Abstract
ABSTRACT Target spot, caused by the fungus Corynespora cassiicola, occurs endemically in Amazonas State, leading to reduced production in several crops. This study evaluated the pathogenicity of C. cassiicola isolates in tomato, eggplant and papaya. Isolates were obtained from crop areas in the cities of Manaus, Iranduba and Presidente Figueiredo in Amazonas State. The disease severity was assessed, as well as the number and the diameter of lesions. Experimental design was completely randomized in a factorial arrangement of 9x3x3 (9 isolates, 3 areas and 3 hosts) and 3 replicates. Papaya isolates caused symptoms in all evaluated plant species, and a certain degree of specificity was demonstrated for eggplant and tomato isolates, which did not cause disease in papaya. Severity was higher in tomato plants. The isolates obtained from Iranduba were most aggressive, suggesting that the geographic origin influenced the aggressiveness of isolates.
Highlights
A mancha-alvo, causada pelo fungo Corynespora cassiicola, ocorre de forma endêmica no estado do Amazonas, levando à redução na produção em diversas culturas
Pathogenicity tests, i.e. inoculations in several hosts to characterize the isolates according to the pathogenicity, allow identifying both the range of the pathogen’s host species and the presence of host specificity, which were already done for C. cassiicola [1,7]
Disease severity was assessed according to the adapted Horsfall & Barrat scale [5], where: 0: no symptoms; 1: 50% LAA
Summary
A mancha-alvo, causada pelo fungo Corynespora cassiicola, ocorre de forma endêmica no estado do Amazonas, levando à redução na produção em diversas culturas. In the north of the country, tomato yield is usually made by small holders in areas that already contain other crops such as cucumber, peppers, eggplant and papaya, which are host plants of C. cassiicola. The aim of this study was to evaluate the pathogenicity of different isolates of C. cassiicola in tomato, papaya and eggplant.
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