Insects cost Mississippi cotton growers nearly $70 million last year, says Angus Catchot, with tarnished plant bugs responsible for more than half that amount — almost $40 million.

A distant second was the bollworm/budworm complex, at $14 million, and spider mites third at almost $8 million.

Fewer cotton acres in recent years have been a factor, Catchot says, concentrating insects that would otherwise be diluted across much larger acreages.

“Cotton doesn’t produce a lot of insects that move into other crops,” the Mississippi State University associate Extension professor of entomology and plant pathology said at the annual Delta Ag Expo at Cleveland, Miss. “Rather, cotton serves as a sink for most insects that move out of other crops and from field borders, ditch banks, etc.”Controlling insects early, particularly plant bugs, can pay, Catchot says.

“We have consistently seen a net return from Diamond insecticide the third week of squaring or first week of bloom. We’re seeing a yield increase by doing this early rather than later. Preliminary research in the lab shows that when adults are exposed to Diamond, it reduces egg lay, and a lot of the eggs that are laid don’t hatch.”

For subsequent applications, when nymphs get embedded in cotton plants, tightening intervals to 4 to 5 days will provide better control than 7 days.