Neonicotinoids are a relatively new type of insecticide, used in the last 20 years to control a variety of pests, especially sap-feeding insects, such as aphids on cereals, and root-feeding grubs.
Neonics are systemic pesticides. Unlike contact pesticides, which remain on the surface of the treated foliage, systemics are taken up by the plant and transported to all the tissues (leaves, flowers, roots and stems, as well as pollen and nectar). Products containing neonics can be applied at the root (as seed coating or soil drench) or sprayed onto crop foliage. The insecticide toxin remains active in the plant for many weeks, protecting the crop season-long.