Albert Barnes Commentary Psalms 78:46

"He gave also their increase unto the caterpillar, And their labor unto the locust." — Psalms 78:46 (ASV)

He gave also their increase unto the caterpillar - The increase or the produce of their fields (Exodus 10:12–14). The word חסיל châsı̂yl - is supposed to denote a species of locust rather than the caterpillar. It literally means the devourer. In our version, however, it is uniformly rendered caterpillar as here; 1 Kings 8:37; 2 Chronicles 6:28; Isaiah 33:4; Joel 1:4; Joel 2:25. It occurs nowhere else.

And their labor unto the locust - The fruit of their labor; the harvests in their fields.