ORIGINAL CONTRIBUTION Suitability of cereal stemborers in Cameroon to Kenyan populations of the braconid larval parasitoid Cotesia sesamiae R. Ndemah 1 , F. Schulthess 2 , A. Abang 3 , R. T. Ghogomu 3 , N. Ntonifor 4 , S. Dupas 5 & B. LeRu ¨ 5 1 International Institut of Tropical Agriculture, Yaounde ´ , Cameroon 2 Postfach 508-4, Chur, Switzerland 3 Faculte ´ Agronomique et de Sciences Agricoles, Universite ´ de Dschang, Dschang, Cameroon 4 Faculty of Science, University of Buea 5 UR 072, c/o CNRS, Laboratoire Evolution, Ge ´ nomes et Spe ´ ciation, Gif-sur-Yvette Cedex; and Universite ´ Paris-Sud 11, Orsay Cedex, France Introduction In Cameroon, Busseola fusca (Fuller) (Lep.: Noctuidae) is the most important maize pest across all agroecological zones except for the humid coastal forest, where Sesamia calamistis Hampson (Lep.: Noctuidae) is the predominant species (Ndemah et al. 2007). Yield losses due to B. fusca range from 25% to 55% (Cardwell et al. 1997; Ndemah and Schulthess 2002; Chabi-Olaye et al. 2005a). Several control techniques, among them insecticides (Ndemah and Schulthess 2002), habitat management technologies (Ndemah et al. 2002, 2006; Chabi-Olaye et al. 2005a), and management of soil fertility (Chabi-Olaye et al. 2005b, 2006, 2008) have been tested in the humid forest (HF) zone of Cameroon. They reduce yield losses by up to 90% but none of them provides a sustainable solution and they all require changes in farmers’ practices. Biological control, if working, is self- sustainable and compatible with the other control options developed. Keywords Busseola fusca, Cotesia sesamiae, Poeonoma serrata, Sesamia cretica, larval parasitoid, suitability Correspondence Fritz Schulthess (corresponding author), Postfach 508-4, 7004 Chur, Switzerland. E-mail: fritz.schulthess@googlemail.com Received: July 7, 2010; accepted: September 16, 2010. doi: 10.1111/j.1439-0418.2010.01585.x Abstract The noctuid Busseola fusca is the most destructive pest of maize in Cameroon. Various habitat management technologies have been developed and tested but none of them provides a self-sustainable solution. The braconid Cotesia sesamiae, the most common larval endoparasitoid of the B. fusca in eastern Africa, is rare in West Africa and Cameroon. In Cameroon, it is mostly found on non-crop borer species feeding on wild grasses. Thus, two Kenyan C. sesamiae populations and their hybrid were introduced into Cameroon. Suitability studies were carried out with two B. fusca populations, the noctuid Poeonoma serrata, which is commonly found feeding on Napier grass but not maize, and the noctuid Sesamiae cretica, which was recently accidentally introduced into Mauritania, where it attacks sorghum. The performance of the C. sesamiae was influenced by both host species/ population and parasitoid population, although the B. fusca population had a minor effect. The reproductive potential of the hybrid was superior over that of its parent populations. The least suitable host was P. serrata, thus it was concluded that it would probably not play a major role in perennating C. sesamiae during the dry season. With S. cretica as host, parasitism was similar but brood size was lower than with either B. fusca population. Release strategies of C. sesamiae and its chances of establishment on B. fusca and S. cretica in the hot–humid forest zone and the cool highland of Cameroon and in Mauritania are discussed. J. Appl. Entomol. 60 J. Appl. Entomol. 136 (2012) 60–69 ª 2010 Blackwell Verlag, GmbH