Unexpected developments from the SEMIOCHEM LINK Programme
The production of semiochemicals, in particular a highly active nepetalactone isomer from cultivation of the catmint Nepeta cataria as a non-food crop, has yielded material for commercial development and for further, more extensive, field trials. The major target is aphid control (the nepetalactone being a highly active aphid sex pheromone component), but its main use is in manipulating aphid parasitoids, for example in the SAPPIO programme, "3D Farming - Making biodiversity work for the farmer", run by Professor Wilf Powell of IACR-Rothamsted. However, a new use for these compounds has recently been identified in collaboration with a number of research groups worldwide, including Professor Jim Hardie's group at Imperial College, Silwood Park, Professor Kyung Saeng Boo's group from Seoul, Korea, and Professor Neil Holliday's group at the University of Manitoba, Winnipeg, Canada.
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Actinidia polygama, which provided the
idea for molecular modification of the nepetalactone for lacewing attraction. © IACR-Rothamsted |
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Peyerimhoffina gracilis, not known in
the UK until caught by means of the new lacewing attractants. © R.H.J. Verkerk, Imperial College, Silwood Park |
During trials in Korea and Canada, it was found that a nepetalactol derived from one of the nepetalactone isomers attracted another group of insects antagonistic to pest aphids, the lacewings. Some evidence for lacewing attraction, though initially less impressive than in Korea, was then observed at Silwood. This raised the opportunity of looking at chemical modification of the nepetalactone, now readily available from farming and extraction (i.e. by the LINK partner, Botanix Ltd., under Dr. Ray Marriott), to see if more active compounds could be generated for lacewing attraction. Following early reports from Japan that highly reduced nepetalactones, i.e. dihydronepetalactols, found in the vine Actinidia polygama, attracted Far Eastern species of lacewings, we began to produce the various isomers of these compounds. One of these we believe to be identical to a compound named by the early Japanese workers as neomatatabiol, named after Matatabe, the Japanese common name for A. polygama. As this compound proved to be highly active in attracting lacewings, not only in Korea but also at Silwood Park, we characterised it fully using sophisticated NMR spectroscopy at Rothamsted and X-ray crystallography with Dr. Rowena Paul at the University of Bristol.
Two further exciting developments followed. It was found that the lacewings attracted were almost exclusively males, suggesting some kind of sex pheromonal role. In addition, a species of lacewing completely new to the United Kingdom was discovered. This species was identified, with the help of Dr. Stephen Brooks at the Natural History Museum, as Peyerimhoffina gracilis, which presumably had only recently colonised Britain through climate change, and which certainly would not have been noticed without the use of these plant-derived attractants. Although the females and their larvae are the most valuable as predators, this type of attractant might offer a means of aggregating both sexes.
This further movement into increasing the efficacy of biological control systems against insect pests is fortuitously coincident with a commercial development. AgriSense BCS Ltd, which is a partner in the Semiochemical LINK programme, was recently acquired by Certis International, the agrochemical arm of Mitsui & Co. of Japan. Biological Crop Protection Ltd, another Mitsui affiliate, produces beneficial insects and mites for biological control of greenhouse pests. Dr. Owen Jones, the chairman of AgriSense BCS, believes this provides an excellent opportunity for both companies now to explore together the opportunities that arise from combining semiochemicals with predator and parasitoid use for insect pest control.
Contact
John A. Pickett, IACR-Rothamsted, Harpenden, Herts, AL5 2JQ.
Tel: 01582 763133 x2321 Fax: 01582 762595
E-mail: john.pickett@bbsrc.ac.uk
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Page last modified: 20 Jun 2002