SNS 209 Systemic Pest Control - Concentrate Safely & Easily Make Your Plants Resistant To Pests! SNS-209™ All Natural Systemic Pest Control Concentrate provides a barrier for plants to protect them against damaging insects. How it Works: Spider mites, White flies, Nematodes, Scales and other insects destroy plant cells by sucking out their fluids or chewing up the cell walls. SNS-209™’s unique formula works by allowing the plant to uptake a small amount of rosemeric acid from the rosemary plant. As the plant distributes the rosemeric acid throughout its cell walls, a barrier is soon constructed. When an insect starts to suck or chew on the plant, it comes in contact with the rosemeric acid and causes the insect to stop eating, move on or die.