Thursday, July 10, 2014

Insect Pressure Low in Area Fields; Check Threshold Levels of Japanese Beetles Before Spraying

Contact: Jill Scheidt, agronomy specialist
Headquartered at Barton County Extension Center
Tel: (417) 682-3579

Expert Advice from the Field …

LAMAR, Mo. – Jill Scheidt, agronomy specialist with University of Missouri Extension in Barton County, scouted fields ten miles east of Lamar and north of Golden City on July 2 for the crop scouting program. Scheidt offers this advice from the field.

Corn is in pollination stage; pollination is complete in most fields and pollinated well. Threshold levels for Japanese beetle in corn are three or more beetles per plant clipping green silks to one-half an inch. Once pollination is over, there is no need to control Japanese beetle in corn. “It is typically not economical to spray because Japanese beetles come in several flights, resulting in multiple insecticide applications,” said Scheidt.

Soybeans are in beginning bloom and the first trifoliate. “Japanese beetle and grasshopper seem to be more attracted to more mature plants, but generally do not require treatment,” said Scheidt.  Threshold levels for Japanese beetle and any leaf-feeding insect in soybean are 30 percent defoliation before bloom and 20 percent defoliation during and after bloom.  “I am not seeing a need to spray insecticides in any fields right now. For control of Japanese beetle in landscapes and garden use Sevin or Malathion. Remember beneficial insects will be killed with insecticides,” said Scheidt.

“Japanese beetle populations should start to decrease over the next 3 weeks and beetles should be gone by August. So far, I have not seen any fields at threshold level for Japanese beetles and there is no need to spray an insecticide,” said Scheidt.


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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