Control of crown rot with potassium carbonate in banana cv. Enano Gigante

The postharvest antifungal activity of potassium carbonate (PC) against crown rot (CR) was investigated in banana cv. Enano Gigante by artificially inoculating with Colletotrichum musae (Cm) and incubating at 25 +/- 1(degrees)C for 7 days. PC treatments were tested by in vitro and in vivo primary experiments. The in vivo preliminary concentration of 175 mM PC was selected as the most effective and was used in subsequent experiments on the influence of dip temperature on the effectiveness of PC. Curative dip treatments of 175 mM PC at 40(degrees)C for 20 min applied alone or combined with low doses of thiabendazole (TBZ) were evaluated on CR. Finally, the effect of PC on banana fruit quality was determined. PC at 150 and 200 mM totally inhibited mycelial growth and conidial germination of Cm. In in vivo primary experiments, 175 mM PC significantly reduced both the incidence (33.3% reduction) and the severity (90.5% reduction) of CR, but only in curative treatments. When the 175 mM PC dip for 20 min was tested at different temperatures, the curative dip at 40(degrees)C was the most effective, reducing CR incidence and severity by 91.6% and 98.8%, respectively, and was used for subsequent experiments. PC combined with TBZ at 225 mu L L-1 did not improve the curative control effectiveness on CR compared to PC alone. PC did not affect the quality of banana fruit.