Rediscovered: a safer insecticide

Silicon dioxide is a naturally occurring substance which can kill a variety of insects by attacking their waterproof waxy cuticle, leading to dehydration. It has been particularly effective against cockroaches, and is known to be effective against many beetles, weevils, moths and lice. Its toxic effects are so negligible that silicon dioxide is permitted for use as a food additive.
    The compound has been approved by the UK Health and Safety Executive as a public hygiene insecticide for use against cockroaches(1), and further uses are being investigated. Interestingly silicon dioxide was used in the UK as an insecticide before pesticides were regulated in 1986, but approval is only now being sought under the new regulations. It has remained available in the US and is recommended for use as a non-toxic insecticide against ants, aphids, beetles, bees, bugs, cockroaches, crickets, fleas, food pests, silverfish, termites and ticks(2). 
    Approval in the UK is held by Rentokil which plans to use it in their own pest control operations from this autumn. The powder will be placed in areas which cockroaches pass through. Rentokil does not plan to seek approval for uses other than cockroach control at present. It will not be available as a commercial product to other professional pest control operators or to the public.

1. Advisory Committee on Pesticides Amorphous silicon dioxide use as a public hygiene insecticide, Evaluation No. 129, HSE, April 1995.
2. Olkowski, Daar, Olkowski, Common sense pest control, The Taunton Press, 1991.