Evaluation of African Maize Cultivars for Resistance to Fall Armyworm Spodoptera frugiperda(J. E. Smith) (Lepidoptera:Noctuidae) Larvae

The fall armyworm (FAW) has recently invaded and become an important pest of maizein Africa causing yield losses reaching up to a third of maize annual production. The present studyevaluated different aspects of resistance of six maize cultivars, cropped by farmers in Kenya, toFAW larvae feeding under laboratory and field conditions. We assessed the arrestment and feedingof FAW neonate larvae in no-choice and choice experiments, development of larvae-pupae, foodassimilation under laboratory conditions and plant damage in a field experiment. We did not findcomplete resistance to FAW feeding in the evaluated maize cultivars, but we detected differences inacceptance and preference when FAW larvae were given a choice between certain cultivars. Moreover,the smallest pupal weight and the lowest growth index were found on ’SC Duma 43′leaves, whichsuggests an effect of antibiosis of this maize hybrid against FAW larvae. In contrast, the highestgrowth index was recorded on ‘Rachar ’ and the greatest pupal weight was found on ‘Nyamula’ and‘Rachar’. The density of trichomes on the leaves of these maize cultivars seems not to be directlyrelated to the preference of neonates for feeding. Plant damage scores were not statistically differentbetween cultivars in the field neither under natural nor artificial infestation. However, plant damagescores in ‘Nyamula’ and ‘Jowi’ tended to be lower in the two last samplings of the season comparedto the two initial samplings under artificial infestation. Our study provides insight into FAW larvalpreferences and performance on some African maize cultivars, showing that there are differencesbetween cultivars in these variables; but high levels of resistance to larvae feeding were not found.