Less field-level insecticides, but not fungicides, in small perennial crop fields and landscapes with woodlands and organic farming

Abstract

CONTEXTA large body of evidence suggests that landscape management may limit the use of pesticides in agricultural systems. However, this hypothesis is largely based on studies about biological pest control service, and the effects of landscape context on pesticide use remain poorly investigated. OBJECTIVEHere, we investigated how the proportion of host crops and semi-natural habitats affected the local use of fungicides and insecticides in the most treated crops in France, i.e., apple orchards and vineyards. METHODSUsing pesticide use information at the national level from 64 apple orchards and 138 vineyards monitored between 2014 and 2019, we investigated how local field size, several aspects of landscape context (proportion of host crops, share of organic host crop, proportion of woodlands and grasslands) as well as the weather context affect the frequency, timing and diversity of local fungicide and insecticide use. RESULTS AND CONCLUSIONSOur results highlight that landscape-scale management could reduce the use of insecticides in agricultural landscapes. In vineyards, a lower use of insecticides was observed in small fields or landscapes composed of a high proportion of woodlands, while in orchards a lower local use of insecticides was found in landscapes with a high share of organic orchards. Fungicide use was mainly affected by the weather context in both apple orchards and vineyards, with more fungicide use in humid and warm weather. However, effects of vineyard size and grassland proportion on the date of the first spray suggest that these two variables may impact pathogen spatial dynamics, a topic that needs further investigations. SIGNIFICANCELandscape-scale management options highlighted in our study may contribute to the design of functional agricultural landscapes minimising pesticide use.