Thrips numbers on cotton seem to have peaked in Virginia, but peanuts are taking a big hit and in some cases insecticide treatments don’t seem to be keeping pace with the ever-increasing numbers being found in test plots at Virginia Tech’s Tidewater Agricultural Research and Extension Center in Suffolk.

Virginia Tech Entomologist Ames Herbert says, it’s hard to compare thrips numbers researchers are seeing in peanuts versus cotton because of the differing amounts of plant material sampled in the two crops.

Herbert says only unopened terminal leaflets are sampled in peanuts, and that’s where thrips concentrate feeding.

“In untreated peanut plots, counts have gone from zero per 10 leaflet samples on May 17, to seven on May 24, to 18 on May 30. The result is not pretty, with damage ratings reaching 5-6 on a 0-10 scale,” the veteran entomologist and IPM leader says.

He points out that insecticide treatments, in general, are not keeping up with thrips pressure. A few are holding plants below a 2-3 injury rating. “If we can stay at the 2-3 level, I think peanut plants can achieve maximum potential,” Herbert concludes.

Results of Herbert’s thrips tests on peanut and cotton, plus other valuable production information will be discussed at a June 5 field day and crops tour at the Tidewater Station. Registration for the meeting begins at 8:30 and field tours start at 9 a.m.

rroberson@farmpress.com