Decision support systems halve fungicide use compared to calendar-based strategies without increasing disease risk

Elena Lázaro,Antonio Vicent,David Makowski

doi:10.1038/s43247-021-00291-8

Abstract

The European Green Deal aims to reduce the use of chemical pesticides by half by 2030. Decision support systems are tools to help farmers schedule fungicide spraying based on disease risk and can reduce fungicide application frequency and overall use. However, the potential benefit of decision support systems compared to traditional calendar-based strategies has not yet been rigorously quantified. Here we synthesise 80 experiments and show that globally decision support systems can reduce fungicide treatments by at least 50% without compromising disease control. For a given fixed number of fungicide sprays, decision support systems were as effective as calendar-based programs in reducing disease incidence. When the number of sprays was halved, the increase in disease incidence was lower for decision support system-based strategies than calendar-based strategies. Our findings suggest that decision support systems can reduce fungicide use while limiting the risk to plant health and resistance development.

Highlights

The European Green Deal aims to reduce the use of chemical pesticides by half by 2030
The willingness to reduce the use of pesticides and especially fungicides was again highlighted in the ‘from farm to fork’ strategy of the European Green Deal, which targets a reduction in the use of chemical pesticides by half by 203011
The dataset includes a total of 328 disease incidence data items collected for 80 untreated controls, 99 calendar-based strategies, and 149 Decision support systems (DSSs)-based strategies (Supplementary Table S1)

Summary

Introduction

The European Green Deal aims to reduce the use of chemical pesticides by half by 2030. To promote more sustainable agricultural systems, EU Directive 2009/128/EC established several key principles to reduce pesticide use, fostering the adoption of prevention measures, nonchemical control methods, and chemical compounds with lower environmental impacts According to this Directive, any control intervention should in principle be based on field monitoring and trigger thresholds in order to reduce doses and treatment frequencies, limiting the risk of the development of pathogen resistance. To date, the whole set of data obtained in these experiments has not been compiled and subjected to rigorous statistical analysis to quantify the benefits resulting from the use of DSSs. Our meta-analysis of 80 independent experiments conducted worldwide indicated that, for a given fixed number of fungicide sprays, DSSs were as effective as calendar-based programs (or more so) in reducing disease incidence for a wide range of crop species, fungal pathogens, types of fungicide and regions. When the number of sprays was halved, the resulting increase in disease incidence was greatly mitigated with a strategy based on DSSs rather than on calendars

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