Davinia Bellón-Gómez1, David Vela-Corcía2, Alejandro Pérez-García2, Juan A Torés1. 1. Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Estación Experimental 'La Mayora', Algarrobo-Costa, Málaga, Spain. 2. Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' - Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Departamento de Microbiología, Universidad de Málaga, Málaga, Spain.
Abstract
BACKGROUND: Cucurbit powdery mildew caused by Podosphaera xanthii limits crop production in Spain, where disease control is largely dependent on fungicides. In previous studies, high levels of resistance to QoI and DMI fungicides were documented in south-central Spain. The aim of this study was to investigate the sensitivity of P. xanthii populations to other fungicides and to provide tools for improved disease management. RESULTS: Using a leaf-disc assay, sensitivity to thiophanate-methyl, bupirimate and quinoxyfen of 50 isolates of P. xanthii was analysed to determine discriminatory concentrations between sensitive and resistant isolates. With the exception of thiophanate-methyl, no clearly different groups of isolates could be identified, and as a result, discriminatory concentrations were established on the basis of the maximum fungicide field application rate. Subsequently, a survey of P. xanthii resistance to these fungicides was carried out by testing a collection of 237 isolates obtained during the 2002-2011 cucurbit growing seasons. This analysis revealed very high levels of resistance to thiophanate-methyl (95%). By contrast, no resistance to bupirimate and quinoxyfen was found. CONCLUSION: Results suggest that thiophanate-methyl has become completely ineffective for controlling cucurbit powdery mildew in Spain. By contrast, bupirimate and quinoxyfen remain as very effective tools for cucurbit powdery mildew management.
BACKGROUND: Cucurbit powdery mildew caused by Podosphaera xanthii limits crop production in Spain, where disease control is largely dependent on fungicides. In previous studies, high levels of resistance to QoI and DMI fungicides were documented in south-central Spain. The aim of this study was to investigate the sensitivity of P. xanthii populations to other fungicides and to provide tools for improved disease management. RESULTS: Using a leaf-disc assay, sensitivity to thiophanate-methyl, bupirimate and quinoxyfen of 50 isolates of P. xanthii was analysed to determine discriminatory concentrations between sensitive and resistant isolates. With the exception of thiophanate-methyl, no clearly different groups of isolates could be identified, and as a result, discriminatory concentrations were established on the basis of the maximum fungicide field application rate. Subsequently, a survey of P. xanthii resistance to these fungicides was carried out by testing a collection of 237 isolates obtained during the 2002-2011 cucurbit growing seasons. This analysis revealed very high levels of resistance to thiophanate-methyl (95%). By contrast, no resistance to bupirimate and quinoxyfen was found. CONCLUSION: Results suggest that thiophanate-methyl has become completely ineffective for controlling cucurbit powdery mildew in Spain. By contrast, bupirimate and quinoxyfen remain as very effective tools for cucurbit powdery mildew management.
Authors: Jesús Cámara-Almirón; Yurena Navarro; Luis Díaz-Martínez; María Concepción Magno-Pérez-Bryan; Carlos Molina-Santiago; John R Pearson; Antonio de Vicente; Alejandro Pérez-García; Diego Romero Journal: Nat Commun Date: 2020-04-20 Impact factor: 14.919
Authors: Eleonora Barilli; Francisco J Agudo; Marco Masi; Paola Nocera; Antonio Evidente; Diego Rubiales Journal: Pest Manag Sci Date: 2022-06-10 Impact factor: 4.462