Olfactory response of Myzus persicae (Homoptera: Aphididae) to volatiles from leek and chive:: Potential for intercropping with sweet pepper

Odour-mediated effects of leek Allium porum and chives Allium schoenoprasum (Alliaceae) on the host searching behaviour of the aphid Myzus persicae (Sulzer) (Homoptera: Aphididae) were studied. In an olfactometer, odour of the host plant sweet pepper Capsicum annuum L. (Solanaceae) was significantly attractive, whereas odour of chives was significantly repellent. Combined odour of sweet pepper and chives was neither attractive nor repellent. When sweet pepper plants were exposed to volatiles from chives for five days, their odour subsequently became repellent to M. persicae. An extract of leek plants was significantly repellent to aphids in the olfactometer, as were sweet pepper plants sprayed with this extract. Because both leek and chives can disrupt host finding by the aphid, both plants have potential for intercropping with sweet pepper. If successful in the field, such a system could bring economic benefits for farmers in the wet zone of Sri Lanka and other parts of the world.