Sevin liquid concentrate is made from carbaryl, a broad-spectrum insecticide designed for use on vegetables, fruits, small trees, flowers and shrubs. Carbaryl kills insects by disrupting their nervous systems. It’s effective on more than 100 different types of pests and is one of the most commonly used pesticides in the United States. Mixing and application rates vary depending on the type of plant that requires treatment. It’s best to apply liquid Sevin on days with calm winds and when no rain is expected for at least 24 hours.