Oviposition behaviour and larval attraction of the fallarmyworm Spodoptera frugiperda (Lepidoptera: Noctuidae)to different maize

Phytophagous insects likely select suitable host plants for oviposition based on olfactory and tactile cues. However, details of how insects differentiate among different plant varieties are often unclear. The fall armyworm (Spodoptera frugiperda J. E. Smith) is a highly destructive pest on maize, but little is known about the attraction and oviposition preference of S. frugiperda to different maize varieties, particularly in the context of sub-Saharan Africa, where the insect is a major threat to maize production. We determined the oviposition preference of S. frugiperda females on six different maize plant varieties three of which were hybrid varieties and three were open-pollinated varieties, in multiple-choice and no-choice assays. We also evaluated the attraction preference of S. frugiperda larvae on these maize varieties, using an olfactometer bioassay. We found that S. frugiperda females oviposited significantly less egg masses on the hybrid varieties DEKAIB and 30Y87 than on the other varieties tested and that females oviposited less on the hybrid maize varieties compared to the open-pollinated maize varieties overall. Additionally, we found that S. frugiperda larvae were more attracted to the open-pollinated variety LMFP than to clean air, which was not the case for any of the other maize varieties tested. Taken together, our results show that S. frugiperda responds differentially to the different maize varieties and that hybrid maize varieties seem less attractive. Further investigating the chemistry of hybrid maize varieties like DEKAIB might yield clues on how to breed maize varieties with increased resistance against S. frugiperda infestation.