Pseudocercospora griseola, the causal agent of common bean angular leaf spot: Strain characterization and sensitivity to fungicides. (31st March 2022)

• Record Type: Journal Article
• Authors: Librelon, Samira Santiago; Pereira, Fernanda Aparecida Castro; de Pádua, Paula Furtado; Pereira, Nathália Bottrel Maia; Gomes, Luanna de Barros Wanderley; Pereira, Rafael; Pereira, Lucas Fidelis; Pozza, Edson Ampélio; de Souza, Elaine Aparecida
• Is Part Of: Plant pathology. Volume 71:Number 6(2022)
• Page Start: 1431
• Page End: 1439
• Publication Date: 2022-03-31
• Subjects: genetic variability -- in vitro assays -- Phaseolus vulgaris -- phytopathogenic fungi -- plant resistance; Agricultural pests -- Periodicals; Plant diseases -- Periodicals; 632
• DOI: 10.1111/ppa.13556
• Languages: English
• ISSNs: 0032-0862

Abstract

Abstract: Angular leaf spot (ALS), an important disease of common bean ( Phaseolus vulgaris ), is caused by the fungus Pseudocercospora griseola . This pathogen has a wide genetic variability and, therefore, poses a challenge to integrated disease management. The use of resistant cultivars is difficult; hence, the application of fungicides has been a common practice in common bean cultivation. P. griseola strains were morphophysiologically characterized and their sensitivity to common fungicides used to control ALS was studied. The strains were evaluated for sporulation capacity and a representative sample of 34 strains was bioassayed to determine their sensitivity to commercial concentrations of five fungicides, namely pyraclostrobin, mancozeb, pyraclostrobin + metconazole, chlorothalonil and tebuconazole. Another sample of 29 strains was studied for conidial germination and dimensions. Sporulation capacity ranged from 0.88 to 27.67 × 10 4 conidia/ml and germination percentage ranged from 39% to 72%. The large differences among strains suggest a wide genetic variability among the strains. A wide variability in aggressiveness of P . griseola was observed, which has consequences for breeding programmes aimed at resistance. The behaviour of pathogen strains differed in every fungicide evaluated, even in a population that has not been under selection pressure in the field. These results confirm the need for further studies and may guide future research with this pathogen. Abstract : The wide phenotypic variability of Pseudocercospora griseola observed has consequences for breeding programmes aiming for resistance. Moreover, the behaviour of strains differed for every fungicide evaluated.