Fenvalerate

Fenvalerate is a synthetic pyrethroid insecticide belonging to the Type II class, characterized by the presence of an alpha-cyano group. It is used to control a broad range of agricultural and horticultural pests on crops, ornamentals, and in some public health settings. Commercial formulations include emulsifiable concentrates, wettable powders, granules, and ready-to-use liquids.

Mode of action and effects: Fenvalerate acts on the nervous system of insects by altering the function of voltage-gated sodium channels, delaying repolarization and prolonging nerve impulses. This neurotoxic action leads to rapid onset of tremors, incoordination, paralysis, and death in susceptible pests. Type II pyrethroids, such as fenvalerate, often produce more pronounced paralytic symptoms than Type I compounds.

Applications and spectrum: It provides control of caterpillars, beetles, aphids, leafhoppers, mites, and some other pests in crops including fruits, vegetables, grains, and ornamentals. It is typically applied as a protective spray, drench, or granule, and may be used in combination with other pesticides in integrated pest management programs.

Environmental and safety considerations: Fenvalerate is highly toxic to aquatic organisms and non-target insects; exposure to humans and animals can cause neurological symptoms at high doses, though acute mammalian toxicity is relatively low with proper handling. It degrades in the environment by photolysis and microbial action; residues are regulated by authority-specific tolerances. Workers should follow label directions and use appropriate protective equipment.

Regulatory status and resistance: Regulatory status varies by country, with some jurisdictions imposing restrictions or bans on certain uses due to environmental and non-target risks. Insects can develop resistance to fenvalerate, necessitating rotation with other modes of action and adherence to integrated pest management practices.