Western tent caterpillars (Malacosoma sp.)This may be a banner year for tent caterpillar infestations on Antelope
Bitterbrush, Purshia tridentata (Pursh), fruit trees and ornamental
shrubs. But, please, don't grab up the chemicals to attack them. Think
before you spray!
This is a pest that can be looked at in several
ways. For one, they have been here long before us, and no matter how
many colonies you kill, they will still be here after we've gone out
among the stars-they may be pests, and not much fun to look at, but
they are survivors. On top of that, they are one of the favored targets
of tachinid flies, helpful insect parasites that are always looking for
a delicious host. Most often, if you spray tent caterpillars, you will
also kill the "Good Guys." Another point is, as adults, tent
caterpillars take to the wing as moths that are the favored prey for a
number of bats, nighthawks, Flammulated Owls and other night-time
insect feeders.
In the short-term view, tent caterpillars may
seem repulsive and cause damage to plants, but in the long run-which is
how Nature looks at things-they ain't so bad.

