Tuesday, August 11, 2015

Second summer generation Fall webworm egg masses spotted

    I was mowing around my pecan trees when I spotted several dime-sized egg masses deposited on the undersize of pecan leaves (photo at right). The eggs are very light green in color but are largely covered by a layer of white fluff. This is the start of a new Fall webworm colony. Female webworm moths lay their eggs in a cluster on the underside of a leaf then cover that egg mass with scales rubbed off of the moth's abdomen. The female moths cover their egg masses in this way to hide the eggs from egg parasites.

   Driving down the highway, I noticed that the 2015 spring brood of fall webworm on roadside trees was fairly large. And judging from the number of egg masses I've already seen, the fall brood will be even bigger. I even found two egg masses on a single pecan leaflet (photo at left).
   With recent rains, pecan weevils have started to emerge and we have already sprayed the pecan grove to control weevils and stinkbugs. It looks like our pesticide application will also help keep webworms in check. Additional weevil sprays later this month should control any additional webworm colonies that arise from egg masses deposited later in August.