A trick I do too help keep bugs away is keep a cup full of moth balls with a lid on it from a restaurant of somewhere. Poke a hundred holes in the styrofoam cup, fill it halfway with moth balls, put the lid on and keep em by your plant. The moth balls don't get lost or get wet and lose there smell and it keeps all the critters away.
I spread mothballs around my deck to keep the stray animals away and they work real well....never thought about using them by the plants...Great idea!.