LAUSR

BACKGROUND Aphids are sap-sucking insect pests of economic importance. They exhibit polyphenism producing two kinds of morphotypes; winged (alate) and wingless (aptera) morphs. While wingless morphs can be controlled by insecticides, winged morphs are a challenge for targeted control measures as they can fly. Although coloured sticky traps are used to control and monitor winged aphids, only a small populations are trapped, making sticky traps less effective in controlling aphids. Studies have shown that fragrant oils applied to sticky traps increased attraction of sap-sucking insects like whiteflies and thrips. Here, we tested selected essential oils for their attractiveness to winged A. gossypii in potato fields. RESULTS In field assays, selected essential oils with yellow or colourless sticky traps attracted more winged A. gossypii than controls. The combination of yellow traps baited with essential oils attracted ~2-3-fold more winged A. gossypii than did colourless traps baited with essential oils. In a multi-cycle two year study, yellow sticky traps baited with basil oil consistently attracted more winged A. gossypii than yellow sticky traps baited with lavender, geranium or tea tree oils. In electrophysiological studies, winged A. gossypii's antennae responded consistently to estragole in basil oil. In olfactometer assays with estragole, winged A. gossypii spent significantly more time in the treatment arm of the olfactometer than in the control arm, validating estragole's attractiveness. Further, yellow sticky traps baited with pure estragole, in potato fields, attracted similar number of winged A. gossypii as yellow sticky traps baited with basil oil. CONCLUSION Our findings demonstrate the potential of using basil oil as a potential attractant to improve the efficacy of sticky traps in monitoring and control of winged aphids. This article is protected by copyright. All rights reserved.