Civic Communications Specialist
2400 S. Scenic Ave.
Springfield, MO 65807
June 22, 2012
Field Scouting Report for June 13...
Japanese Beetle Counts High in Corn and Soybeans
LAMAR, Mo.On June 13, Wyatt Miller, an agronomy assistant with University of Missouri Extension, scouted fields in southeast Barton County.
Miller said corn scouted this week was between stages v-12 and R-1, silk emergence. Silk emergence is the stage when stress is most yield limiting (especially in drought).
Japanese beetle trap counts were high and treatment in corn is justified when three or more beetles are present on green silks, or when silks are eaten to one-half in or less, when pollination is less than 50 percent complete. Japanese beetles tend to stay on the edge of fields and often do not require treatment. Producers should still keep an eye on common rust.
Soybeans scouted this week were between stages V-4 to V-12. One field scouted this week had several plants that appeared to have frogeye leaf spot.
Frogeye leaf spot occurs primarily on leaves and is caused by a fungus. Lesions initially appear dark and water soaked, but with age, centers become light brown to light gray in color. Older lesions have a light center with a dark reddish-brown border.
Lesions can kill large areas of the leaf surface. Development is favored by warm, humid weather. Susceptible varieties may warrant foliar fungicide if weather is especially favorable for disease development.
Japanese beetles and striped blister beetles were also found feeding on soybean leaves. Treatment is justified when defoliation reaches 30 percent before bloom and 20 percent between bloom and pod fill.
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