palmerworm noun2 •A gelechiid moth, Dichomeris ligulella, destructive to fruit trees. •(no longer used) Any small, terrestrial invertebrate, usually an agricultural pest and having many legs and a hairy body.And I will restore to you the years that the locust hath eaten, the cankerworm, and the caterpiller, and the palmerworm, my great army which I sent among you. — 1611 formspalmerworms