Western Bean Cutworm Status as of July 22

By Greg LaBarge, Fulton County

The week of July 22 saw a dramatic increase in Western Bean Cutworm Moth captures in traps across northern Ohio. Also found were eggs and first instar larvae.

There were a wide range of counts for the week. Bruce Clevenger, Extension Educator in Defiance County saw counts of 0-154 for the week on 7 different traps. A report for a local farmer was 204 for the week. The figure to the left are trap counts from three locations I have. The 2011 trap counts are peaking in a similar pattern to 2010.  In 2010 there was a dramatic decrease from July 26 to July 30 counts. We will check traps mid week to see if counts have dropped off.

On Thursday (July 21) Dr Andy Michel, Extension Entomologist and I were out in eastern Fulton County. We stopped at eight fields and found egg masses or larvae in five fields. In order to find these we had to look very hard, only finding a couple of egg masses or larval hatches in each field. Based on what we saw on Thursday we may find some larvae in many fields but very light infestations overall. Also we discussed the heat and it is generally felt this will be a deterrent to higher egg laying by female moths. Scouting next week will give us a true picture of the potential for infestation.

Peak flight and corn size are important to targeting scouting. Focus scouting on corn which is pretassel, the V9-V10 stage (around waist high). Also keep in mind genetics. You may find eggs and larvae in a field, but if you have  transgenic hybrids with the Cry1F gene will offer adequate to near-complete control of WBCW. These include Herculex I and Herculex Xtra, as well as SmartStax.  A new gene, Vip3A from Syngenta also offer control of WBCW.

Scouting procedures were in the 2011-20 issue of C.O.R.N.:

Scouting for eggs and larvae should begin when adult catches occur on consecutive nights.  Inspect 20 plants in 5 random locations throughout a field.  Female moths prefer to lay eggs on the uppermost leaves which are still vertical in orientation, so those leaves should be inspected thoroughly. They also will be on the upper side of the leaf.

During winter meetings we shared a video on scouting for WBCW eggs and larvae from Purdue. To review that video click here.

If western bean cutworm eggs are found, please contact your County Extension Educator.

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