OCR Text |
Show Take action now vs. tent critters The tent caterpillar, which caused serious damage to some Utah trees last year, is beginning to appear and now is the time for tree owners to take action, advises Jay Kan-en, Utah State University Extension Ex-tension entomologist. "We had a lot of tent caterpillars last year and we may be hitting the peak this year," Karren said. The tent caterpillar feeds on a wide variety of forest, fruit and shade trees in the state, including poplar, cottonwood, plum, cherry, choke cherry, aspen, alder, shad-bush, shad-bush, willow, birch and apple among others. "Too often people wait until the damage is done and then call to see what they can do about the caterpillars," cater-pillars," Karren said. "The time to spray is just after the eggs hatch, as soon as the tents or the caterpillars themselves are noticed." They're easier to kill when they're small so early treatment is a good idea to prevent as much damage dam-age as possible. Chemical sprays include Dursban, Sevin, Orthene, diazinon, malathion and Marlate. Bacillus thuringiensis, sold as Dipel, Thuricide, Bactur, Biotrol, SOK-Bt and others is a bacterial disease of caterpillars that must be ingested to be effective. As with all pesticides, read and follow label instructions. Cultural control consists of removing re-moving the young larvae and tents before signifcant injury occurs, but Karren said that is feasible only on small trees and even then can be time-consuming. There are several species of tent caterpillar in Utah, but their identification identi-fication is complicated by the presence pre-sence of several subspecies, all of which differ somewhat in color. Their life cycles and the damage they produce are similar, though Karren says. The tent caterpillar passes the winter in the egg shells and emerges in the spring, chewing its way out of the eggs about the time new leaves appear. The young larvae are gregarious. Some species construct web tents, others cluster on limbs when they're not feeding. Tent caterpillars should not be confused with box elder leafrol-lers, leafrol-lers, which emerge about the same time. The leafrollers appear singly and don't make tents. The tent caterpillar is fuzzy and colorful while the leafroller is a dull green and not as fuzzy. "Healthy trees usually can withstand with-stand heavy infestations of tent caterpillars for two or three years without suffering permanent injury," in-jury," Karren said. "But trees under other forms of stress or young, recently planted trees can be severely damaged from a single infestation." |