Cut the leg off of a pair of old panty hose to make a shaker bag. Pour self rising flour in the sock part and tie off the open end.
Only self rising flour will work. I presume it may be the baking powder that is in self rising flour? .
Shake the self rising flour sock to dust all the leafy vegetables. The self rising flour on the plants will cause all the leaf eating worms to swell up and burst open.
The plants have to be re-dusted after a rain washes it off.
This is the least toxic method to rid leaf eating worms.