Resistência a fungicidas e caracterização filogenética de Corynespora cassiicola (Berk. & Curt.) C.T. Wei no Amazonas, Brasil

Abstract

Corynespora cassiicola, a phytopathogenic fungus with a wide range of host species, poses a threat to the productivity of various economically important crops in tropical environments. In the Amazonas state, it is the causative agent of the target spot disease in solanaceous, cucurbit, and other economically significant vegetables in agricultural production systems. The objective of this study was to evaluate the potential fungicide resistance of C. cassiicola collected from agricultural areas in the Amazonas state through in vitro colony growth inhibition assays using different concentrations of azoxystrobin, boscalid, Carbendazim, and Tebuconazole. Additionally, the effect of these fungicides on the control of target spot in tomato plants was investigated by inoculating the pathogen and applying the products under greenhouse conditions. Furthermore, the diversity of fungal lineages was characterized through phylogenetic inference. Although the products were able to significantly reduce the severity of target spot in tomato plants, the C. cassiicola isolates demonstrated high resistance to all tested fungicides in in vitro resistance assays. Phylogenetic analysis revealed the existence of at least two lineages of C. cassiicola in the Amazonas state, which were correlated with the PL1 and PL4 lineages identified in reference sequences in the literature.