Manejo alternativo da ferrugem da aveia branca: eficiência de produtos biológicos e naturais

Abstract

Oat leaf rust is one of the most important diseases affecting white oat crops, especially in organic management systems. The use of tolerant cultivars is one of the main tools currently available for disease management. However, when climatic conditions favor the pathogen and inoculum is present, the use of effective control products becomes essential. In organic farming, there are limitations regarding the products allowed by regulations, and there is also a lack of technical information on the recommended inputs for this pathosystem. Therefore, studying the effectiveness of permitted products under field conditions is necessary to provide support for producers and technical assistance professionals.This study aimed to evaluate the effectiveness of controlling white oat leaf rust using products allowed in organic production and their impact on production parameters. The experiment was conducted at the experimental farm of the Federal Technological University of Paraná (UTFPR) – Dois Vizinhos Campus, during the 2023 growing season. Nine treatments were evaluated, including a control (without application), a chemical treatment with a synthetic fungicide (used as a reference for the efficacy of alternative treatments), and seven treatments containing biological agents, natural products, and their combinations. Four applications were performed at 12 to 15-day intervals, starting at the tillering stage, using 160 L ha⁻¹. Disease severity was assessed after flag leaf emergence using a diagrammatic scale, and at the end of the crop cycle, productivity-related componentes were measured. The use of a systemic fungicide was the most effective in reducing leaf rust severity, increasing plant height, thousand-grain weight, and grain yield. Among the alternative treatments, the combination of a Bacillus subtilis-based product with organic peroxide resulted in the greatest reduction in disease severity, taller plants, higher thousand-grain weight, and improved grain yield compared to the other treatments.