PestMedium Severity

Eastern Tent Caterpillar

Malacosoma americana (Lepidoptera: Lasiocampidae)

One of the most widespread defoliators of deciduous shade trees in eastern North America. Larvae create distinctive silk tents in limb crotches during spring feeding, distinguished from Fall Webworm which forms tents terminally on branches in late summer.

Peak Season: Larvae active spring through early summer, adults emerge mid-summer
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Eastern Tent Caterpillar showing characteristic tent webs and larvae

Identification & Symptoms

What to Look For

Large silk tents or nests constructed in limb crotches in spring
Progressive defoliation as larvae feed on tender leaf tissues
Entire trees may be covered with webbing in heavy infestations
All leaves devoured in severe cases
Egg masses appear as dark brown, shiny collars encircling twigs
White cocoons visible on tree trunks, fences, and other objects

Potential Damage

Feeding restricts tree's photosynthetic processes
Can cause complete defoliation of affected trees
Three successive years of defoliation can kill trees
Heavy webbing creates unsightly appearance
Stress predisposes trees to secondary problems

Lifecycle

Female moths lay 150-350 eggs in dark brown collars around twigs during June-July. Eggs overwinter and larvae emerge the following spring when leaves are half-inch long. Larvae build silk tents and feed for six weeks before migrating to pupate in white cocoons. Adults emerge after several weeks. One generation per year.

Professional Treatment Approach

1

Physical removal of tents while small in early spring

2

Systemic insecticide injection for large trees

3

Bacillus thuringiensis applications during early larval stages

4

Pruning and destroying egg masses during winter

5

Avoid planting pure stands of susceptible species

Recommended Mauget Products

Imicide

Professional-grade treatment specifically effective against eastern tent caterpillar.

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Dinocide

Professional-grade treatment specifically effective against eastern tent caterpillar.

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Need Professional Diagnosis?

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