Bagworms seemed to get off to a slow start this year in parts of Kansas.
But reports of their damage are increasing rapidly now at Kansas State University's campus-wide network of Research and Extension diagnostic labs. The "worms" themselves--as well as their appetites--are growing quickly.
On average, Kansas bagworms end their annual eating frenzy by mid-August. Each closes itself inside the bag it has been carrying and building on its back while feeding.
Until the worms are sealed away, however, control is still possible.
Summer's "lunch" for bagworms often includes eastern red cedars, junipers, arborvitae, spruces and pines. The larvae also attack such trees and shrubs as the willow, maple, oak, box elder, sycamore, poplar, locust, rose, barberry, pyracanthia, clematis, sumac, elm, cherry, quince pear, peach and blackberry.
K-State entomologist Bob Bauernfeind conducted a study last year, comparing the late-season results of applying Sevin, Diazinon, Dursban, Malathion and Orthene. Many experts recommend using only the stronger of these controls during August, but Bauernfeind got good results with every product.
He found, however, that thorough spray coverage to the point of run-off was vital for good results.
Once bagworms have sealed off their twiggy-looking cocoons, the only way to stop the insects from producing another generation of greenery-munching pests next year is to find, pick and dispose of the camouflaged bags.