Reduced fungicide applications improve insect pest control in grapevine

Agricultural intensification is a major driver of biodiversity decline in many species including arthropods. This may also affect important ecosystem services such as natural pest regulation. Traditional grapevine varieties rely on a high number of fungicide applications, which can be greatly reduced in novel fungus resistant cultivars. Additionally, in contrast to the traditional trellis system, the semi-minimal pruned hedge offers a structurally more diverse habitat for arthropods. We investigated natural control of the grapevine pest Lobesia botrana ([Denis & Schiffermüller], 1775) (Lepidoptera: Tortricidae) with artificial inoculation of grape bunches, egg baits, camera surveillance and beatsheet sampling of predators. Reduced fungicide applications enhanced densities of L. botrana predators along with increased egg predation and reduced damage of inoculated grape bunches. Minimal pruning did not have a clear effect. Improved pest control potential adds to other advantages of reduced fungicide applications. Planting fungus-resistant varieties should be augmented, potentially also in other crop systems that rely heavily on fungicides.