Pesticides in agricultural ecosystems: reconciling economic sustainability with environmental toxicity and agricultural chain resilience

Synthetic pesticides remain the dominant curative technology of global crop protection, yet the terms on which they are justified, chiefly private profitability at the farm gate, increasingly diverge from the terms on which society evaluates them: ecosystem integrity, water quality, pollinator persistence, soil function and rural health. This structured narrative review synthesises evidence published predominantly between 2020 and 2026 to examine how pesticide toxicity propagates through agroecosystems and how those ecotoxicological burdens feed back into the economic sustainability of farming. We argue that the conventional “trade-off” framing between yield protection and environmental harm is incomplete, because much pesticide-associated damage, including the erosion of natural pest regulation, loss of pollination, soil biological degradation and resistance evolution, simultaneously reduces the future productivity of the input itself. The review traces pesticide movement through soil, water and air; evaluates community-level effects on soil biota, pollinators and aquatic and vertebrate taxa; examines the mechanisms underlying sublethal harm; and distinguishes private, hidden and external costs. Case material from Brazil, India, China, Kenya, Sri Lanka, the European Union, Australia and the United States grounds general claims in specific contexts. Three findings recur: harm is expressed predominantly through sublethal and community-level pathways rather than acute mortality; toxicity-weighted pressure has risen even where mass-based indicators decline; and a substantial share of current application appears agronomically unnecessary. Where evidence is variable, we say so explicitly, distinguishing established findings from emerging hypotheses. We conclude that pesticide governance should shift from single-substance, single-species risk assessment toward community-level and functional endpoints, and from mass-based reduction targets toward toxicity-weighted indicators coupled to instruments that internalise external costs and to agronomic redesign that lowers the demand for curative chemistry.