Have You Seen Tent Caterpillars On Your Trees?

The Eastern Tent Caterpillar, you can't miss them, due to the unsightly, clinging tent that is their residence after hatch.

In the spring, the caterpillars feed on the young leaves of oak, aspen, maple and cherry and often times will almost completely defoliate the host tree.  The tree will rarely die unless it is wakened by other aspects of stress in addition to the defoliation. The tree will grow a second set of leaves, although smaller.

The adult moth is a buff color with a brown band across the wings. The wing span about 1".

Once caterpillar feeding stops, they spin their cocoon and about two weeks later, sometime between late June and early July, flights of tent caterpillar moths will occur. The moths do not feed. They mate, lay the eggs (for next springs caterpillar), and die.

So How Do You Keep Your Trees Healthy?

 The Tent Caterpillar is native to Michigan and so fortunately there are native natural controls.
One includes an effective parasite known as "The Friendly Fly". This guy lays his eggs on the tent caterpillar cocoon, preventing them from developing into adult moths.

These "friendly flies" do not bite, thankfully, because they do seem to want to land on you!

Several species of other flies and wasps parasitize the eggs, larvae and pupae of the forest tent caterpillars. Predatory flies, beetles, ants, spiders, birds, wood frogs, deer mice, skunks, bears and toads also feed on forest tent caterpillars.

In the spring, spraying Bt, (a biological insecticide), on the leaves can help protect foliage without affecting natural enemies. Since we are opposed of other insecticides, the only other option is to destroy the batch of caterpillars manually. The branch can be pruned off with the attached tent and  burned. Any caterpillars seen on the tree branches and trunk can be  squished...we recommend wearing gloves!

Now, if you have a tree that was affected by these hungry caterpillars,  if at all possible, see that the tree gets at least an inch of water per week during the growing season and possibly apply a slow release fertilizer.

Woodlot owners should focus on keeping their forest healthy by periodically removing trees that are  in poor condition. This will also increase the amount of sunlight available to remaining trees and reduce competition for water and nutrients. This is where we can come in and can offer suggestions for a healthy thriving woodlot.