Publicação
Comparative effectiveness of fungicides against Stemphylium and Alternaria spp. Iisolated from Portuguese rocha pear orchards
| Resumo: | The Portuguese Rocha pear (Pyrus communis L. cv Rocha) production is facing significant losses due to brown spot disease (BSP), caused by the fungal pathogen Stemphylium vesicarium [1]. Nevertheless, our recent research has revealed a concerning prevalence of Alternaria spp. on both symptomatic and asymptomatic leaves and pears, indicating that both fungi may contribute to this problem. The latter genus includes wellknown mycotoxin producers and climate change may increase its prevalence [2]. Despite the growing resistance to fungal pathogens, synthetic fungicides remain a commonly employed method for managing BSP in Portuguese orchards [3]. This study set out to evaluate the effectiveness of the synthetic fungicides used by Rocha pear growers in combating BSP disease, particularly against S. vesicarium and Alternaria spp. To assess efficacy, sixteen fungicides were tested by measuring their ability to inhibit mycelial growth in ten strains of S. vesicarium and ten strains of Alternaria spp. These strains were isolated from both symptomatic and asymptomatic leaves and pears, with molecular identification confirmed. The evaluation was performed on potato dextrose agar medium over a period of 4 days at 25 °C, utilizing fungicide concentration that corresponded to the recommended application dose for field use. The findings revealed that the efficacy of the synthetic fungicides varied depending on the active ingredient, fungal species and specific strain involved. Among the sixteen fungicides evaluated, fludioxonil-based fungicide demonstrated the highest effectiveness against both Alternaria and Stemphylium vesicarium isolates. In contrast, the fungicides with trifloxystrobin and kresoxim-methyl exhibited the lowest growth inhibition across all twenty strains assessed. Additionally, fungicides with the active ingredient fluxapyroxad and pyrimethanil showed greater antifungal activity against Stemphylium compared to Alternaria strains. Notably, no significant differences were found between isolates from symptomatic and asymptomatic materials. The practical implications of this research are significant for Rocha pear growers, as the results underscore the importance of selecting appropriate fungicides for managing BSP disease. This information serves as a valuable resource for optimizing fungicide applications and safeguarding Rocha pear production in Portuguese orchards. |
|---|---|
| Autores principais: | Mendonça, Inês |
| Outros Autores: | Leão, Miguel; Venâncio, Armando; Silva, Sónia Carina |
| Assunto: | Stemphylium Alternaria spp. Portuguese rocha pear Fungicides |
| Ano: | 2025 |
| País: | Portugal |
| Tipo de documento: | outro |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | The Portuguese Rocha pear (Pyrus communis L. cv Rocha) production is facing significant losses due to brown spot disease (BSP), caused by the fungal pathogen Stemphylium vesicarium [1]. Nevertheless, our recent research has revealed a concerning prevalence of Alternaria spp. on both symptomatic and asymptomatic leaves and pears, indicating that both fungi may contribute to this problem. The latter genus includes wellknown mycotoxin producers and climate change may increase its prevalence [2]. Despite the growing resistance to fungal pathogens, synthetic fungicides remain a commonly employed method for managing BSP in Portuguese orchards [3]. This study set out to evaluate the effectiveness of the synthetic fungicides used by Rocha pear growers in combating BSP disease, particularly against S. vesicarium and Alternaria spp. To assess efficacy, sixteen fungicides were tested by measuring their ability to inhibit mycelial growth in ten strains of S. vesicarium and ten strains of Alternaria spp. These strains were isolated from both symptomatic and asymptomatic leaves and pears, with molecular identification confirmed. The evaluation was performed on potato dextrose agar medium over a period of 4 days at 25 °C, utilizing fungicide concentration that corresponded to the recommended application dose for field use. The findings revealed that the efficacy of the synthetic fungicides varied depending on the active ingredient, fungal species and specific strain involved. Among the sixteen fungicides evaluated, fludioxonil-based fungicide demonstrated the highest effectiveness against both Alternaria and Stemphylium vesicarium isolates. In contrast, the fungicides with trifloxystrobin and kresoxim-methyl exhibited the lowest growth inhibition across all twenty strains assessed. Additionally, fungicides with the active ingredient fluxapyroxad and pyrimethanil showed greater antifungal activity against Stemphylium compared to Alternaria strains. Notably, no significant differences were found between isolates from symptomatic and asymptomatic materials. The practical implications of this research are significant for Rocha pear growers, as the results underscore the importance of selecting appropriate fungicides for managing BSP disease. This information serves as a valuable resource for optimizing fungicide applications and safeguarding Rocha pear production in Portuguese orchards. |
|---|
Atividades financiadas
Carregando projetos financiados...