University AgCenter entomologist.
Over the last decade, says Bagwell, there have been “very significant changes” in tarnished plant bugs.
“It's changed incredibly since 1995. In the past, we were primarily dealing with weevils, bollworms and budworms. Sure, we treated for tarnished plant bugs, but we spent the bulk of our treatment money on the others,” he says.
With the elimination of weevils through eradication efforts and the arrival of Bt cotton, the significance of plant bugs has increased. There has also been a big increase in cotton damaged by the pest.
Ten years ago plant bugs were primarily pre-bloom pests, damaging small squares. “In retrospect, the insecticides we were putting out for weevils and worms were giving us coincidental control of plant bugs. Once those treatments were eliminated, plant bugs moved in and fed in different plant areas and at different times,” says Bagwell.
Now plant bugs are a “true villain. Today, I see more injury from this insect after first bloom than before. This pest can feed on just about anything — if it's a broadleaf, it's a meal,” he adds.
Properly managing today's plant bugs includes developing new guidelines for sampling procedures, thresholds and new control practices. Current sampling procedures are based primarily on scouting for plant bugs as a pre-bloom pest, not as a post-first bloom problem.
Once new sampling procedures are in place, treatment thresholds will be considered.