Although the spongy moth Lymantria dispar (formerly called gypsy moth) is not yet established in Missouri, it is a species of serious concern for forest land owners, and natural resource management agencies.  The species is originally from Europe and Asia and accidentally introduced into the US at around 1868.  About 10 years after this introduction, the first outbreaks began around Boston and in 1890 the State and Federal Government began their attempts to eradicate the moth. These attempts were largely unsuccessful and the range of gypsy moth has continued to spread. Every year, isolated populations are discovered beyond the contiguous range of the gypsy moth but these populations are eradicated or they disappear without intervention. It is inevitable that gypsy moth will gain ground and continue to expand its range.

The spongy moth is known to feed on the foliage of hundreds of species of plants in North America but its most common hosts are oaks. Spongy moth hosts are located throughout most of the US but the highest concentrations of host trees are in the eastern and central hardwood forest regions. For this reason Missouri is particularly concerned with the threat that this moth poses. While small populations of the larva can defoliate a few branches this species can quickly breed and produce populations large enough to defoliate whole forests.

Identification:

Egg masses appear as 1.5 inch tan or buff-colored hairs on tree trunks, outdoor furniture, or on the side of buildings.  Spongy moth caterpillars change appearance as they grow.  Young caterpillars are black or brown and about ¼ inch in length.  As they grow, bumps develop along their backs along with coarse, black hairs. Each of the 11 sections of a developed caterpillar will have two colored spots, the first five pairs, blue, and the last six, red.  Mature caterpillars can be as long as 2
½ inches.  Spongy moths are seen only in midsummer.  Males are grayish brown and can fly; females are larger, whitish with black marks and cannot fly.

For a pdf copy of this factsheet : Gypsy Moth