Resumo

ALVAREZ-RODRIGUEZ, Brando et al. Sensitivity to metalaxyl and pathogenic potential of Phytophthora hydropathica isolated from irrigation canals of the Valley of Culiacán. Rev. Mex. Cienc. Agríc [online]. 2018, vol.9, n.6, pp.1149-1157. ISSN 2007-0934.  https://doi.org/10.29312/remexca.v9i6.1580.

Phytopthora hydropathica is a species with few reports related to its ability to infect agricultural crops in a natural way, so it can be inferred that it has not been in contact with chemical agents; therefore, the objective of this study was to determine the pathogenicity and sensitivity to metalaxyl of 18 strains of P. hydropathica from irrigation canals in Culiacán, Sinaloa. The pathogenicity evaluation of the isolates was carried out on zucchini and cucumber leaves and on zucchini, cucumber and tomato fruits. Resistance to metalaxyl was evaluated in vitro in PDA medium added with metalaxyl. The isolates of P. hydropathica caused symptoms of necrosis and softening in fruits and symptoms of leaf necrosis of the evaluated plant species; no resistant strains were found, seven strains showed intermediate sensitivity and the rest were susceptible to metalaxyl. The CE50 of the isolates ranged from 0.000013 μg L-1 to 1 μg L-1. It can be concluded that the use of metalaxyl would be effective in controlling some disease outbreak caused by P. hydropathica.

Palavras-chave : Phytophthora hydropathica; CE₅₀; Oomycetes; Ridomil Gold.

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