Forest Tent Caterpillars Update

Uploaded by uvmext on 02/24/2022

Tags: maple  

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It appears as though the recent widespread defoliation event related to forest tent caterpillar has ended. According to the Vermont Department of Forest Parks and Recreation, there have been no reports of defoliation attributed to this native insect in 2019. This is in stark contrast to the roughly 70,000 acres of defoliation mapped in 2018. The dramatic decrease is typical of the "boom and bust" cycles previously observed. Cycles will usually last between 2-4 years in Vermont and occur roughly every 10-20 in some part of the state. The caterpillars can multiply rapidly and make their presence known by consuming large volumes of leaf matter. During the outbreak, it is not uncommon for wide areas of forest to appear brown and almost leafless from afar. The vast majority of trees will regrow new leaves to make up for the ones that have been lost. In rare cases some individuals have even been defoliated twice in the same summer without dying. At the end of an outbreak the caterpillar populations will crash as a result of a corresponding increase in several natural predators and natural controls. Most trees will recover after a few years of poor growth and this native insect will return to relative obscurity until the next outbreak.