Evidence of Leaf Consumption Rate Decrease in Fall Armyworm, Spodoptera frugiperda, Larvae Parasitized by Coccygidium luteum

Abstract

Biological control is one of the best options for the sustainable management of the invasive maize pest <i>Spodoptera frugiperda</i> in Africa. However, there is limited knowledge of the efficacy of native natural enemies of <i>S. frugiperda</i> and their potential use in integrated pest management. The endoparasitoid wasp <i>Coccygidium luteum</i> is one of the natural enemies of <i>S. frugiperda</i> in Africa. This study assessed, under laboratory conditions, the effect of <i>C. luteum</i> on the leaf consumption rate of its host. Fifty first instar <i>S. frugiperda</i> larvae were exposed to <i>C. luteum</i> for oviposition and the maize leaf consumption rate of parasitized larvae was assessed and compared to 50 unparasitized larvae from the same cohort. <i>Coccygidium</i> <i>luteum</i> completed a generation, from egg to adult emergence, in 16.7 days. The leaf consumption rate of parasitized <i>S. frugiperda</i> larvae declined gradually compared to unparasitized larvae and the overall consumption reduction by parasitized <i>S. frugiperda</i> larvae was 89%. Our findings show that <i>C. luteum</i> could reduce damage caused by <i>S. frugiperda</i> to maize farms but, prior to its use in biological control programmes, further studies are needed to assess potential parasitism rates in field conditions and develop a cost-effective mass production system.