Using service plants for regulating crop pests

The ability to regulate crop pests with limited use of synthetic pesticides is a major challenge for the agroecological transition. Service plants are a promising option. Unlike crop plants grown for agricultural production, they are used in fields to provide ecosystem services, such as soil fertility, carbon sequestration or pest regulation. They can be used in different ways: inserted either in intercropping with the crops, or in rotation with the crops, or in field edges (for example as flower strips).

The potential of service plants to regulate one category of pest at a time has already been demonstrated in previous studies, i.e., insect pests, weed plants, aerial pathogens or soil-borne pests. However an overall view is required to analyse their potential to regulate several pest categories at a time, while limiting disservices (i.e. negative impacts) of service plants. The study conducted by INRAE researchers, published in the journal Agronomy for Sustainable Development, aims to fill this gap by adopting an original approach based on service plant traits.

The results show that, overall, the same service plant traits contribute to regulating several categories of pests. For example, using tall, wide and fast-growing service plants promotes the regulation of weed plants, insect pests, soil-borne pests and aerial pathogens. Although caution should be exercised at this stage, the results show the good potential of service plants for multi-pest regulation.

However, this study highlights that these same service plant traits can generate disservices, such as competing with the main crop for resources or promoting non-targeted pests. The challenge lies at least as much in mitigating these disservices as in promoting multi-pest regulation. The level of incompatibility between these two goals depends on how the service plants are inserted and managed in the cropping systems.