Beneficial or Nuisance?
The answer of course is both!
Tent caterpillars are one of several web-spinning caterpillars, which includes both gypsy moth and webworms. Tent caterpillars are natives to the east coast, and that means they have native predators after them. It is much more difficult for tent caterpillars to become a major nuisance because a variety of birds as well as insects eat them. Unlike gypsy moth caterpillars as they are not native and have no natural predators; most birds dislike the taste of gypsy caterpillars. Among the birds that eat tent caterpillars are robins, blue jays, red-winged blackbirds, and cardinals. Insects that feed on these caterpillars are various tiny braconid, ichneumonid, and chalcid wasps which helps regulate the population.
These caterpillars leave the tent every day to feed, they sometimes will have to go around the tree to find, fresh leaves. If the tree they are on is large, they may have to explore several branches before they find a meal. Eastern Tent Caterpillars have already figured out how to be most efficient; as they leave the nest tent, they leave a trail with a silken thread. Just like an ant trail other caterpillar will follow it to food. If there turns out to be no leaves, the caterpillar will tear the thread.
Yes, the nests can appear unsightly, however in most cases Eastern Tent Caterpillars do not cause irreparable harm to host trees. Typically, tent caterpillars defoliate a few branches and only actively feed for about six weeks. The nests the tent caterpillars design is basically the cocoon of the caterpillar. There is generally only one generation a season.
In the spring they especially favor plants like cherry, apple, and chokecherry, later they will move onto other leafy shade trees. Eastern tent caterpillar nests are commonly found on wild cherry, apple, and crabapple, but may be found on hawthorn, maple, peach, pear and plum as well.
The eastern tent caterpillar overwinters as an egg, within an egg mass of 150 to 400 eggs. These masses are covered with a shiny, black varnish-like material and encircle branches that are about pencil-size or smaller in diameter.
The caterpillars hatch about the time the buds begin to open, usually in early March. These insects are social; caterpillars from one egg mass stay together and spin a silken tent in a crotch of a tree. Caterpillars from two or more egg masses may unite to form one large colony. During the heat of the day or rainy weather, the caterpillars remain within the tent. They emerge to feed on leaves in the early morning, evening, or at night when it is not too cold.
Controlling tent caterpillar populations:
- Insecticides are generally ineffective against mature larvae (i.e. caterpillars).
- Removal and destruction of the egg masses from shade and fruit trees during the winter will help contain the population.
- In the early spring, small tents can be removed and destroyed by hand.
- Larger tents may be pruned out and destroyed or removed by winding the nest upon the end of a stick.
- Burning the tents out with a torch is not recommended since this can easily damage the tree.
Restrict caterpillar movement and cut off access to feeding areas with sticky tree bands. Using an insecticide that contains neem oil will disrupt growth. It also is non-toxic to honeybees and other beneficial insects. Fast-acting botanical insecticides need to be alast resort, although there are fewer harmful side effects as compared to chemical insecticides. Depending on the amount of egg masses along with predator populations, Eastern Tent Caterpillar populations will wax and wane.
If the nests are too high to comfortably remove calling Advanced Tree Care LLC for help is always a good choice.