The Wx/Block formula, that glider pilots have using for years, is based on a Teflon-like polymer and has been noted to be effective in this regard. We've run tests with several coats on one leading edge and none on the other wing and there is a noticeable difference in the number of bug "sticks".

First commercial aircraft guys realized our winglets were a good idea... next thing they'll take credit for inventing bug wipers ;-)

Bob