They appear overnight and do much damage........
On most evenings I water my tomato plants and look carefully around the pots for "the sign"
The sign is easily spotted unlike the worm....I skipped one evening and darn if that wasn't the night they devoured the tops of my plants. They go for the newest leaves and can strip a plant in no time! They blend with the leaves and stems and are very hard to see. If you do find one, keep searching, there will be more.
I am baffled at where these critters come from?