It's also one of the most toxic to warm-blooded animals and it's readily absorbed through the skin. It breaks down quickly, however, so it is legally acceptable to use on organically grown crops. Nicotine sulfate is sold as a 40 percent nicotine sulfate concentrate under trade names that include Black Leaf 40 or Tender Leaf Plant Insect spray. Nicotine kills insects by interfering with the transmitter substance between nerves and muscles. It's commonly used to control aphids, thrips, spider mites and other sucking insecticides on most vegetables, some fruits, flowering plants and ornamental shrubs and trees.
Roses are sensitive to nicotine.
Choose alternate pest control measures when treating insects on roses. Sabadilla Sabadilla, another botanical insecticide, is derived from the seeds of the sabadilla lily. The active ingredient is an alkaloid known as veratrine. Sabadilla is considered among the least toxic of botanical insecticides, but its dust can be highly irritating to the eyes and can produce sneezing if inhaled. No residue is left after application of sabadilla because it breaks down rapidly in the sunlight.