1. Département de Formation en Protection des Végétaux, B.P. 12625, Niamey, Niger
2. International Institute of Biological Control, Silwood Park, Buckhurst Road, Ascot, Berkshire SL5 7TA, UK
3. Plant Health Management Division, International Institute of Tropical Agriculture, B.P. 08–0932, Cotonou, Benin
4. Leverhulme Unit for Population Biology and Biological Control, Natural Environment Research Council Centre for Population Biology, Imperial College, SilWood Park, Ascot, Berkshire SL5 7PY, UK ()