We have found a few corn fields in the Bothwell and Strathroy area that have had above threshold numbers of WBC eggs. I strongly recommend that late planted corn fields that are not in full tassel yet be scouted this week and next. Given that we are at or close to peak moth flight, that means there are a lot more moths out, dating, mating and laying eggs. They will be most attracted to later planted corn fields that are not in full tassel or early planted dry bean fields at this point. Not all fields will have WBC activity in them so do not spray corn fields with insecticide unless the egg mass threshold has been reached.
Based on high trap catches this past week, here are other areas that should be scouted: Courtland, Ben Miller, Blyth,Varna, Seaforth, Mitchell, Watford
2 thoughts on “ALERT- WBC threshold has been reached in some corn fields”
Wanting some clarification on whether or not hybrids that have the Herculex trait will need to be sprayed if they reach the threshold levels.
Herculex and SmartStax hybrids (containing Cry1F) will provide enough protection to equal one spray application. I do not recommend spraying Cry1F fields at this time. However, research is currently underway to determine if a threshold may need to be created for Cry1F hybrids in cases when egg laying is extremely high in those fields. But at this time, I believe it would not be economic to spray fields with hybrids containing Cry1F. Keep in mind however that the non Bt refuge will see damage in these fields if threshold is reached in the refuge.
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