Semiochemical use is a promising way to reduce damage from pests by improving natural control in agro-ecosystems. The aphid alarm pheromone (E)-⊎-farnesene (E⊎F) and herbivore-induced methyl salicylate (MeSA) are two volatile cues to induce changes in aphid behavior with functional significance. Because of limitations related to the volatility and oxidization of E⊎F and MeSA under natural conditions, slow-release and antioxidant techniques should be developed and optimized before application. Here, a slow-release alginate bead of E⊎F mixed with MeSA was first designed and manufactured. We hypothesized that a mixture of these two semiochemicals could be effective in controlling Sitobion miscanthi in wheat crops. Both MeSA and E⊎F in alginate beads were released stably and continuously for at least 15 days in the laboratory, whereas E⊎F in paraffin oil and pure MeSA were released for only 2 and 7 days, respectively. In 2018 field experiments, E⊎F and MeSA alone or in association significantly decreased the abundance of alate and apterous aphids. An increased abundance of mummified aphids enhanced by higher parasitism rates was observed when using E⊎F and MeSA in association, with a significant reduction of apterous abundance, more so than E⊎F or MeSA alone. In 2019, plots treated with a mixture of E⊎F and MeSA showed significantly decreased abundance of alate and apterous aphids with higher parasitism rates compared with the control. The new slow-release alginate bead containing a mixture of E⊎F with MeSA could be the most efficient formulation to control S. miscanthi population by attracting parasitoids in the wheat agro-ecosystem.

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Sitobion avenae (Fabricius) is a major insect pest of wheat worldwide that reduces crop yield and quality annually. Few germplasm resources with resistant genes to aphids have been identified and characterized. Here, octoploid Trititrigia, a species used in wheat distant hybridization breeding, was found to be repellent to S. avenae after 2 year field investigations and associated with physiological and behavioral assays. Linalool monoterpene was identified to accumulate dominantly in plants in response to S. avenae infestation. We cloned the resistance gene OtLIS by assembling the transcriptome of aphid-infested or healthy octoploid Trititrigia. Functional characterization analysis indicated that OtLIS encoded a terpene synthase and conferred resistance to S. avenae by linalool emission before and after aphid feeding. Our study suggests that the octoploid Trititrigia with the aphid-resistant gene OtLIS may have potential as a target resource for further breeding aphid-resistant wheat cultivars.