Neem oil, every outdoor grower should be using this. Its totally safe for humans, so it doesnt affect your smoke. Best thing since sliced bread, seriously.
Spray it on the plant, make sure you get the bottoms of the leaves. Make sure you dont get any in your eyes. It stings.
Lowes has a brand called "GreenLight". You can also get it at hydro stores, I use "Einstein Oil" and it works great but it can be expensive.