Joel 1:4

"That which the palmer-worm hath left hath the locust eaten; and that which the locust hath left hath the canker-worm eaten; and that which the canker-worm hath left hath the caterpillar eaten."

The two great problems of interpretation encountered in this verse regard (1) the four different names applied to the destroying insects, and (2) the question of whether or not this was a literal infestation.

As to the four different names, they have been supposed to refer to the locust at various stages of its development, but the most thorough studies of that insect do not reveal four different phases in its life cycle. As Keil said, "These words never appear in simple plain prose,"[10] and all of them may therefore be poetic references to the same insect. "The four names are not names applied in natural history to four distinct species."[11]

The question about whether this was a literal disaster, or perhaps a symbolical depiction of some future event prophesied by Joel, is decided by Joel 1:3, where there is an undeniable reference to Exodus 10:2, with the mandatory deduction that this disaster was comparable to the Egyptian plagues, which, of course, were literal events.

The allegorical interpretation of these locusts, however, has been very attractive to whole generations of interpreters.

On the margin of the Greek Codex Marchalianus (Q) of the sixth century, the words for locusts in Joel 2:25 are identified with the Egyptians, Babylonians, Assyrians and Greeks ... According to Merx, Joel's locusts are supernatural apocalyptic creatures in Joel 1, and symbols of the invading armies of the end times in Joel 2.[12]

The denial that the locusts were a literal disaster is totally frustrated by "before our eyes" (Joel 1:16). That the recapitulation of the disaster in Joel 2 indeed has overtones of the end times can hardly be discounted, due principally to the manner of the apostle John's treatment of the locusts in Revelation 9.

The palmer-worm, locust, canker-worm, and caterpillar may therefore be understood in this chapter as saying that, "One swarm of locusts after another has invaded the land, and completely devoured its fruit."[13]

The notion that plagues in successive years are meant is from the mention of "the years that the locust hath eaten" (Joel 2:25); but, again, from Keil:

We cannot possibly think of the field and garden fruits of two successive years, because the fruits of the second year are not the leavings of the previous year, but have grown afresh in the year itself.[14]

Before leaving this verse, it is of interest that Deere translated the four names as, "shearer, swarmer, lapper, and devourer, describing four of the eighty or ninety species of locusts in the East."[15] This understanding of the terms as different kinds of locusts is widely accepted; but the view preferred here is that the words are poetic descriptions of wave after wave of the devouring insects.