Herbicide carryover a concern in fall-seeded crops
Fields east of Lamar in Barton County were scouted on Aug. 29 by Wyatt Miller, an agronomy assistant with University of Missouri Extension in Barton County.
Soybeans scouted were in the beginning seed stage. Soybean podworms were seen again near threshold levels.
"Soybean podworm treatment is justified when larvae exceed one per linear foot of row and 5 percent or more of pods are damaged," said Miller.
Producers should consider yield potential before insect treatment. Those considering using soybeans as a forage, should check herbicide and insecticide labels for harvest restrictions and can expect removal rates of about 10 pounds phosphate, 25 pounds potash, and 45 pounds of nitrogen per ton.
"Recent rains have given some producers hope for fall-seeded crops, however because of the drought there is an increase chance of herbicide carryover," said Miller.
Those who plan to plant winter wheat or fall-seeded forage grasses should consider factors that influence the likelihood of herbicide carryover. These include type of herbicide applied, rate of herbicide applied, time herbicide was applied, and most importantly amount of rainfall received since herbicide application.
A soil bioassay should be conducted on fields with high concern or uncertainty. A bioassay consists of collecting soil from several places in the field and planting seed in it to see how it grows.
Those seeding cereal grains with the main purpose of grain production should wait until later in the season before seeding to reduce the risk of and Hessian fly damage.