Southwest Missouri Field Crop Report for July 24, 2013

Contact: Jill Scheidt, agronomy specialist

Tel: (417) 682-3579

E-mail: scheidtjk@missouri.edu

LAMAR, Mo. –Jill Scheidt, agronomy specialist with University of Missouri Extension in Barton County, scouted area fields on July 24 to prepare this week’s field scouting report.

“In fields that received rain, the crops look refreshed from the dry conditions.  Some lodging or leaning has occurred in the corn from high winds,” said Scheidt.

This week, no Japanese beetle feeding has been seen on the silks.  Threshold levels for Japanese beetle in corn are when 3 or more beetles are clipping green silks, to less than half-inch. 

“If corn is over 50 percent complete with pollination, it is not economical to treat Japanese beetles because the threat of kernels not being pollinated is minimal.  A high rate of Hero is recommended to treat Japanese beetles,” said Scheidt.

Chinch bugs have been seen in Vernon County.  They usually feed on edges of corn fields near wheat fields.  Chinch bugs suck sap from corn stalks causing them to wilt and the plant not to yield.  They prefer hot, dry weather.

Treatment is justified when 2-3 percent of plants show damage; Warrior II, Cobalt or Lorsban are recommended by themselves or with mixtures.  Treatment is usually only needed on field edges.

“Japanese beetle and grasshopper feeding were still seen in soybeans, but not at threshold level.  Grasshopper feeding should decrease with rainfall because they prefer hot, dry weather,” said Scheidt.

Defoliation threshold levels in soybeans are 30 percent defoliation before bloom and 20 percent defoliation during or after bloom. 

“Window pane feeding was seen on soybean leaves from second generation bean leaf beetles.  Second generation bean leaf beetles do not cause economic damage that require treatment, so window pane feeding is nothing to worry about,” said Scheidt.

In addition, Scheidt says some false chinch bug feeding has been seen in Vernon County.  False chinch bug suck sap from soybeans and can eventually kill them.  They are usually in weedy areas of the field and are most active in hot, dry weather. 

Warrior II, Cobalt or Lorsban work well to control false chinch bug.  Spot or edge treatment is usually only required; treat when 2-3 percent of plants are wilting or damaged. 

MORE INFORMATION

The weekly field scouting report is sponsored by University of Missouri Extension and Barton County Extension. For more information on this scouting report, or to learn how to receive it a week earlier by telephone, contact the MU Extension Center in Barton County, (417) 682-3579.

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