It is as if I have sand fleas in my beans, and they are biting when I pick the crop. It was so annoying to be scratching my legs every two seconds! They are very tiny black hopping things that live in the plant and the grass nearby. They are only there when it is not wet - I haven't seen them at all in the early morning but they are there in the afternoon and evening. I've read that catnip or mint might help keep flea like creatures away, but is there anything not perennial that you can think of?