Control? Pesticide? Nah. Being this late in the year, the leaves are beginning their shutdown/fall off routine, aren’t providing much in the way of food for the tree anymore, so if some fall or get eaten prematurally, I don’t sweat it. I’ve always heard an organic control is to take a stick and tear apart the web, exposing the caterpillars to passing birds for a quick take-out meal, but I’ve never seen a bird indulge. Maybe someone (not me) that knows birds could shed some light here.
Those disgusting silky web cocoons on branches on the sides of the road you’ve been seeing? Fall Webworm, (Hyphantria cunea (Drury)). I’ve been getting asked about it quite a bit, that’s why I bring it up. They were a random little unidentifiable white moth in May and June, with the females laying their eggs on the undersides of the leaves. The webs form on the tips of the branches, as the caterpillar eats its way down the branch. Many larvae may be seen in one web.Pupation occurs in the ground or in the leaf litter beneath the tree. They are quite prevelant in Crabapples, cherries, Birches, and Lilacs, but I’ve even seen them in Elms along the road.