Journal of Pest Science (2021) 94, 1105-1118

Santosh V. Revadi, Vito Antonio Giannuzzi, Ramesh R. Vetukuri, William B. Walker III and Paul G. Becher (2021)
Larval response to frass and guaiacol: detection of an attractant produced by bacteria from Spodoptera littoralis frass
Journal of Pest Science 94 (4), 1105-1118
Abstract: Larval frass in herbivorous lepidopterans is mainly composed of plant-derived material and microbes from the gut. Despite the fact that frass from conspecific larvae repels female moths in Spodoptera littoralis from oviposition, the role of frass volatiles on larval foraging behavior is largely unknown. Here, we show that larvae of S. littoralis walk upwind to larval frass volatiles in a wind tunnel assay. We identified the frass volatile guaiacol (2-methoxyphenol) as key ligand for the S. littoralis odorant receptor (OR) SlitOr59 which we expressed heterologously. We isolated guaiacol-producing bacteria identified as Serratia marcescens from frass of larvae that were fed on cotton, and Enterobacter cloacae, E. ludwigii and Klebsiella sp. from frass derived from cabbage-fed larvae. In addition to guaiacol, we also identified volatiles acetoin, 3-methyl-1-butanol and dimethyl disulfide, in large proportions in headspace collections from the bacteria. A Y-tube olfactometer assay showed that fourth instar S. littoralis larvae are attracted to guaiacol. Moreover, cotton leaves treated with the insecticide Spinosad and guaiacol were highly attractive to the larvae. Our results provide a basis for management of the pest by directly targeting larvae, based on an attract-and-kill strategy. Further studies are needed to test the application of guaiacol for semiochemical-based pest management of Spodoptera pest species.
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Link to article at publishers website

Research topic(s) for pests/diseases/weeds:
pheromones/attractants/traps
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Spodoptera littoralis	Cotton (Gossypium)