An Insight in the Reproductive Biology of Therophilus javanus (Hymenoptera, Braconidae, and Agathidinae), a Potential Biological Control Agent against the Legume Pod Borer (Lepidoptera, Crambidae).

Djibril Aboubakar Souna,Aimé Bokonon-Ganta,Antonino Cusumano,Barry Robert Pittendrigh,Marc Ravallec,Anne-Nathalie Volkoff,Manuele Tamò

doi:10.1155/2017/3156534

Abstract

Therophilus javanus is a koinobiont, solitary larval endoparasitoid currently being considered as a biological control agent against the pod borer Maruca vitrata, a devastating cowpea pest causing 20–80% crop losses in West Africa. We investigated ovary morphology and anatomy, oogenesis, potential fecundity, and egg load in T. javanus, as well as the effect of factors such as age of the female and parasitoid/host size at oviposition on egg load. The number of ovarioles was found to be variable and significantly influenced by the age/size of the M. vitrata caterpillar when parasitized. Egg load also was strongly influenced by both the instar of M. vitrata caterpillar at the moment of parasitism and wasp age. The practical implications of these findings for improving mass rearing of the parasitoid toward successful biological control of M. vitrata are discussed.

Highlights

IntroductionM. testulalis) (Lepidoptera: Crambidae) is an important pest of cowpea, Vigna unguiculata L
The legume pod borer Maruca vitrata (Fabricius)
High parasitism rates of T. javanus on M. vitrata caterpillars have been reported in soybean and yard-long beans fields in tropical Asia, Lao PDR, Vietnam, and Southern Taiwan [3, 4]

Summary

Introduction

M. testulalis) (Lepidoptera: Crambidae) is an important pest of cowpea, Vigna unguiculata L. Walp (Fabales: Fabaceae), a widely cultivated legume crop in Sub-Saharan Africa, and can cause yield losses in the range of 20–80% [1]. According to taxonomic and population genetic studies, the putative area of origin of this pest is assigned to South Asia [2]. High parasitism rates of T. javanus on M. vitrata caterpillars have been reported in soybean and yard-long beans fields in tropical Asia, Lao PDR, Vietnam, and Southern Taiwan [3, 4]. T. javanus seems an excellent candidate for use as a biological control agent against M. vitrata in West Africa. The development of biological control relying on T. javanus releases requires a thorough knowledge of its basic biology, which has not been investigated yet

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Conclusion