Species: Malacosoma americanum (eastern tent caterpillar); Malacosoma disstria (forest tent caterpillar)
Eastern Tent Caterpillar
Forest Tent Caterpillar Pictures
Tent Caterpillars as Pests
Note: Before destroying webbing in trees, make sure that you are
dealing with a pest - not a beneficial insect. There are Psocids called Tree
Cattle or Bark Lice that do not harm plants but are, instead, beneficial to
their host tree.
The tent caterpillar is the common name for the larvae member of many of the moth family. There are twenty six species found around the world, six of which are found in North America. Two species of the tent caterpillar the
Eastern Tent Caterpillar and the Forest Tent
Caterpillar, are a nuisance all over North America. Tent caterpillar outbreaks can occur every decade, can last two to four years and are a cause of major concern. When caterpillar populations explode they can cause damage to trees over hundreds of acres at a time.
Tent Caterpillars as a Pest
The eastern tent caterpillar prefers black cherry, choke cherry and scrub apple trees as well as Hawthorne, maple, cherry, peach, pear and plum trees. When in large numbers, they can defoliate (eat all the leaves) many fruit, deciduous and shade trees.
The forest tent caterpillar prefers sugar maple, popular, ash, oak, birch, red gum and black gum trees. They often feed in early spring destroying tree buds that are just blooming. Although defoliation of the tree occurs, they rarely kill trees except those already weakened and diseased.
Systemic sprays containing Acephate can be used but
simply removing affected branches or offending webs is more effective. As
stated above, defoliation by tent caterpillars is rarely the cause of a tree's
death; diseased or otherwise unhealthy or weakened plants are more likely to be
effected by these moth larvae.
Eastern Tent Caterpillar Description
The eastern tent caterpillar has a 2-2 ˝ inch long black body with a white stripe down it back and small oval blue spots on its sides. Its body is covered in long fine brown bristly hairs. After emerging from its cocoon, female moths have a dull reddish-brown body and a wing size on 1 ˝ -2 inches. Male moths are smaller than the female. Both have white parallel lines on their front wings.
Forest Tent Caterpillar Description
The forest tent caterpillar are around 2 inches in length and have a pale grayish-blue body with fine orange black lines and white spots on its back. Long bristles make them look furry. Adult moths are a light grayish-brown or tan with brown lines on its front wings. Females have a wing span on 1-1 ˝ inches.
During early spring, the female moth lays a mass of 150-300 eggs around small tree branches and covers them with a shiny black material called spumaline which prevents the eggs from drying out. It also protects the eggs from small wasps that put parasites in the eggs. After a few weeks, the eastern tent caterpillar emerges from their eggs and begins creating their tent. The tent is made of a silky web-like material and constructed in the crotches of limbs in spots where it catches the early morning sun. The tent increases in size up to a foot in length as the caterpillars feed on foliage. A very social caterpillar, eastern tent caterpillars from two or more egg masses will unite to form one large colony emerging from their tent to feed on leaves in the early morning, evening or at night when it is not too cold. When exploring for food, the eastern tent caterpillar leaves an exploratory pheromone trail when passing over branches so they can find their way back to the tent and so that the other caterpillars will find food easily. The larvae only leave their tents to feed and after six to seven weeks, they will find a suitable place to spin their cocoon. Each cocoon is double layered and composed of a whitish silk filled with a yellow powder. After ten days to two weeks, the eastern tent caterpillar completes the larval development and emerges as a moth. Female moths stay in their cocoon for two weeks during which she secretes a pheromone that draws males to her. Once mated, the female deposits her eggs around the circumference of a branch and the cycle starts all over again. The female moth dies soon after laying her eggs. Only one generation is created per year.
The female forest tent caterpillar, or the North American Moth, lays around 300 eggs in the same fashion as the eastern tent caterpillar, around the circumference of a tree branch covered in spumaline that prevents the eggs from freezing in the winter. After emerging from their eggs, they do not make tents, but weave silky web-like sheets where they live together. The larvae (caterpillar) lay down strands of silk as they move over branches and use them to travel on. They live in deciduous trees and strip the leaves after emerging from their eggs. The movements of the forest tent caterpillar are commonly referred to as “army-like” because they move in single file along the lines of web they have made. After five to six weeks they search for a place to weave their cocoon. The cocoon is usually constructed in a folded leaf, under bark or in a very sheltered place. They emerge as moths ten days later and only live for a few days.
• The nest of the eastern tent caterpillar is often confused with the webworm nest. The difference between the two is the eastern tent caterpillar builds its nest in the crotches of tree limbs while the webworm builds it nest at the ends of limbs and has foliage woven into its nest.
• Predators of tent caterpillars are birds, turtles, fish and other insect eaters.
• The eastern tent caterpillar will build a single large tent occupied throughout the larvae stage while other caterpillars build multiple tents and then abandon them.
Tent caterpillar pictures are grouped in three separate categories:
Pest Controlling Pests
and Animals Pest Control Supplies