Sierra Natural Science SNS 209 supplies plants with a small amount of rosemeric acid, distributing it throughout cell walls. When an insect starts to suck or chew on the plant and contacts the rosemeric acid, it stops eating and moves on. SNS-209 Systemic Insect Control is made up of 100% pure botanical extracts that are highly water soluble. The botanical extracts are all food-grade GRAS (generally recognized as safe) materials.