Western Bean Cutworm Counts Continue to Rise

We are starting to see an increase in moth catches in our WBC trap network though we are still behind compared to last year.  Last year by this week we were catching 10 moths per trap.  We are not close to that yet.  However, things could change quickly.  Storm fronts can help bring in large masses of moths from other locations.  The big concern is that the corn crop is starting to approach the ideal growth stages for moths to lay their eggs in.  Moths prefer corn that is in the “pretassel” stages before the plant is fully tasseling and shedding pollen.  Much of the corn crop is approaching that pretassel stage now.  Larvae that hatch and try to develop on corn plants that are too young (ie. don’t have a tassel at least developing in the whorl yet) will die in a few days time.

So egg mass scouting should begin in fields that are more advanced in their area.  Also if you know of traps that are in the area that have been catching some moths, those are more apt to have some egg laying activity.  To help you scout for WBC eggs, here is the link to scouting video we developed last year http://bautebugblog.com/category/scouting-video/

Also, we are looking for fields with lots of eggs again this year so we can collect them to infest our research plots.  If you find fields that have a decent number of eggs, we’d be happy to take them out of your fields for you.  Here is a link to a pdf showing what the eggs look like and who to contact if you find some.  Wanted WBC Eggs

And finally, if you haven’t been checking out our weekly WBC trap maps yet, here is a link to them as well.  Ontario WBC Trap Network Maps.  You can find both the cumulative map as well as the weekly trap count map for each region.  A new addition is a map showing the range of corn growth stages for each county.  Thanks to all of the company reps who are sending us the growth stage data to map and thanks to Laresco for creating the map for us.  We have developed a special growth stage chart to help describe more of the  “pretassel” and “tasseling” stages of corn rather than just call it all VT.  Here is a link to the Detailed Corn Growth Stage Scale for WBC Observations.

Next blog on WBC will include thresholds and larvae and eggmass look a likes.