imidacloprid

Imidacloprid is a neonicotinoid insecticide developed by Bayer CropScience and introduced commercially in the 1990s. It is a systemic compound, absorbed by plant roots or foliage and distributed through the xylem, providing protection against a wide range of insect pests over an extended period.

Mechanism of action is as a nicotinic acetylcholine receptor agonist in the insect nervous system. This causes overstimulation, leading to paralysis and death. The systemic nature makes imidacloprid effective against many sap-sucking pests such as aphids, whiteflies, and scale insects, and it is also used against some soil-dwelling and chewing pests depending on the formulation and crop.

Applications and formulations vary. Imidacloprid is marketed as seed treatments, soil drenches, foliar sprays, granular formulations, and trunk injections. It is used on a broad array of crops, including grains, sugar beets, canola, soybeans, fruits, vegetables, and ornamental plants.

Environmental and safety considerations are central to its use. Imidacloprid is toxic to non-target insects, particularly bees, and to aquatic invertebrates. It can persist in soil for weeks to months and may leach under certain conditions, raising concerns about pollinator exposure and water quality. To mitigate risks, label-directed timing, rates, and application methods are essential, along with adherence to integrated pest management practices.

Regulatory status varies by country and over time. In the European Union, outdoor uses of several neonicotinoids, including imidacloprid, have been restricted due to pollinator concerns. Other regions maintain approvals with risk assessments and usage restrictions, with ongoing evaluations guiding usage and potential restrictions.