Have you found holes in your plants...seedlings cut down... leaves cut off at the base...black pellets on the leaves and at the base of the plant...?

You look all over the plant in broad daylight...the pot...the soil...the ground...and yet you find nothing and no sign of life?

This is most likely your culprit.

"The Cabbage Looper" - Trichoplusia ni

It's a green "inchworm" which feeds on an absolutely huge variety of plants, including tomatos, corn, herbs, lettuce and cabbage, radishes, and even the Ti plants.

Next time you get the chance, take a late night stroll through the garden with a flashlight, preferabbly an L.E.D. as they stand out more with this type of light source, and check out your plants. Watch the plants for any movement, or look close at the stalks and underside of the leaves for a bright green worm, anywhere from 1/8 - 1.5 inch in length.
Examine photos of this species closely and it will make the real thing stand out MUCH better, promise!

They have been found to adapt to various insecticidal soaps and poisons, so try different methods and find what works for you. Remember, always try the least destructive and least expensive method before you move onto something bigger. Sometimes even the simplest action lik moving them to a Ti plant away from your garden... will do nearly the same thing as mass-destruction and biological warfare, with alot less effort...and no effect on other aspects of the garden!

Hope this helps even one of you out, sorry it took me THIS long to find the little buggers information, but I recently had a few other posts and friends reaffirm my suspicions!

Aloha for now,
~Dave