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

摘要

The fall armyworm (FAW), (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 and Nixon (Hymenoptera: Platygastridae) have been found parasitizing eggs of the FAW. In Niger, the egg parasitoids encountered include sp. (Hymenoptera: Trichogrammatidae) and Nixon. 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, parasitized on average 78% of FAW eggs, compared to 25% for sp. was able to parasitize egg masses that were fully covered with scales, while sp. parasitized only uncovered egg masses. On-farm releases of in 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 of in augmentative releases against FAW in Africa.