The oil of the Neem (Azadirachta indica) tree is a natural insecticide heavily favored by organic gardeners all over the world. 

We decided to make an insecticide out of the leaves. Here’s a recipe:

1) Gather about 2 pounds of fresh Neem leaves
2) Cover in water allowing at least 2-3 inches of water above the leaves
3) Soak leaves for seven days, remembering to keep this brew in a place where the smell will not be offending (it will stink)
4) On the eighth day, strain the leaves from the water while through cheese cloth. The liquid should be clear.
5) Shake well as you use.