Yep, about 1/2tsp. dish soap, or even liquid hand soap works fine, to a quart of water in a spray bottle.
I asked the entemologist at our Extension office, Dr. Santana, about the soap vs. detergent question a couple of years ago and he says it doesn't matter. They both cut through the waxy coating on the insects' bodies and cause them to dehydrate and die. It's such a mild solution that as long as you have something that dissolves that wax it will work. Use whatever liquid dish soap you have.
Interesting, though, in this article it says soap will leave a scum when used with hard water, while detergent won't. Still we use so little, it probably won't affect the plant.
http://www.ask.com/question/wh...
Just don't spray any soapy solution when the sun is going to be on the leaves. I burned a brug pretty badly one time doing that!
Glad you caught the caterpillar, keep an eye out. Some of the ones I caught were over an inch long, they can do some serious damage in one night!
