Herbicide-resistant weeds in Greek rice cultivation systems: A Review of the status, drivers, and Integrated Management Implications

Herbicide resistance has emerged as a major constraint to sustainable rice (Oryza sativa L.) production in Greece, where intensive water-seeded monoculture systems rely heavily on chemical weed control. This review synthesizes current knowledge on rice production systems, herbicide use patterns, and the evolution of herbicide-resistant weeds in Greek agroecosystems. Rice cultivation is concentrated in northern Greece under flooded conditions that favor the proliferation and persistence of competitive weed species. The dominant resistant weeds include Echinochloa spp., Cyperus difformis, weedy rice (red rice) and Leptochloa fusca subsp. fascicularis. Resistance has been documented to multiple herbicide modes of action, including propanil, acetolactate synthase (ALS) inhibitors, acetyl-CoA carboxylase (ACCase) inhibitors, synthetic auxins, and glyphosate, with increasing occurrence of cross- and multiple-resistant biotypes. Resistance evolution is driven by prolonged herbicide reliance, continuous monoculture, seedbank persistence, and dispersal through irrigation networks. The review further evaluates species-specific resistance mechanisms and highlights integrated weed management strategies based on preventive, tactical, and long-term Best Management Practices. This baseline assessment provides a consolidated reference for researchers, advisors, and policy-makers and supports the development of coordinated resistance management frameworks aligned with EU Integrated Pest Management principles and the specific challenges of Greek rice production.