Eficiência de formulações de ulvana em induzir resistência em Phaseolus vulgaris contra Colletotrichum lindemuthianum

Abstract

The present work aimed to evaluate the effectiveness of ulvan, an algal polysaccharide, in inducing resistance of Phaseolus vulgaris against Colletotrichum lindemuthianum when formulated alone or with kaolinite, amorphous silica or attapulgite, and stored for 0, 4, 8, or 12 months. Following each storage period, the formulations and a water control were applied to the foliage of bean plants (cv. Uirapuru, growth stage V4) at 6 days, and again at 3 days, before the foliage was inoculated with C. lindemuthianum. Anthracnose severity was estimated at intervals of 2 days, beginning when the first symptoms appeared and continuing until 13 days after inoculation. The severity data were used to calculate values for Area Under the Disease Progress Curve (AUDPC). The application of ulvan (control) or its formulations with amorphous silica or kaolinite reduced anthracnose severity by 45%. The efficiency of ulvan in controlling anthracnose was maintained throughout 12 months of storage when it was formulated with amorphous silica or kaolinite, but not with attapulgite. © the Brazilian Phytopathological Society.