Pesticide use in vineyards is affected by semi-natural habitats and organic farming share in the landscape

Abstract

Reducing pesticide use in agricultural landscapes involves understanding the environmental drivers that affect pesticide application and its subsequent effect on pests. Landscape diversification has been found to benefit natural enemies of pests that may lead to lower pest pressure, but its effect on pests and pesticide use, in particular, remains unclear. We investigated how the proportion of organic farming and semi-natural habitats in the landscape affect pesticide use in conventional and organic vineyards based on 22 pairs of vineyards selected along landscape gradients. We quantified both insecticide and fungicide use by farmers as vineyards are heavily sprayed against insect pests and pathogens. Our study indicates that the share of organic farming in the total vineyard area and the proportion of semi-natural habitats in the landscape influence pesticide use. We found a tendency for insecticide use to increase with the share of vineyards under organic farming in the landscape, both in organic and conventional fields. Fungicide use followed the same pattern but only in conventional fields. Significant increases in pesticide use due to a higher share of organic farming were small, rarely exceeding 14% of the treatment frequency index. Notably, our results revealed contrasted effects of the proportion of semi-natural habitats on pesticide use between organic and conventional farming. Landscapes with a higher proportion of semi-natural habitats tended to increase fungicide use in conventional fields while insecticide use tended to decrease in organic fields. Our results demonstrate that designing landscapes that limit pesticide use should consider farming practices and semi-natural habitats within the landscape to favour beneficial effects on pest control while minimising potential adverse effects.