Simagchem Corp.

Uses The four neonicotinoids are acetamiprid (l),imidacloprid (2), nitenpyram (3) and thiamethoxam (4) (IS0 draft proposal name). They are potent broad spectrum insecticides possessing contact, stomach and systemic activity. The structures are given below and consist of substituted aromatic heterocyclic rings: 6-chloropyridinyl for acetamiprid, imidacloprid and nitenpyram and 3-chlorothiazole for thiamethoxam. Each compound has a methylene bridge, to a cyclic nitroguanidine moiety in imidacloprid and thiamethoxam, to a cyanoamidine in acetamiprid or to a diaminonitroethylene group in nitenpyram. The terminal group for all compounds is a strong electron-withdrawing substituent on an ethene or imino group.

These insecticides are used for foliar and soil application but imidacloprid also has a very high usage as a seed treatment. They have low rates of application: for example thiamethoxam is typically applied to foliage at rates of only 2.5-50 g ha-1. The neonicotinoids are polar, nonvolatile solids with high water solubilities and they are non-ionised at pH values typically found in the environment. The insecticides are not readily hydrolysed. Their polar nature makes them potentially mobile in soil but this is mitigated by their low rates of application and, for acetamiprid and nitenpyram, short persistence. hnidacloprid and thiamethoxam are sufficiently persistent to be used as soil treaments. All the insecticides are efficiently translocated in plants and are effective systemic agents against sucking pests.