Which companion plants affect the performance of green peach aphid on host plants? Testing of 12 candidate plants under laboratory conditions

Abstract

Intercropping of companion plants (CPs) that release distinct volatile compounds with horticultural crops has been proposed to improve pest management. Although CP extracts or essential oils have been reported to be efficient in disturbing the settling of insects such as aphids, the effect of using actual CPs remains relatively unknown. Our aim was to screen odorous CP species for their effect on the performance of green peach aphid,Myzus persicae Sulzer (Hemiptera: Aphididae), when released on adjacent pepper plants. Intercropping was tested in growth chambers using potted plants to avoid root interactions and homogenise the abiotic environment of CPs. Our results indicated that eight CP species—rosemary, African marigold, French marigold, geranium, lavender, basil, chives, and pot marigold—affected aphid performance by reducing the reproductive performance and/or settlement of females. Rosemary followed by African and French marigold was associated with the largest reduction in adult female and nymph number. Chemical analyses indicated that rosemary and French marigold emit specific volatiles. In contrast, four CP species (false yellowhead, thyme, savoury, and peppermint) were not associated with a significant change in aphid performance and emitted a lower diversity of volatiles. This screening of CPs under controlled conditions may be considered as a first step towards the identification of volatiles emitted by actual plants that can affect aphid performance and help the choice of CPs to optimise intercropping strategies

Repellence of Myzus persicae (Sulzer): evidence of two modes of action of volatiles from selected living aromatic plants

“…VOCs from rosemary ( Rosmarinus officinalis L.) plants are effective as a good aphid repellent . Similar properties have been reported for volatiles from lavender ( Lavandula latifolia L.) and peppermint ( Mentha piperita L.) …”

“…Basil ( Ocimum basilicum L.) volatiles are well known for their repulsive effects on different aphid species . VOCs from rosemary ( Rosmarinus officinalis L.) plants are effective as a good aphid repellent . Similar properties have been reported for volatiles from lavender ( Lavandula latifolia L.) and peppermint ( Mentha piperita L.) …”

“…Nana and Bonita Bolero) (Asteraceae)] were potted in 1 L pots except for L. latifolia (3 L pots). The choice of these species was mainly based on the previous work of Ben Issa et al . For T. patula , we tested two cultivars to check another source of variability in volatile emissions to determine if genetic variability influences the CP effectiveness.…”

“…Various odor effects of aromatic plants with potential to influence aphid behavior were investigated in previous studies. Ben Issa et al . reported that marigolds ( Tagetes spp.)…”

“…produce a large number of VOCs which can affect aphid performance, an aspect also verified in the plant essential oils . Basil ( Ocimum basilicum L.) volatiles are well known for their repulsive effects on different aphid species . VOCs from rosemary ( Rosmarinus officinalis L.) plants are effective as a good aphid repellent .…”