Fields north of Liberal saw both crops and insects affected by drought conditions.
Wyatt Miller, an agronomy assistant with University of Missouri Extension in Barton County, scouted acres where corn was between stages R-1 and R-2. R-1 is the silking stage and R-2 is the blister stage.
"Currently, weather conditions are hot and dry." Miller said. "The majority of Missouri is in a drought. With temperatures expected in the upper 90's and no chance of rain over the next few days, it is likely crops will be stressed with the potential for yield loss to follow."
Spider mites. From Farm Progress Aug. 2010
Common rust has increased from last week but disease pressure is greatly reduced in hot dry weather and should not be much of a concern in dry land corn. Miller says those who irrigate should keep an eye out for disease pressure.
Soybeans scouted this week were between stages v-3 to v-8. No diseases were found on soybeans this week, and little defoliation was seen. Treatment is justified when defoliation reaches 30 percent before bloom and 20 percent between bloom and pod fill.
"With drought conditions most insect populations have declined. However, drought conditions greatly increase the chance for two-spotted spider mites. Producers should scout for spider mites in yellow areas of the field," said Miller.
Spider mites, adult and larvae. University of Missouri
Generally, spider mites will first be found near the edge of fields with grassy boarders or near gravel roads. When scouting, Miller suggests hold a white sheet of paper below the upper trifoliate and tap the leaves onto the paper. Spider mites will be very small, but often times tiny, yellow-green to red specs can be seen crawling on the paper.
Treatment is justified when foliage yellowing reaches 20 percent and mites are present on plant before pod set, or when foliage yellowing reaches 10 percent and mites are present on plant after pod set.
Source: University of Missouri Extension