Imidacloprid is an insecticide that was made to mimic nicotine. Nicotine is naturally found in many plants, including tobacco, and is toxic to insects. Imidacloprid is used to control sucking insects, termites, some soil insects, and fleas on pets. It has been used in products sold in the United States since 1994.
Imidacloprid disrupts the nerve's ability to send a normal signal, and the nervous system stops working the way it should. Imidacloprid is much more toxic to insects and other invertebrates than it is to mammals and birds because it binds better to the receptors of insect nerve cells.
Imidacloprid is a systemic insecticide, which means that plants take it up from the soil or through the leaves and it spreads throughout the plant's stems, leaves, fruit, and flowers. Insects that chew or suck on the treated plants end up eating the imidacloprid as well. Once the insects eat the imidacloprid, it damages their nervous system and they eventually die.