Patogenicidade de Alternaria helianthi (Hansf.) e Alternaria zinniae (Pape) ao girassol a partir de sementes

the effects of alternaria helianthi and alternaria zinniae on the initial development of the sunflower were investigated under controlled conditions from inoculated seeds and 10 day old plants. inoculated plants with a. helianthi spore suspension produced a high index of disease with reduction in stand, fresh weight and plant height. similar results were obtained in the assay on inoculation of seeds and sunflower plants with alternaria zinniae. the high index of this disease also induced the reduction of stand, fresh weight and plant height.