Simplified screening method of fungicides against the black rot of sweet potato, Ceratocystis fimbriata (Ellis et Halsted) Elliot, using sweet potato slices

Abstract

Sweet potato slices, 7-10mm thick, were dipped in suspension of wettable powder at room temperature for 15-20 minutes, and then inoculated with filter paper discs (5mm dia.) containing black rot spores.
In case of less effective fungicides, colonies of C. fimbriata developed in 3-6 days under the condition of 25°C and high humidity. But, no colonies developed on sweet potato slices treated with Benlate, methyl-l-(butyl-carbamoyl)-2-benzimidazole carbamate, at the concentration of 0.1 %.
In the field test as well as in this screening, Benlate was the most effective.
This simplified method will be practical for screening of fungicides to control the black rot of sweet potato.