Antagonist effects of the leek Allium porrum as a companion plant on aphid host plant colonization

Xavier Baudry,Robin Van Havermaet,Arnaud Ameline,Géraldine Doury,Marc Lateur,Aude Couty,Yvelise Fourdrain

doi:10.1038/s41598-021-83580-8

Abstract

Combining a non-host plant (companion plant or CP) with a target cultivated plant is considered as a promising strategy to reduce pest pressure. Among the companion plants (CP) commonly used in integrated systems, those belonging to the Amaryllidaceae family (chives, garlic, onion, leek) exhibit characteristics related to certain volatile organic compounds (VOCs) with promising repellent potentialities. The aim of this work was to investigate the potential disruption of sweet pepper (host plant) colonization by the green peach aphid (Myzus persicae) when exposed to leek (Allium porrum) as a CP. Retention/dispersion, EPG and clip-cage/Petri dish laboratory experiments were thus performed to study the effect of leek VOCs on aphid settlement/migration, feeding behavior and life history traits parameters, respectively. This work revealed that leek as a CP had a negative effect on aphid feeding behavior, by disturbing the balance between phloem and xylem sap ingestion, but had no influence concerning aphid settlement. Surprisingly, leek as a CP triggered some unexpected probiotic effects on certain life history traits such as aphid survival, biomass, and fecundity, suggesting a possible hormetic effect of leek VOCs on aphid physiology. The possibility of experience-induced preference of aphids for leek VOCs was also discussed.

Highlights

Phytophagous insects evolve in complex and diverse environments and have to deal with various information sources, including odors, in order to achieve successful host plant selection and their subsequent reproductive cycle
Leek companioning had no significant effect on aphid settlement-migration between a sweet pepper alone and a sweet pepper associated with leek (Fig. 1)
This is in accordance with the work of[27] showing that M. persicae was attracted by sweet pepper and repelled by chive volatile organic compounds (VOCs) (Allium schoenoprasum L.), the association of those odors was neither repellent or attractive on M. persicae, a result that could be due to a masking or disrupting action of the companion plants (CP) on the host plant attractivity

Summary

Introduction

Phytophagous insects evolve in complex and diverse environments and have to deal with various information sources, including odors, in order to achieve successful host plant selection and their subsequent reproductive cycle. One of the main benefits of CPs lies with their propensity to emit volatile organic compounds (VOCs) that can contribute to the protection of the target plant from pests by mechanisms involving chemically masking p roperties[3,4] and/ or repelling e ffects[5]. The emission of volatile organic compounds (VOCs) by CPs has been shown to significantly modify host plant location by aphids by repelling them from their host p lant[9] and/or by reducing the host plant attractivity by masking its olfactory signature[10]. Species belonging to the Allium genus have been identified as significant sources of VOCs impacting insect pests colonization[24,25]. Field bioassays intercropping wheat (Triticum aestivum L.) with garlic (Allium sativum L.) showed a lower infestation by Sitobion avenae (Fabricius) on wheat associated with garlic in comparison to wheat monoculture, and better yields due to this association[28]

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Conclusion