This is a common expression to describe the larval stage of Lepidoptera. But they are only "worms" in the sense of their Proto Indo-European word origin meaning to "to twist" of "turn", snake or dragon like. Anyway, they aren't earthworms and they don't even taste like earthworms.
Anyway, with the changing weather, there have been more reports of Lepidopteran larvae than I normally hear about. Different weather, a bit warmer, wetter, more green growth out there. New leaf flush coming on. Keep your eyes open for some of these insects feeding on leaves and possibly turning to feed on fruit at some point. Where you see avocado fruit clusters, it's quite likely that this stage will like to hide there to eat and pupate, so look for the webbing.
Last year was definitely a spider year. 
They were swinging from the trees and entangling visitors in their webbing that crossed alleyways and somehow scrambled on to car mirrors and other zones where they might trap food. They were feeding on something, and some of that was our night flying moths. This year might see another spider year, if we start building a population of leps this spring.
So keep your eyes peeled for Lepidopteran larvae (plural, larva is singular). Here's some help identifying them. Along with the images here, there are some links to IPM websites that have more information on the biology and care of these "worms".
https://ipm.ucanr.edu/agriculture/citrus/ , https://ipm.ucanr.edu/PMG/GARDEN/FRUIT/PESTS/leafroller.html
https://ipm.ucanr.edu/PMG/C008/m008bpcaterpillars.html
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