Time To Monitor Wheat Fields For Aphid Populations
Recent surveys of wheat fields in Barton County, MO, turned up threshold levels of bird cherry-oak aphids due to the mild winter.
March 9, 2012
Wheat producers should be scouting their fields for aphids that can pull juices from the plants and transmit the virus called Barley Yellow Dwarf.
Recent surveys of wheat fields were conducted in Barton County by Tim Schnakenberg, regional agronomy specialist based in Galena and Wyatt Miller, an agronomy assistant based in Lamar.
"In most fields surveyed, threshold levels of bird cherry-oat aphids were observed," said Schnakenberg. "The outbreak is attributed to mild winter growing conditions that have favored their early development in wheat fields."
Bird cherry oat aphid is a small aphid with an olive-colored body and reddish-orange patches on its back. Antennae, eyes and tips of legs and cornicles are black in color.
Greenbug should also be monitored. Greenbugs are small pear-shaped aphids, 1/16 inch in length and are pale yellow to pale green in color. It has a predominant dark green line running down the length of its back.
The economic threshold population in a field that justifies an insecticide application is 12-25 bird cherry oat aphids per foot of row. Greenbug thresholds are 50-100 greenbugs per foot of row on wheat up to six inches tall. Once the wheat is over six inches the threshold would be 300 or more according to Schnakenberg.