Parasitism of Locally Recruited Egg Parasitoids of the Fall Armyworm in Africa

The fall armyworm (FAW),Spodoptera frugiperda(J.E. Smith) (Lepidoptera: Noctuidae), is an insect native to the tropical and subtropical Americas that has recently spread to Africa, where it predominately attacks maize, sorghum and other plant species. Biological control is an environmentally friendly way of combatting the pest and contributes to an integrated pest management approach. In Africa, several trichogrammatid parasitoids andTelenomus remusNixon (Hymenoptera: Platygastridae) have been found parasitizing eggs of the FAW. In Niger, the egg parasitoids encountered includeTrichogrammatoideasp. (Hymenoptera: Trichogrammatidae) andTelenomus remusNixon. Parasitism of the FAW eggs by the two egg parasitoids was assessed in the laboratory, followed by field testing on sentinel eggs. In the laboratory,T. remusparasitized on average 78% of FAW eggs, compared to 25% forTrichogrammatoideasp.Telenomus remuswas able to parasitize egg masses that were fully covered with scales, whileTrichogrammatoideasp. parasitized only uncovered egg masses. On-farm releases ofT. remusin sorghum fields caused up to 64% of FAW egg parasitism. Parasitized eggs yielded viable progeny, which can contribute to FAW egg parasitism build-up during the cropping season. Our findings lay the groundwork for the use ofT. remusin augmentative releases against FAW in Africa.