Companion Plants for Aphid Pest Management

Abstract

A potential strategy for controlling pests is through the use of “companion plants” within a crop system. This strategy has been used in several trials to fight against a major crop insect pest: the aphid. We reviewed the literature to highlight the major mechanisms by which a companion plant may act. Trials carried out under laboratory or field conditions revealed that companion plants operate through several mechanisms. A companion plant may be associated with a target crop for various reasons. Firstly, it can attract aphids and draw them away from their host plants. Secondly, it can alter the recognition of the host plant. This effect is mostly attributed to companion plant volatiles since they disturb the aphid host plant location, and additionally they may react chemically and physiologically with the host plant, making it an unsuitable host for aphids. Thirdly, it can attract natural enemies by providing shelter and food resources. In this review, the feasibility of using companion plants is discussed. We conclude that many factors need to be taken into account for a successful companion plant strategy. For the best long-term results, companion plant strategies have to be combined with other alternative approaches against aphids.

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

“…using natural products, release of natural enemies, and the push‐pull strategy) have been investigated to reduce aphid infestations and limit their damage to an acceptable level. Among these methods, intercropping with companion plants (CPs) is a promising eco‐friendly approach . These CPs can be suggested as natural diffusers of semiochemicals, primarily monoterpenes (C 10 H 16 ), and sesquiterpenes (C 15 H 24 ), which function as repellents or arrestants and can increase the protection of cultivated plants towards aphids .…”

“…These CPs can be suggested as natural diffusers of semiochemicals, primarily monoterpenes (C 10 H 16 ), and sesquiterpenes (C 15 H 24 ), which function as repellents or arrestants and can increase the protection of cultivated plants towards aphids . The perception of potentially repellent plant volatile organic compounds (VOCs) through aphids sensilla (rhinaria, located in the insect antenna) can increase the deterrence effect, keeping populations away from crops, disrupting their settlement and, most of all, reducing their performance and thus inhibiting the development of their population …”

“…Scientists have put great effort into understanding CP volatile effects on pests. The properties of plant VOCs against aphids, such us repellency, have been frequently discussed in previous studies . In contrast, as it is difficult to monitor whole‐system experiments, few studies were focused on their mode of action or on the underlying mechanisms …”

Intercropping impacts the host location behaviour and population growth of aphids

“…At the field level, increased diversity is mainly achieved by intercropping (Andow, 1991), defined as 'the cultivation of two or more species of crop in such a way that they interact agronomically' ( Vandermeer, 1989). We may distinguish two types of intercropping: 'true intercropping' (Willey, 1979), that is the simultaneous cultivation of two cash crops, and 'companion cropping', the cultivation of a cash crop and a beneficial non-crop (Ben-Issa et al, 2017;Verret et al, 2017). An increase in productivity in intercropping systems may be achieved through an improved yield per unit area, due to complementary use of resources, facilitation, and/or increased pest regulation (Brooker et al, 2015).…”

“…Several hypotheses explain how increasing intrafield diversity may promote bottom-up control. A non-host plant may interfere with the chemical cues used by a herbivore to locate its host plant by masking the host's odours, altering the host's chemical profile, or introducing repellent compounds (Randlkofer et al, 2010;Ben-Issa et al, 2017). A non-host plant may interfere with the chemical cues used by a herbivore to locate its host plant by masking the host's odours, altering the host's chemical profile, or introducing repellent compounds (Randlkofer et al, 2010;Ben-Issa et al, 2017).…”