Over the past week or so I have found cankerworms here and there. A few on a maple along the greenway. A couple dangling from a willow oak on campus. Today I found a small cankerworm tromping across some gloomy scales.
I wonder if the snow we had on March 12 this year, around when I thought cankerworms would be hatching, might have killed some. Leaves and flowers on many trees and shrubs had already flushed and were damaged by the snow. Maybe cankerworms were about to hatch and were in a vulnerable state.
Alternatively, it could just be a low cankerworm year. Cankerworms live in New England and Canada so it is hard to believe a little snow would hurt them. I did not monitor adults this year but my friend Derek Johnson at VCU probably did. His lab just published a new threshold relating adult captures to likelihood of defoliation by larvae.
In any case, here they are we will see how the population develops.