Scientists link in hunt for natural pesticide

SCIENTISTS at the Royal Botanic Gardens at Kew, south- west London, have linked with other research centres in a multi- million pound pesticides business, writes Susan Watts. The venture aims to unlock the defences that plants use to ward off predators naturally. Scientists believe that nature's own toxins could form effective biological alternatives to chemical pesticides.

The search is urgent as more and more insects develop resistance to chemical treatments, and the rewards could be high. Biological pesticides make up less than 2 per cent of the pounds 7.4bn pesticide market, but this is expected to rise to 50 per cent by the turn of the century.

Kew is pooling its resources with the laboratories of the Agricultural and Food Research Council, at Rothamsted, Hertfordshire. The two are also linking up with the British Technology Group.

The technology group built its business on a group of pesticides known as pyrethroids. The active part of these was spotted, by a Rothamsted team, in crysanthemums. The new project hopes to repeat such discoveries. 'We are using plants as chemists,' Monique Simmonds, head of biological interactions at Kew, said.

A compound with tremendous potential was found in the leaves and nuts of Lonchocarpus costa ricensis, a Costa Rican tree. It will kill nematodes - worms that account for hundreds of millions of pounds worth of pesticides a year, particularly on bananas and citrus fruit.

(Photograph omitted)