Is there a simple way to test if pesticides are on something (anything)?

Answer 1

A simple way? Not really. If they're present they are usually in trace amounts that would require laboratory analysis.

Depending on the pesticide sometimes you can taste or smell them. I'm not saying you should rely on your taste buds or nose.

Answer 2

Take a leaf or branch to your local Extension office and they can send it off to the lab and have it checked for a small fee.