Non-host volatiles do not affect host acceptance by alate virginoparae of Rhopalosiphum padi (Hemiptera: Aphididae) settled on the host plant surface

Ruby Olivares-Donoso,Hermann M Niemeyer

doi:10.14411/eje.2005.044

Abstract

Using electrical penetration graphs to monitor aphid feeding, it was shown that volatiles of a non-host plant (alfalfa, Medicago sativa L.) did not disrupt the process of host acceptance by alate virginoparae of the birdcherry-oat aphid, Rhopalosiphum padi L., once it was settled on a host plant (wheat, Triticum aestivum L.).

Highlights

Host plant selection by aphids consists of a sequence of four consecutive steps: 1) attraction and landing on the plant, 2) evaluation of the leaf surface and probing of subepidermic tissues, 3) deep probing of plant tissues, and 4) evaluation of the phloem sap (Niemeyer, 1990)
The aim of this work was to determine if the volatiles of a non-cereal, dicot non-host plant could disrupt the process of host acceptance by alate virginoparae of the birdcherry-oat aphid, Rhopalosiphum padi L., once it is settled on a host plant, using electrical penetration graphs to monitor aphid feeding
Wheat seedlings at decimal growth stage 12 (Zadoks et al, 1974) and ca. 9 cm tall were used for aphid stylet monitoring and for emission of volatiles, and two-week old alfalfa seedlings were used for emission of volatiles

Summary

Introduction

Host plant selection by aphids consists of a sequence of four consecutive steps: 1) attraction and landing on the plant, 2) evaluation of the leaf surface and probing of subepidermic tissues, 3) deep probing of plant tissues, and 4) evaluation of the phloem sap (Niemeyer, 1990). During this process the aphids receive different sensory cues including visual, olfactory, gustatory, and tactile stimuli (Dixon, 1998). The attractiveness of host plant volatiles before aphid landing can be disrupted by the presence of nonhost plant volatiles (e.g. Nottingham & Hardie, 1993; Hori & Komatsu, 1997). The aim of this work was to determine if the volatiles of a non-cereal, dicot non-host plant (alfalfa, Medicago sativa L.) could disrupt the process of host acceptance (steps 2, 3 and 4) by alate virginoparae of the birdcherry-oat aphid, Rhopalosiphum padi L., once it is settled on a host plant (wheat, Triticum aestivum L.), using electrical penetration graphs to monitor aphid feeding

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Conclusion