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CTA. 1996. Fatal flowers. Spore 63. CTA, Wageningen, The Netherlands.
Permanent link to this item: http://hdl.handle.net/10568/47331
Compounds found in chrysanthemum daisies have been successfully exploited commercially for many years as pyrethrin insecticides. Now researchers have found, high in the Andes, another plant which they hope will have the same potential. The delicate...
Compounds found in chrysanthemum daisies have been successfully exploited commercially for many years as pyrethrin insecticides. Now researchers have found, high in the Andes, another plant which they hope will have the same potential. The delicate yellow-flowering plant, Calceolaria andina, contains two chemicals that kill sapsucking insects such as aphids and white fly, including those which have become resistant to most modern insecticides. The two compounds, called naphthoquinones, have even killed the notorious pesticideresistant 'B-biotype' strain of the tobacco white fly, Bemiria tabaci. Although the name suggests that it is a particular pest of tobacco, the Bbiotype attacks some 600 species of plants worldwide, multiplying five times faster than other strains of B. tabaci, and is capable of transmitting up to 60 viruses to their host plants. The naphthoquinones have also proved fatal to other sucking pests that have grown resistant to pesticides, including the spotted spider mite, Tetranychus urticae, an d the peach potato aphid, Myzus persicae. Extracts from over 400 plant species collected from the Chilean Andes were sent to the University of Southampton's Agrochemical Evaluation Unit in the UK. The team at Southampton passed on the 20 most promising extracts for further analysis to the Institute of Arable Crops Research at Harpenden in Hertfordshire. Researchers there took just one week to isolate the naphthoquinones which were easy to extract, accounted for 5% of the dry matter of the plant and proved to be the most active components in extracts of Calceolaria. This research, which is supported by British Technoloy Group plc, has considerable commercial potential, and owes much to lACRRothamsted's expertise in natural products chemistry and pesticide resistance. Work continues at lACR-Rothamsted to develop the effective use of these new bioactive compounds in integrated pest management strategies. Dr B Khambay IACR Rothamsted, Horpender Herts AL5 2JQ. UK