1. International Centre of Insect Physiology and Ecology (icipe), P.O Box 30772-00100, Nairobi, Kenya; 2CIRAD UPR HORTSYS, 34398 Montpelier Cedex 5, France; 3UPR HORTSYS, University of Montpellier, 34398 Montpellier, France; 4Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA; 5Rutgers University, 59 Dudley Road New Brunswick, New Jersey 08901, USA; 6Department of Agricultural Economics, University of Nairobi, P.O Box 29053, Nairobi, Kenya.