What do tent caterpillars do to trees

While tent caterpillars can nearly defoliate a tree when numerous, the tree will usually recover and put out a new crop of leaves.

In the landscape, however, nests can become an eyesore, particularly when exposed by excessive defoliation. The silken nests are built in the crotches of limbs and can become quite large. Larvae cause considerable concern when they begin to wander to protected places to pupate. Frequently they are seen crawling on other types of plants, walkways, and storage buildings. They are a nuisance and can create a mess when they are squashed on driveways, sidewalks, and patios.

But keep in mind that no additional feeding or damage is done by the wandering caterpillars. Eastern tent caterpillar nests are frequently confused with fall webworm nests. Unlike the tent caterpillar, fall webworm nests are located at the ends of the branches and their loosely woven webs enclose foliage while the tents of the eastern tent caterpillar do not.

While there may be some overlap, fall webworm generally occurs later in the season. The eastern tent caterpillar overwinters as an egg, within an egg mass of to 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. The caterpillars hatch in the spring, and they congregate to create a communal nest in a tree where they retreat during the evening and during inclement weather, emerging to feed on the foliage.

It takes about six weeks from when they emerge from their eggs to when they head off to form their cocoons on trees, buildings, and fences. As the caterpillars grow, they chomp on the foliage of trees and can even defoliate the entire thing in large enough groups.

Once they leave their nests and head out alone to pupate, they stop eating. A few weeks after they form their cocoons, the moths emerge to mate. Most moths of this variety are a dull brown color and have a wingspan of about two inches. Infestations tend to occur every decade or so, and last for a year or two before the moths move on to other locations, or predators drive the numbers back down.

These days, many experts recommend simply leaving these wigglers alone. Even if the caterpillars completely defoliate a tree, it should recover after the pests take off. Plus, these insects are an important part of the natural environment and they have lots of natural predators. The larvae and adults serve as a food source for dozens of bird species, bats, lizards, and other critters.

Second, trees that are already stressed from drought, disease, or other pests might not be able to withstand an infestation. Broodmares can unintentionally eat the caterpillars, and the hair covering the larvae breaks off in their digestive tracts.

This wreaks havoc that can cause them to abort their foals or give birth to weak foals. I want to remind you, though, that they are an important food source for many animals and other insects. Their frass, or poop, is also a good source of fertilizer. After being defoliated, most trees bounce back with more leaves than ever. Your best bet to get a handle on these pests is simply to remove them physically. There are several ways to do this. You can also use a broom to sweep out the nests onto a tarp, and then bag and dispose of the bugs.

Do not, under any circumstances, try to torch the nests. They will burst into flame and, as they detach from the tree, they become fiery flags flapping in the branches.

Not only is this a serious fire hazard, but it can harm the tree, too. To remove the abandoned nests, use a broom or a strong spray of water from the hose. The forest tent caterpillar Malacosoma disstria is native to North America. It is one of three tent caterpillar species, which also include the eastern tent caterpillar Malacosoma americanum and the western tent caterpillar Malacosoma californicum pluviale.

It has several natural predators such as ants, birds, vespid or yellowjacket wasps and parasitic wasps. Forest tent caterpillar top: adult male moth; right: adult female moth; bottom: caterpillar. Larger image. Research conducted by scientists at the Canadian Forest Service CFS has led to a number of insights into the forest tent caterpillar.

Through the Canadian Forest Service, Natural Resources Canada collaborates with provincial governments in Alberta, Saskatchewan, Ontario and Quebec as well as university partners, including the University of Alberta, MacEwan University and Concordia University, researching how the growth of an outbreak is affected by young larvae mortality and how the stage of an outbreak impacts moth flight patterns.

LFS tent caterpillars. Tent caterpillars inside a tree tent. Third party submitted. Although these caterpillars may eat just about all of the leaves on the tree, the damage is rarely permanent. In many cases, trees that lost their leaves early in the spring can regrow them leaves in July, after tent caterpillars have stopped feeding.

Healthy trees can survive two or three years of total defoliation. That doesn't mean the loss of leaves to these hungry caterpillars is completely safe for a tree. It does reduce its vigor and makes it more vulnerable to pests and diseases. Nonetheless, I have seen many wild cherry trees laid completely bare by tent caterpillars, then recovering well and growing into healthy mature trees.

There are two species of tent caterpillars. The eastern tent caterpillar, which is by far the most common on Staten Island, has a white stripe down the center of its back, with spots along its sides and long hairy bristles. The forest tent caterpillar has white spots down the midline of its back, with light blue stripes on either side.