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WHITEMARKED TUSSOCK MOTH
Mature larva of the WHITEMARKED TUSSOCK MOTH. |
| Other |
Tussock moth |
| Species |
Orgyia leucostigma |
| Common Hosts: |
Apple Malus pumila
Elm Ulmus spp.
Laurel oak Quercus laurifolia
Live oak Quercus virginiana
Mimosa Albizzia julibrissin
Pyracantha
Pyracantha cocinnea
Redbud Cercis canadensis
Water oak Quercus nigra
Other hardwoods |
Description |
Adult -- male has brownish-gray head and body; front pair of wings same color plus darker wavy bands and 2 prominent white spots; wingspan approximately 30 mm. Female is gray and wingless.
Pupa -- size of adult; brown; enclosed in a tan to gray silk cocoon.
Larva -- size variable, approximately 35 mm long when mature; coral red head, yellow to cream color body with black stripes on back, 2 long tufts of dark hair over head, 1 tuft on in the rear, and 4 short tufts of yellow to white hairs on back.
Egg -- gray to white hard, frothy mat of eggs on female's old cocoon. |
Importance |
A common spring pest, especially around oak-populated areas. Severe defoliation for 2 or more consecutive years will stress trees. Death may result if other stress factors also weaken the trees. Its habit of falling or spinning out of trees is unnerving to most people. |
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Larvae emerge from eggs during leaf expansion in spring. They disperse readily on silk strands while still young. Older larvae are active crawlers. Pupation occurs in any shaded and protective site. Generally, the 2nd or 3rd generations are not as noticeable as the 1st or spring generation. Overwinter as eggs laid on the females' cocoons. |
| Number of Generations |
2 or 3 generations per year. |
Signs
of Infestation |
Loss of foliage. Falling frass (dark pellets of caterpillar excrement). Cocoons in bark crevices, under overhangs of buildings, and other shaded, protective sites. Crown thinning and/or branch dieback. |
Control |
- Predators, parasites, diseases, and unfavorable weather usually keep caterpillar populations at low levels. Outbreaks do occur, but generally subside after 2 or 3 years. Promote tree vigor and health to aid in the recovery from defoliation. Use an approved insecticide for high-value trees or for extremely damaging larval populations. Caution: rash-like symptoms have been reported by some individuals exposed to repeated contact with caterpillar hairs.
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Bulletin No. 196-A | Printed October, 1983 | Contact the
Forest Health Section 
