Forest Tent Caterpillar

Malacosoma disstria

Native to North America, the forest tent caterpillar, Malacosoma disstria, strips the foliage from trees, builds cocoons on the sides of buildings, and becomes messy when crawling on sidewalks, patios, and driveways where they are frequently squashed.

Forest tent caterpillars are active from mid spring through early summer and are easily visible as they congregate on branches or tree trunks. Multiple years of defoliation can tax a tree’s energy storage, leaving it susceptible to further insect or disease problems.

Download Forest Tent Caterpillar Fact Sheet

Treatment Strategy

This insect can be extremely destructive to the aesthetics of plants and a real nuisance.  For these reasons, treatment with insecticides is often preferred. However, when choosing insecticides be sure to choose one that controls lepidopteron insects.  Most insecticides do not control these moth and butterfly insects.

Purchase Forest Tent Caterpillar Treatments Now!

Forest Tent Caterpillar Treatment Option 1

Sprayed treatments with insecticides such as Up-Star® Gold can provide excellent control. However, if treating a large tree, foliar applied treatments may be too environmentally risky. Wind drift and contact with non-target insects are common concerns, making soil-applied treatments the preferred method for many professional arborists.

Application Method – Foliar spray

DIY Equipment/Product Needed:

• Up-Star® Gold

• Hand pump sprayer with wand

• Gloves

• Safety Glasses

Forest Tent Caterpillar Treatment Option 2

Another less aggressive sprayed approach is Conserve® SC.   The active ingredient in Conserve® SCspinosid, is a naturally occurring bacterium found in soil. Conserve® SC can be applied as a foliar spray and is considered non-toxic to people, yet is effective on moth and butterfly insects, like forest tent caterpillars.

Application Method – Foliar spray

DIY Equipment/Product Needed:

• Conserve® SC

• Hand pump sprayer with wand

• Gloves

• Safety glasses

Forest Tent Caterpillar DIY Kit

Option 1

Application Method – Foliar spray

DIY Equipment/Product Needed:

• Up-Star® Gold

• Hand pump sprayer with wand

• Gloves

• Safety Glasses

Option 2

Application Method – Foliar spray

DIY Equipment/Product Needed:

• Conserve® SC

• Hand pump sprayer with wand

• Gloves

• Safety glasses

How Is It Spread?

Forest tent caterpillars have one generation per year. Larvae emerge in mid-spring and the caterpillars feed for about 5-6 weeks. In late spring and early summer, mature caterpillars move from their feeding sites in search of a protected area to pupate in their silky cocoons. Approximately two weeks later, adult forest tent caterpillar moths emerge and lay shiny, black egg masses around small twigs.

Susceptible Trees

A number of deciduous trees act as hosts including aspen, oak, birch, ash, maple, elm, basswood, water tupelo, sweetgum, red alder, willow, and cherry.

Symptoms

• Stripping of foliage from mid spring to early summer

• Shiny black egg masses are often visible encircling twigs.

• Young larvae are black, hairy and about 1/8 inch long, often visible in groups on twigs and trunks.

Lookalikes

Gypsy moth, Eastern tent caterpillar, Sawfiles

Related/Similar Problems

Gypsy moth, Eastern tent caterpillar, Sawfiles

Timing

Spring

Urgency

Moderate

Risk of Spreading

High

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