If pesky insects are causing problems with your plants, now's the time to develop an integrated pest management strategy. For large insects like caterpillars, a good first line of defense is to remove them by hand.
Put on a pair of gloves, pull the insects off the plants, and drop them in a container of soapy water. The soap breaks the surface tension, so the insects will sink to the bottom and drown.
If you feel squeamish about handling insects, ask a child to help. Kids are naturals at catching insects! Remind them to wear gloves and check the undersides of leaves, since pests often hide there.
Hand-picking insects is a great integrated pest management strategy because it causes zero harm to you or the environment. And it won't cost you a penny.