Integrating Plant Volatile Scents in Sustainable IPM Approaches for Fall Armyworm Control

Abstract

Since the invasion of the fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae) into new regions, studies have oriented toward low-cost management tools and methods. This study assessed the effects of volatile scents that are naturally emitted by essential oil (EO) plants on the severity of FAW and populations of its natural enemies. Plants of Cymbopogon citratus, C. nardus, C. schoenanthus (Poales: Poaceae), Mesosphaerum (Hyptis) suaveolens, Ocimum gratissimum, O. citriodorum and O. basilicum (Lamiales: Lamiaceae) were planted alongside maize during three on-station experiments. Egg mass and larval densities, damaged leaves and plants, damage scores and abundance of parasitoids and predators were assessed on maize plots. Although no significant difference was observed for egg masses, maize plants next to C. citratus, C. schoenanthus, O. gratissimum and O. citriodorum recorded lower larval densities. However, percent damaged plants and damage scores were lower on maize plants next to C. schoenanthus and O. citriodorum, and larvae collected from maize next to these plants recorded the highest parasitism rates. These two plants were also among the four treatments that recorded the highest parasitism of egg masses. The natural enemies collected included one egg parasitoid, one egg-larval parasitoid, three larval parasitoids and seven predator species. Plant age was negatively correlated with egg mass and larval densities, and parasitism rates were positively correlated with egg mass and larval densities. C. schoenanthus and O. citriodorum mitigate fall armyworm damage while promoting natural enemy populations.