Civic Communications Specialist
2400 S. Scenic Ave.
Springfield, MO 65807
July 27, 2012
Field Scouting Report for July 18...
Aflatoxins and Spider Mites Pose Greatest Concern
this Week to Corn and Soybean Producers
LAMAR, Mo. - Fields six miles southeast of Lamar were scouted on Wednesday, July 18 by Wyatt Miller, an agronomy assistant with University of Missouri Extension in Barton County.
Corn scouted this week was between dough and dent stages. Because of the drought significant yield losses are expected in several fields. Some producers may consider using corn as forage for livestock.
"We encourage producers to get a quantitative lab test for nitrates with drought stressed corn. Those who will be harvesting corn should be aware of the potential for Aflatoxin in corn," said Miller.
Aflatoxins are generally caused by Aspergillus, which is typically associated with drought stress and evident as a greenish yellow to mustard-yellow mold growth on the ear.
Soybeans scouted this week were between stages v-6 to R-2, full flowering. Some grasshoppers were seen this week under threshold levels; treatment is justified when defoliation reaches 30 percent before bloom and 20 percent between bloom and pod fill.
"Drought conditions have reduced most insect populations, but have increased the chance for two-spotted spider mites. Some spider mites were found this week under threshold levels," said Miller.
Producers should scout for spider mites near the edge of fields on yellow speckled leaves near grassy boarders or gravel roads. When scouting, shake infested leaves over white paper and look for small yellow mites crawling.
Spider mites are very small, yellow-green to red, and best seen using 20X magnification. 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 after pod set.
Link for more information on Two spotted spider mite: http://ipm.missouri.edu/IPCM/2012/6/Spider-Mites-Problems-Emerging-in-Dry-Areas-of-State/
For more information on this scouting report or to learn how you can receive it by telephone each week, contact the MU Extension Center in Barton County at (417) 682-3579. These weekly field crop scouting reports are sponsored by MU Extension in Barton County.
PHOTOS AVAILABLE: Photos to accompany this and other field crop scouting reports can be found online at http://www.flickr.com/photos/muextension417/sets/72157626330510483/.
Source: Jay Chism, (417) 682-3579