The objective of this study was to evaluate the effect of rhizobacteria metabolites on Colletotrichum gloeosporioides spores germination and to confirm their antifungic activity against the buttery spot disease in coffee seedlings. In vitro bioassays, carried out with 42 rhizobacteria filtrates, allowed the identification of filtrates able to completely inhibit the spore germination. Coffee seedlings were inoculated with Colletotrichum and sprayed with four of the most promising filtrates. The treatments were organized in a 4x4+2 factorial scheme, combining the application of the four filtrates with four procedures of Colletotrichum inoculation (inoculation absence, inoculation two days before, together, or two days after the filtrates application). A check treatment (1) without filtrate or pathogen and other check (2) that received only the pathogen inoculation constituted the additional treatments. After 35 days, the vegetative growth of the seedlings and the severity of the buttery spot were assessed. All four filtrates showed similar effectiveness in the control of the buttery spot. The disease control was partial (35%). The filtrates application was harmful to coffee growth, providing less dry matter production in relation to the check treatment (1).
Buttery spot; biocontrol; antibiosis; fungic disease; natural substances
