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Mar 26

Caterpillars take over local oak trees

Posted on March 26, 2016 at 12:02 pm by Clay Curtin

Native oak trees are a large component of Menlo Park’s urban forest. Similar to other tree species, the coast live oak (Quercus agrifolia) is susceptible to a host of pests and disease. One primary pest is the tussock moth, which emerges in the spring to feed on the tree’s foliage. In addition to tree damage, they also cause a health concern for people enjoying the shade. These non-poisonous caterpillars have prickly hairs, which serve as a defense mechanism, and can cause skin irritations. Caterpillars in oak trees near the Menlo Children’s Center playground have sparked reports of rashes and skin irritations on children who handle them. The playgrounds have been power washed, but new caterpillars appear daily. Friday morning, March 25, the oak trees were treated with Bt-k (Bacillus thuringiensis, kurstaki), a naturally occurring soil bacteria used for controlling leaf eating caterpillars on trees and vegetables. Compliant with the City’s Integrated Pest Management Policy, BT-k is harmless to humans, animals and other beneficial insects. It is organic and biodegrades quickly in sunlight. The treatment and additional power washing occurred during the center’s spring break to limit exposure and minimize programming interruptions.

tussock moth