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Pheromone from the summer cypress Killed Mosquitoes (West Nile virus) in trials Everytime

*Reposted at Request, data known since 1999….  The government will not justify the expense in regards to human life and the environment…Engineering Evil

Contact: Claire Bowles claire.bowles@rbi.co.uk 44-171-331-2751 New Scientist

A burning bush could smite New York’s mosquitoes

An ornamental bush prized by gardeners in Europe and the US contains a surprise weapon against the mosquitoes spreading West Nile virus, the brain disease that has broken out in New York (p 13). The bush might also provide a cheap way for the world’s poorest countries to fight filariasis, a disfiguring parasitic disease that affects 15 million people in Africa alone.

Oil from the summer cypress, better known as the burning bush because it blushes a deep red in autumn, contains a substance which, when converted into a pheromone, can be used to lure mosquitoes to their deaths.

New Yorkers could have used this trick to combat the mosquitoes spreading the West Nile virus. The virus attacks the central nervous system and 3 of the 12 people with the illness have already died. Another 102 suspectedcases are being investigated. New York health officials are fighting the outbreak by killing mosquitoes with conventional sprays of the powerful insecticides malathion and pyrethroid.

Burning bush oil might have provided a more benign solution. Researchers from Britain and Nigeria have turned oil from the plant’s seeds into a pheromone. This biological messenger, which is odourless to humans, could lure female mosquitoes away from the places where people live.

A team from the Rothamsted site of the Institute of Arable Crops Research in Harpenden, Hertfordshire, struck lucky when team leader John Pickett noticed that the burning bush makes a fatty acid strikingly similar to the pheromone that attracts the mosquitoes (Journal of Agricultural Food Chemistry, vol 47, p 3411).

The pheromone is produced naturally when rafts of eggs are laid in stagnant water by Culex quinquefasciatus, the mosquito species which spreads filariasis and is suspected of spreading West Nile virus. “It’s a cue for female mosquitoes, telling them that there’s a safe place where they can lay their eggs,” says Mike Birkett, a member of the Rothamsted team.

The pheromone from the burning bush could have been used in New York to lure mosquitoes to their death in drums of water laced with pesticide, says Birkett. Pickett is confident that the pheromone attracts females of all Culex species.

The team at Rothamsted has tested synthetic versions of the same pheromone, called (5R,6S)-6-acetoxy-5-hexadecanolide. “It’s been tested in field trials in Africa, Japan and the US, and it works every time,” says Birkett. The problem is that the synthetic version is too expensive to manufacture. So instead, the team screened plants for substances which could be turned into the pheromone much more cheaply.

It doesn’t need to be purified from the oil, making it cheap and easy to handle. When Jenny Mordue of the University of Aberdeen tested the oil-based pheromone in the laboratory, she found that it attracted female mosquitoes as powerfully as the natural substance.

###Author: Andy Coghlan

Issue 2nd October 99

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