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

320Table 4. Maize stem borers’ stem tunneling and corresponding yieldon maize intercropped with cowpea in comparison with maizetreated with Carbofuran.LocalityTreatmentParameters measuredTunneling, % Yield, t ha -1MbangassinaMaize treated with insecticideMaize-cowpea intercropControl12.5a*28.0b2.1a1.8aNkolndaMaize treated with insecticideMaize-cowpea intercropControl42.3c17.6a39.0ba1.8a2.9a2.6aMinkoameyosMaize treated with insecticideMaize-cowpea intercropControl54.1c3.7a5.7a2.8a1.9a2.2a7.8a1.7a*Means followed by the same letter within a column are not signifi cantly different at the0.05 level of probability.The percentage of tunnels due to stem borers followed the sametrend as the level of infestation. The proportion of stems tunneled wassignifi cantly lower in plots treated with Carbofuran than in intercroppedand untreated plots (Tables 3 and 4).The low level of infestation and low percentage of tunnels ontreated maize indicate the effi cacy of Carbofuran on stem borercontrol. The insecticide was applied six weeks after planting. At thisstage the majority of larvae (especially B. fusca) were still in the whorlwhere granules of Carbofuran were applied.A signifi cant difference was found in maize grain yield betweenmaize treated with Carbofuran and the other treatments in NyomII (Table 3). In Bafi a, there was no signifi cant difference betweentreatments. Similar results were obtained in farmers’ fi elds (Table 4).The grain yield in Bafi a was very low in all treatments.Maize grain yield of the insecticide treated plots was signifi cantlyhigher than those of the other treatments. Also, there was a slightmaize yield advantage of the maize-cowpea intercrop over the treatedsole maize in 1999 at Nyom II.Abundance of natural enemies of maize borersSix families of predator species were associated with stem borers in allthe treatments. These were Forfi culudae (Diaperasticus erythrocephala),Coccinellidae (Cheilomenes sulphurea sulphurea), Blattelidae (Blatellasp.), Araneidae, Formicidae and Hemiptera (Table 5). Overall, earwigs