Posted 16 May 2010. PMN Crop News.
Check for Brown Wheat Mites in Winter Wheat
Source: Oklahoma State University Press Release. www.dasnr.okstate.edu
Stillwater, Oklahoma (April 29, 2010)--Wheat growers in western Oklahoma and other areas of the state largely unaffected by recent rains should be on the lookout for brown wheat mite infestations.
“Producers need to remain alert to these problems so that their wheat is not suffering dual problems of dry growing conditions plus the presence of brown wheat mite,” said Tom Royer, Oklahoma State University Cooperative Extension integrated pest management coordinator.
The mite is small – about the size of a period in this story – with a metallic brown to black body and four pair of yellowish legs. The forelegs are distinctly longer than the other three pair. It feeds by piercing plant cells in the leaf, which results in stippling. As injury continues, the plants become yellow, then dry out and die.
“Numbers will decline if a hard, driving rain occurs, with spring populations typically – but not always – beginning to decline in mid- to late-April,” Royer said.
The best time of the day to scout for the pests is mid-afternoon. They do not produce webbing and will quickly drop to the soil when disturbed.
Research suggests that a treatment threshold of 25 to 50 brown wheat mites per leaf in wheat that is 6 inches to 9 inches tall is economically warranted. An alternative estimate is several hundred per foot of row.
“Just make sure to check your field before deciding to spray as rain may have already helped kill off some of the pesky pests,” Royer said.
Check OSU Current Report CR-7194, “Management of Insect and Mite Pests in Small Grains,” at osufacts.okstate.edu for registered insecticides, application rates and grazing/harvesting waiting periods.