Cabbage Worm (Pieris rapae) on kale.
The leaves of my kale and broccoli are disappearing. I thought that they were being eaten by some earwigs but upon close inspection I saw a multitude of velvety green larvae that are camouflaged on the leaves. These are the larvae of the adult moth Pieris rapae.
Pieris rapae is a beautiful small-sized butterfly known as the Cabbage White butterfly. If you see a dainty-looking white butterfly with black dots on the wings flying around your garden, be extra observant. While the adult is harmless, the larvae (commonly known as Cabbage-worm) are voracious and they feed on most brassica crops. At the early stages of the larvae, the damage happens slowly but once they reach a substantial size, they can defoliate the plants quickly.
There are a number of effective and safe biological control for the cabbage worm. Basillus thuringiensis (Bt) and spinosad. Ask your local nursery for these active ingredients and they will lead you to the right products. These are both biological and considered organic pesticides.
As for me, since I do not have a huge garden, I prefer to do it by hand - picking the worms every morning. This is also biological and organic method, mind you. :) But this requires that I have to be vigilant.
Stroll in your garden, and squash all the cabbage-worms you see :)