Organic farming at local and landscape scales fosters biological pest control in vineyards

Abstract

While organic farming practices, which are often promoted as models of ecological intensification, generally enhance biodiversity, their effects on the delivery of ecosystem services, such as biological pest control, are still unknown. Here, using a multi‐scale hierarchical design in southwestern France, we examined the effects of organic farming and seminatural habitats at the local and landscape scales on biological control services of three pests, including weeds and insects, in 42 vineyards. Organic farming at the local and landscape scales was beneficial to the mean and temporal stability of biological control services, while the proportion of seminatural habitats in the landscape reduced the level of biological pest control potential. The effects of organic farming and seminatural habitats across spatial scales varied with the type of prey considered and with time. Egg moth removal rates were higher in fields under organic management compared to conventional management while weed seed removal rates increased with the proportion of organic farming in the landscape. Larval removal rates as well as seed removal rates were always more stable within time in organic fields than in conventional fields. Moreover, independently of farming system type, local variables describing the agricultural management intensity, such as pesticide use or crop productivity, were also found to be important variables explaining levels of biological control services. Pesticide use tended to reduce biological control potential, while crop productivity was associated with contrasting biological control responses depending on the pest type. Our study demonstrates the need to target multiple spatial scales and to consider farming practices, as well as the proportion of seminatural habitats, to design functional landscapes that optimize biological pest control services.

Organic farming expansion drives natural enemy abundance but not diversity in vineyard‐dominated landscapes

“…Moreover, we found that organic farming reduces natural enemy richness and benefits to the most dominant species in vineyards (Figure ). As we previously demonstrated that organic farming fosters pest control services in vineyard landscapes (Muneret et al, ), our studies suggest that pest control might be provided by a limited number of dominant species. This is in line with a recent synthesis on another key ecosystem services, showing that pollination is provided by a restrictive number of abundant pollinator species in croplands (Kleijn et al, ).…”

“…The intensity of pesticide application was calculated using the Treatment Frequency Index (“TFI”) which is the sum of all the ratios between the applied and the recommended dose for each pesticide application (OECD, ). Tillage intensity was evaluated by calculating the “tillage intensity index” which summarizes the number of tilling operations per year weighted by the area involved each time (Muneret et al, ). We also measured vine trunk density and crop productivity.…”

“…Moreover, a recent synthesis at the global scale revealed strong variability in direction and effect size of semi‐natural habitats on predators and biological pest control (Karp et al, ). Thus, considering farming practices at multiple spatial scales, notably the proportion of organic farming at the landscape scale, should reduce unexplained variation in these relationships (Muneret, Auriol, Thiéry, & Rusch, ).…”

Landscape composition and configuration affect the abundance of the olive moth (Prays oleae, Bernard) in olive groves

“…More works have found that natural habitats failed in supporting biological control. For instance, Muneret et al (2019) analyzed the effect of a gradient of natural habitats and organic farming land cover on Tortricidae Lobesia botrana (Dennis & Schiffermüller) and Eupoecilia ambiguella (Hübner), important grape moth pests. These authors found that organic farming enhanced biological control, however increasing the proportion of seminatural habitats had no or negative effects on the potential biological control.…”

Diversity of Species and the Occurrence and Development of a Specialized Pest Population—A Review Article

“…The biodiversity of farmlands has significantly declined, which can be explained by the intensification of agricultural production [32][33][34]. In consequence, this decline may reduce the abundance of natural enemies and their effects on pest species [35][36][37][38].…”