On reading that it sounds like hoards of thrips are gobbling up everything in sight
They're teeny tiny things and slurp up plant juices, they don't chew things up and swallow them and the plants they attack depends on the species of thrips. There are some, like western flower thrips (Frankliniella occidentalis) that feed on a wide range of plants and others that feed on a more limited number of plant species. They're far smaller than an aphid, for example and don't look like beetles. In fact unless one looks very closely one isn't very likely to even see them. Hopefully Steve will clarify.
Edited to add, speaking of size comparison, I just remembered I took a picture some time ago of a thrips and an aphid to show how tiny a thrips is: