Plantas de cobertura de solo como hospedeiras alternativas de Colletotrichum guaranicola

Abstract

Cover crops used to suppress weed growth can be intermediate hosts to phytopathogenic fungi. To test this hypothesis, nine species of cover crops were evaluated as hosts to Colletotrichum guaranicola. The experiment was arranged in a randomized design, with four replicates, and conducted under greenhouse conditions. Each vase with three plants of one species constituted one plot. The species treated were: Arachis pintoi, Calopogonium mucunoides, Chamaecrista rotundifolia, Crotalaria striata, Desmodium ovalifolium, Flemingia congesta, Mucuna aterrima, Pueraria phaseoloides and Tephrosia candida. Forty days after sowing, the plants were inoculated with spores of C. guaranicola at a concentration of105 conidia/mL, while the control plants received only water. The plants were then kept in a humid chamber for 48 hours. Daily observations were made to search for symptoms during 15 days after inoculation. The species that did not present symptoms of C. guaranicola were Arachis pintoi, Chamaecrista rotundifolia, Desmodium ovalifolium, Flemingia congesta and Tephrosia candida and those that did were Calopogonium mucunoides, Crotalaria striata, Mucuna aterrima and Pueraria phaseoloides, being a potential source of inoculation of the pathogen anthracnose for the guarana plant.