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bioRxiv · 10.1101/653113

Partial-resistance against aphids in wild barley reduces the oviposition success of the generalist parasitoid, Aphidius colemani

Leybourne, D. J.·Valentine, T. A.·Bos, J. I. B.·Karley, A. J.
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Abstract

Aphids are significant agricultural pests of cereal crops with a worldwide distribution. The control of aphids in agricultural systems is currently heavily reliant on insecticidal compounds, but it is becoming increasingly apparent that chemical-based control of agricultural pests has far-reaching unintended consequences on agro-ecosystems. As a result, more sustainable means of aphid control are becoming increasingly desirable. Potential options include increasing plant resistance against aphids, promoting biocontrol, and the combined use of both strategies. When used together it is important to understand how, and to what extent, increased plant resistance against aphids affects the success of biocontrol agents. In this current study, we examine how partial-resistance against cereal aphids in a wild relative of barley, Hordeum spontaneum 5 (Hsp5), affects the success of the common parasitoid of cereal aphids, Aphidius colemani. We show that the parasitism success of A. colemani attacking nymphs of the bird cherry-oat aphid, Rhopalosiphum padi, contained on Hsp5 is reduced compared with the parasitism success of wasps attacking R. padi nymphs feeding on a susceptible modern cultivar of barley, H. vulgare cv. Concerto. Explanta parasitism assays showed that the in parasitoid success is a direct effect of the plant environment (such as differential architectural traits), rather than an indirect effect dur to a decrease in aphid suitability resulting from increased resistance against aphids in Hsp5. Our study highlights the importance of understanding the direct and indirect effects of plant resistance against aphids on biocontrol strategies.

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Leybourne, D. J., Valentine, T. A., Bos, J. I. B., Karley, A. J.. 2019-05-29. Partial-resistance against aphids in wild barley reduces the oviposition success of the generalist parasitoid, Aphidius colemani. https://doi.org/10.1101/653113

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