CANKERWORM

cankerworm

(noun) green caterpillar of a geometrid moth; pest of various fruit and shade trees

Source: WordNet® 3.1

Etymology

Noun

cankerworm (plural cankerworms)

Either of two caterpillars, the larvae of geometrid moths, that are destructive to fruit, buds and leaves.

(figurative) A corrupting or destructive force.

Source: Wiktionary

Can"ker*worm`, n. (Zoöl.)

Definition: The larva of two species of geometrid moths which are very injurious to fruit and shade trees by eating, and often entirely destroying, the foliage. Other similar larvæ are also called cankerworms.

Note: The autumnal species (Anisopteryx pometaria) becomes adult late in autumn (after frosts) and in winter. The spring species (A. vernata) remains in the ground through the winter, and matures in early spring. Both have winged males and wingless females. The larvæ are similar in appearance and habits, and beling to the family of measuring worms or spanworms. These larvæ hatch from the eggs when the leaves being to expand in spring.

Source: Webster’s Unabridged Dictionary 1913 Edition