Also keep in mind whole flower heads stay potent longer so do not grind until ready to use. Spray both the upper and lower surfaces of the leaves, because spray must directly contact the insects such as thrips that hide in leaf sheaths and crevices. The first spray will excite them and bring them out of hiding, the second will kill them. Never use pyrethrin products around waterways and ponds. Nicotine One of the top three insecticides in the 1880s, nicotine in several forms is still widely used.
Nicotine comes from the tobacco plant and is extremely toxic to insects.
The great advantage of home-made nicotine tea is that it is very short ived, retaining its toxicity for only a few hours after spraying. It is relatively nonhazardous to bees and lady beetles because of its short persistence. The solution will keep for several weeks if stored in a tightly closed container. Nicotine can be absorbed by plant leaves and remain there for several weeks. It's probably safest not to spray nicotine on eggplant, peppers or tomatoes.