Framework for Function-Based Pesticide Substitution

Agricultural pesticides can harm humans and the environment, with many current-use pesticides being highly hazardous. Substituting hazardous pesticides with less impactful alternatives comes with challenges related to systematically matching crops, pests, and pesticides, considering regulations, equal efficacy, and combining pesticides to collectively control a wider set of pests across critical crop stages. We propose a quantitative framework to define and assess functionally equivalent scenarios for substituting hazardous pesticides in real-life agricultural applications to reduce human and ecosystem health impacts. Testing our framework on pesticide use in Thailand highlights that particularly hazardous pesticides are applied to certain crops (e.g., tomato, <i>Brassica</i> vegetables) and pests (e.g., tomato leaf miner flies, different thrips species). We found that the number of scenarios combining different pesticides is not an indicator of the variability in scenario impacts: some crop-pest class (e.g., insects) pairs with >10,000 possible scenarios of pesticide combinations vary less in impact performance than some pairs with fewer scenarios. For each crop-pest class pair, we recommend the 10% best-in-class impact performance scenarios for substituting more hazardous scenarios. Our framework can inform policymakers to identify hazardous pesticides for phase out, support ambitions of UNEP's Global Framework on Chemicals, and aid farmers to reduce their pesticide-related chemical footprint.