Winter host component reduces colonization by bird-cherry-oat aphid,Rhopalosiphum padi (L.) (homoptera, aphididae), and other aphids in cereal fields.

Methyl salicylate, a volatile component ofPrunus padus, the winter host ofRhopalosiphum padi, was found to reduce colonization of the summer host by this aphid. The compound was identified by gas chromatographic analysis coupled with recordings from cells in the primary rhinarium on the sixth antennal segment of the aphid. Methyl salicylate eliminated the attractancy of oat leaves to spring migrants in olfactometer tests. In Sweden, this compound significantly decreased colonization of field grown cereals byR. padi and in the U.K., populations ofSitobion avenae andMetopolophium dirhodum were significantly lower on treated plots.