Demand-Driven Technologies for Sustainable Maize ... - IITA

318Table 1. Relative abundance and species diversity of maize stem and cobborers on maize variety CMS 9015 intercropped with cowpea.Locality Treatment B. f.* S. c. E.s. M.n. H’Maize treated with insecticide 98.5 0.0 0 0.5 0.06Nyom II Maize-cowpea intercrop 96.5 3.5 0 0.0 0.21Control 96.0 4.0 0 0.0 0.25Maize treated with insecticide 96.5 2.5 0 0.0 0.14Bafi a Maize-cowpea intercrop 96.5 2.5 1 0.0 0.19Control 89.0 10.0 1 0.0 0.48*B.f.=Busseola fusca; S.c.=Sesamia calamistis; E.s.=Eldana saccharina; M.n.=Mussidianigrivenella; H’=Shannon-Weiner’s diversity index. Values in the table are means of 2cropping seasons (1999 and 2000 second cropping seasons).information content of sample bits/individual), Pi is the proportion oftotal sample belonging to one species (i.e. total number of individualsof one species/total number of individuals) (Peet 1974).ResultsRelative abundance and diversity of maize borersB. fusca, S. calamistis, E. saccharina and M. nigrivenella were the stemand cob borer species collected during this study (Table 1). The fi rsttwo species were present nearly in all treatments at Nyom II, while M.nigrivenella was absent in Bafi a. On the other hand, S. calamistis wasnot found on maize treated with Carbofuran in Nyom II, but a fewmoths of M. nigrivenella were found. Borer species recorded in Bafi awere present in the three treatments, except E. saccharina, which wasabsent in maize treated with Carbofuran. Species diversity indexeswere low in treated maize plots and much higher in the untreatedcontrol plots at both locations.Abundance of stem borer speciesResults presented in Table 2 showed that the total number of stemand cob borer larvae of all stages and pupae collected in Nyom II werehigher than in Bafi a (1752 vs 324). Furthermore, the total number ofborers in untreated plots was signifi cantly higher than those from theother plots regardless of the location. B. fusca was the most abundantspecies in all the treatments. Eldana saccharina was absent in Nyom IIwhile M. nigrivenella population was very small.Maize borer infestationThe level of infestation of maize by stem and cob borers was signifi cantlylow on treated plots in all locations and planting dates (Table 3). Inaddition, the percentage of plants infested was lower in intercroppedthan monocropped maize, although a signifi cant difference could befound only in the second date in Nyom II. The fi rst planting date, which