Identification of Chelonus sp. from Zambia and Its Performance on Different Aged Eggs of Spodoptera frugiperda

Abstract

The fall armyworm (FAW), <i>Spodoptera frugiperda</i> (J. E. Smith) (Lepidoptera: Noctuidae), is a migratory pest endemic, to tropical and subtropical regions of America. Biological control can effectively and sustainably control pests over a long period of time while reducing the frequency of pesticide use and ensuring the safety of agricultural produce. In our study, the egg-larval <i>Chelonus</i> species (<i>Chelonus bifoveolatus</i>) from parasitized eggs of <i>Spodoptera frugiperda</i> in Zambia were described and identified based on morphological and genetic characteristics. To evaluate the efficiency of <i>C. bifoveolatus</i>, their parasitism suitability on 0- to 2-day FAW eggs under laboratory conditions was compared. The results showed that <i>C. bifoveolatus</i> could accept all FAW eggs at 0-, 1- and 2-day-old age and complete development successfully. Significant differences were found among 0-, 1-, and 2-day-old host eggs with respect to egg-larva developmental duration of <i>C. bifoveolatus</i>, and the egg-larva developmental duration on 2-day-old eggs was significantly lower than those on 0- and 1-day-old eggs. No significant differences were observed in the parasitism, pupation, emergence, and female rates for <i>C. bifoveolatus</i> on various age eggs of FAW. Generally, the parasitism rate, pupal rate, and emergence rate at various ages of FAW eggs were higher than 90%, 75%, and 82%, respectively, and the longevity of female parasitoids was longer than male parasitoids, and the sex ratio of females to males was nearly 1:1. Our results indicate that <i>C. bifoveolatus</i> performed well on various ages of FAW eggs and is a potential biological control agent against FAW in Africa.