Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
CANKER-WORM . Joel 1:4; Nah 3:15, Ex 17:16. This was one of the army of destroying insects by which the land of Judea was laid waste. It is thought that the original word means rather the locust in its larva or caterpillar state, when it is even more destructive than after it acquires wings and is about to fly away.