Based on a paper presented at the symposium ‘The Economic and Commercial Impact of Integrated Crop Management’, organised by the SCI Crop Protection Group in collaboration with the Volcani Center, Israel and the Fresh Produce Consortium and held on 3–4 April 2000 at 14/15 Belgrave Square, London SW1X 8PS, UK
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Research Article
Exploiting chemical ecology and species diversity: stem borer and striga control for maize and sorghum in Africa†
Article first published online: 13 OCT 2000
DOI: 10.1002/1526-4998(200011)56:11<957::AID-PS236>3.0.CO;2-T
Copyright © 2000 Society of Chemical Industry
Issue
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Pest Management Science
Special Issue: Integrated Crop Management
Volume 56, Issue 11, pages 957–962, November 2000
Additional Information
How to Cite
Khan, Z. R., Pickett, J. A., Berg, J. v. d., Wadhams, L. J. and Woodcock, C. M. (2000), Exploiting chemical ecology and species diversity: stem borer and striga control for maize and sorghum in Africa. Pest. Manag. Sci., 56: 957–962. doi: 10.1002/1526-4998(200011)56:11<957::AID-PS236>3.0.CO;2-T
- †
Publication History
- Issue published online: 13 OCT 2000
- Article first published online: 13 OCT 2000
- Manuscript Accepted: 30 JUN 2000
- Manuscript Revised: 17 JUN 2000
- Manuscript Received: 2 JUN 2000
Funded by
- UK Biotechnology and Biological Sciences Research Council
- Gatsby Charitable Foundation
- Rockerfeller Foundation
- Abstract
- Article
- References
- Cited By
Keywords:
- stem borers;
- striga;
- push-pull;
- trap crop;
- intercrop;
- attractant;
- repellent;
- semiochemical
Abstract
Stem borers, comprising the larvae of a group of lepidopterous insects, and parasitic witchweeds, particularly Striga hermonthica and S asiatica, cause major yield losses in subsistence cereal production throughout sub-Saharan Africa. Studies are described that have led to the development of a ‘push-pull’ strategy for minimising stem borer damage to maize and sorghum. This involved the selection of plant species that could be employed as trap crops to attract colonisation away from the cereal plants, or as intercrops to repel the pests. The two most successful trap crop plants were Napier grass, Pennisetum purpureum, and Sudan grass, Sorghum sudanensis. The intercrop giving maximum repellent effect was molasses grass, Melinis minutiflora, but two legume species, silverleaf, Desmodium uncinatum, and greenleaf, D intortum, gave good results and had the added advantage of suppressing development of S hermonthica. In terms of stem borer control, the plant chemistry responsible involves release of attractant semiochemicals from the trap plants and repellent semiochemicals from the intercrops. With M minutiflora, parasitism of stem borers was also increased by certain chemicals repellent to ovipositing adults. The mechanism of striga control has not been fully elucidated, but allelopathic effects from the Desmodium species have been shown to involve stimulation of germination and interference with haustorial development. Significant beneficial effects have been obtained with the individual components of these push-pull strategies. However, the most robust crop-protection package is obtained when these components are combined. The trap crop and intercrop plants also provide valuable forage for cattle, often reared in association with subsistence cereal production. There has been considerable take-up of the system within the communities where farmer-managed trials have been carried out, particularly in the Trans Nzoia and Suba districts of Kenya, and the programme is set to expand throughout and beyond Kenya.
© 2000 Society of Chemical Industry