Acceptability and suitability of some Poaceae plants for fall armyworm feeding and oviposition

Abstract

Background: The fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), has invaded new geographical regions, now spanning Africa, Asia, Oceania and Europe, from its native distribution in the last decade. Little is known about FAW host plants in recently invaded habitats; although more than 300 hosts have been reported in the Americas, its native habitat. In our study, we evaluated the acceptability and suitability of 12 cultivated varieties of plants from Africa, in the family Poaceae, for FAW herbivory and oviposition. Methods: Experiments investigating larval development, no-choice oviposition, and no-choice larval arrestment-feeding were conducted to evaluate the insect´s ability to utilize these plants for survival. Results: We found that Pennisetum ex. Sengerema, Brachiaria brizantha , Brachiaria ex. Mwanza, Panicum maximum ex. Machakos, Melinis minutiflora and S . bicolor cv. Ochuti were unsuitable plants for FAW larvae. In contrast, Zea mays HB WH505, Panicum glaucum Nutrifeed, S . bicolor cv. Serena and P . purpureum were suitable plants and S . bicolor cv. Ochuti was well accepted for egg-laying. However, M . minutiflora was not accepted for egg-laying but retained early instar larvae. S . bicolor cv. Andiwo was not well accepted for egg-laying and S . bicolor cv. Gadam yielded lighter pupae. Conclusions: Our findings provide insights into the performance of FAW larvae on different Poaceae plants and how well they are accepted by FAW female moths for oviposition. We recommend to study further selected plants ( M . minutiflora , S . bicolor cv. Andiwo and S . bicolor cv. Ochuti), as potential trap or repellent plants for different FAW life stages, in choice tests. This knowledge will help to design ecologically based management strategies for FAW in its new habitats in Kenya and beyond.