Mississippi shifts mite recommendations

After 2 seasons of battling spider mites in cotton, Mississippi has changed its treatment recommendations in a way that will likely prompt earlier treatments.

As Angus Catchot, Extension Entomomogist explains it, the treatment trigger had been when 50% of the plants had spider mites 5 nodes down from the terminal and mite populations were increasing.

"It (the recommendation) now states that when 40-50% of the plants have spider mites and conditions are favorable for increase," Catchot says.

That may seem like a subtle difference, but the new recommendation looks at the entire plant, not a specific area. And the new approach only specifies that "conditions are favorable for increase."

This is a more preemptive strategy and somewhat tracks along with treatment triggers followed in California where spider mites are a regular problem.

At this week's Mississippi Agricultural Consultants Association meeting in Starkville, Catchot gave a presentation on spider mites. He showed maps that plotted initial pockets in 2006, mainly in the western side of the Delta, then followed with maps that plotted the wider spread of the pest as the season progressed.

"Mites have been considered a late-season pest," Catchot noted. "But over the last 2 seasons, we've seen them develop in early cotton, and that's the situation that really scares me."

He stressed the idea of picking materials that proved most effective in early season conditions if that's when treatments are needed. Some of the older mite control materials have not performed as well in early periods. Catchot theorized that mite egg laying was extremely active, and some of the established compounds did not have residual activity in those situations. Later in the season, these compounds actually worked better. By then, the populations probably were more heavily weighted toward adults, he said, and the older chemistry worked adequately.