ENTFACT-423: Eastern Tent Caterpillar  |  Download PDF. Unlik e the tent caterpillar, fa ll webworm nests are located at the ends of the branches and their loosely woven webs enclose foliage while the tents of the eastern tent caterp illar do not. Tent caterpillars keep each other warm. Egg masses remain on the trees during most of the summer, fall, and winter. Defoliation of trees, building of unsightly silken nests in trees, and wandering caterpillars crawling over plants, walkways, and roads cause this insect to be a pest in the late spring and early summer.Eastern tent caterpillar nests are commonly found on wild cherry, apple, and crabapple, but may be found on hawthorn, maple, cherry, p… Cherry leaves are cyanogenic and the caterpillars regurgitate cyanide-laden juices when disturbed. Tent caterpillars are among the most social of larvae. G.J. Few birds other than cuckoos find the hairy caterpillars palatable. Studies show that below 15 °C (59 °F), the caterpillars are unable to process the food in their guts. Because the early spring weather is often cold, the caterpillars rely on the heat of the sun to elevate their body temperatures to levels that allow them to digest their food. The tent of this species is among the largest built by any tent caterpillar. The tent has openings to allow them to enter and exit. Such bouts of thrashing, which may be initiated by a single caterpillar, radiate rapidly through the colony and may result in group displays involving dozens of caterpillars. CAUTION! As the larvae feed on the foliage, they increase the size of the web until it is a foot or more in length. Unlike the tent caterpillar, fall webworm nests are located at the ends of the branches and their loosely woven webs enclose foliage while the tents of the eastern tent caterpillar do not. In The silk is laid down under slight tension and it eventually contracts, causing the newly spun layer of silk to separate from the next layer. The eggs will hatch next spring. It is constructed in the crotch of the host tree and is typically oriented with the broadest wall facing the southeast to take advantage of the morning sun. In another study, the necropsy of a mare fed eastern tent caterpillars showed fragments of the caterpillar's setae had embedded in the gut wall, and it was hypothesized that they may facilitate the passage of infective agents from the horse's gut into the bloodstream and then to the placenta, triggering abortion. The tents are multifunctional. Luckily, tent caterpillars are pretty easy to bat off, whether you opt for an insecticide or handy home remedy. Research   /   Figure 4. The eastern tent caterpillar, Malacosoma americanum, is a pest native to North America. The conspicuous white nests of the eastern tent caterpillar in the forks of branches during the month of May show everybody that the insect is present. Defoliation of trees, building of unsightly silken nests in trees, and wandering caterpillars crawling over plants, walkways, and roads cause this insect to be a pest in the late spring and early summer. Various tent caterpillar species exist, including forest tent caterpillars (Malacosoma disstria), western tent caterpillars (Malacosoma californicum) and eastern tent caterpillars (Malacosoma americanum), but all species require the same mechanical, biological and chemical control methods. Natural enemies play an important role in reducing eastern tent caterpillar numbers in most years. They emerge to feed on leaves in the early morning, evening, or at night when it is not too cold. 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