Tent Caterpillars

Identification

Size: Tent caterpillars can vary in size depending on the species and stage of development. They typically range from about 2 to 3 centimetres (0.8 to 1.2 inches) in length.

Color: Tent caterpillars can have a variety of colours, but they commonly display black or brown bodies with lighter-coloured markings. Some species may have additional distinctive features, such as stripes or spots.

Description: Tent caterpillars are moth larvae that belong to the family Lasiocampidae. They construct silk tents or webs in the branches or forks of trees, which serve as their shelter and protection. The tents are easily recognizable and can be quite large, accommodating hundreds or even thousands of caterpillars.

Tent caterpillars typically emerge in early spring and feed on the leaves of various deciduous trees, such as cherry, apple, plum, or oak. They are most active during the day, congregating and feeding together within their tents. As they grow, the caterpillars moult several times, shedding their old skins and increasing in size.

Identifying tent caterpillars is relatively straightforward due to their distinct characteristics:

Silk tents: Look for the presence of silk tents in the branches or forks of trees. These tents can vary in size and shape but are typically large enough to be noticeable from a distance. They serve as the primary shelter for the caterpillars and can often be found in clusters.
Group behaviour: Tent caterpillars display social behaviour, often feeding and moving together within their silk tents. Observing a group of caterpillars congregating and feeding in a tent is a clear indication of their presence.
Caterpillar appearance: Tent caterpillars have distinctive physical features. They typically have hairy bodies, with colours ranging from black to brown, and may exhibit lighter-coloured markings, stripes, or spots. Their bodies are cylindrical and segmented, with three pairs of true legs near the head and several pairs of fleshy prolegs along the abdomen.

Silk tents: The most obvious sign of tent caterpillars is the presence of silk tents in the branches or forks of trees. These tents can be quite large and easily visible, resembling silk webbing or nests. Look for clusters of tents, especially in the early spring when the caterpillars are most active.

Defoliation: Tent caterpillars are voracious feeders and can quickly defoliate trees. If you notice significant leaf loss on your trees, particularly on deciduous species like cherry, apple, or oak, it may indicate the presence of tent caterpillars. They tend to eat the leaves along the branches and leave behind bare twigs.

Caterpillar activity: Observing the actual caterpillars can confirm their presence. Tent caterpillars are most active during the day and can often be seen congregating and moving together within their tents. They have distinctive appearances, with hairy bodies and colours ranging from black to brown, often with lighter markings.

While complete prevention of tent caterpillars can be challenging, there are some steps you can take to minimize their impact:

Prune and remove egg masses: In late fall or winter, inspect your trees for the presence of tent caterpillar egg masses. These masses appear as small, dark, foam-like structures attached to twigs. Carefully remove and destroy these egg masses to reduce the number of caterpillars in the following season.
Physical removal: If you spot silk tents on your trees, you can physically remove them by carefully cutting and disposing of the affected branches. Be sure to perform this task during the early morning or late evening when the caterpillars are inside the tents.

Natural predators: Encourage the presence of natural predators that feed on tent caterpillars, such as birds, parasitic wasps, or predatory insects. Create an environment that attracts these beneficial organisms, such as providing nesting boxes for birds or planting nectar-rich flowers to attract beneficial insects.
Tree health maintenance: Keep your trees healthy and vigorous through proper watering, fertilization, and pruning. Healthy trees are more resistant to tent caterpillar infestations and can recover more quickly from damage.

By being vigilant and taking proactive measures to manage tent caterpillars, you can help protect your trees and minimize the impact of their feeding habits on your landscape.