Intercropping impacts the host location behaviour and population growth of aphids

Abstract

Increasing intrafield plant diversity has been shown to regulate pest populations in various agroecosystems. Among the suggested mechanisms for this bottom-up pest control, the disruptive crop hypothesis states that herbivores' abilities to locate and colonize their host plants are reduced by the presence of non-host plants. Under laboratory conditions, we evaluated how intercropping wheat and legumes modifies the behaviour of apterous cereal aphids, Sitobion avenae (Fabricius) (Hemiptera: Aphididae), in terms of host plant location and population growth. We compared two intercropping systemssoft winter wheat, Triticum aestivum L. (Poaceae), associated with winter pea, Pisum sativum L., or with white clover, Trifolium repens L. (both Fabaceae)and sole stands of soft winter wheat. Aphids needed more time to locate their wheat host plant and then spent less time on wheat when it was intercropped with clover. At the population level, and accounting for host plant biomass, only intercropping wheat with clover significantly reduced aphid densities on wheat, as this was particularly disruptive to S. avenae behaviour and population growth. Our laboratory study points out that the species used as non-host plants and their density are important parameters that should be taken into account in field studies on intercropping systems.

Impact of Cover Crops on Insect Community Dynamics in Organic Farming

“…To conclude, our results are in congruence with other studies which collectively demonstrate that intercropping different cover crops can influence the insect diversity during the cropping season [29,34,[36][37][38]43,44] and bridge a few, if not all, insects and their benefits, if any, to the subsequent cash crop [41]. However, it is important to plan and select appropriate cover crops for maximum benefits that are both species-and location-specific.…”

“…In addition, intercropping is known to affect the host location of a suitable plant by the insect pest. For instance, Mansion-Vaquie [34] reported the increased time taken by cereal aphids (Sitobion avenae) to locate wheat plants (Triticum aestivum) in a diversified cropping system than in a monoculture. So, it is possible that herbivore abundance remained constant during the early and the late season in the course of locating and feeding on the appropriate host plant.…”

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

“…The use of CPs can represent an effective strategy to disturb their host plant colonization process 6 at various steps comprising adult migration, landing, settlement and reproduction 7 , 8 . 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 plant 9 and/or by reducing the host plant attractivity by masking its olfactory signature 10 . Several works have demonstrated that using CPs can also impact aphids life history traits and significantly reduce fecundity 11 .…”

Barriers and Levers to Developing Wheat–Pea Intercropping in Europe: A Review

“…If mechanical weed control is not possible for the intercrop in the same row, spraying is necessary. In addition, certain pests such as pigeons, aphids, pea Sitones, and Mycosphaerella pinodes must still be controlled [20,55,[60][61][62][63][64][65]. This must be done in addition to disease treatments that may be necessary for both species despite the beneficial effect that intercropping has on pathogen dynamics [66].…”