There are many types of caterpillars that attack mature trees by
eating their leaves and defoliating them. The repeated
defoliation of a mature tree places it under significant stress
and makes the tree more vulnerable to other diseases or
aggressive insects such as boring insects, which can cause
mortality. At the first sign of caterpillars on the tree, spray
with Garden Insect Spray with Spinosad or Bug Buster Pyrethrin
Insect Spray and repeat the spray every two to three weeks,
until the feeding period has ended. In the fall, remove any
visible egg nests or spray them with Horticultural Oil Insect
Spray. In the spring, place a sticky TreeHelp Bug Bandon the
trunk of the tree to prevent the caterpillars from migrating
from the ground up towards the tree’s leaves. In the early
spring, treat trees that are too tall to spray with Once-A-Year
Insecticidal Drench w/Merit, to provide insect protection
throughout the growing season.