Abstract

Anthracnose, caused by Colletotrichum capsici, is a major disease impacting chili plants (Capsicum annum L.) and resulting in significant yield losses globally. This study was aimed at evaluating the in vitro antifungal activity of compost tea, inorganic salts (potassium phosphate and potassium bicarbonate), and their combinations against C. capsici, as well as their practical application under field conditions. Compost tea was prepared at different ratios (1:5, 1:10, 1:15 and 1:20), and their colony-forming units (CFU) were determined. The in vitro antifungal activity of compost tea, inorganic salts and their combinations were assessed using the poison food technique. The potential of the applied treatments to reduce disease severity on inoculated chili leaves was also evaluated. The results showed that compost tea at all the tested ratios contained CFU counts ranging from 7.17 × 10¹0 to 2.22 × 10¹¹ and completely inhibited C. capsici in vitro. Potassium phosphate at concentrations of 0.5 to 1.5% achieved 74.07 to 74.44% fungal inhibitions, while potassium bicarbonate at concentrations of 0.5 to 1.5% showed 70.28 to 77.41% fungal inhibition. Combinations of compost tea with 1.5% inorganic salts exhibited fungal inhibition ranging from 66.30 to 100%. At field, compost tea demonstrated significantly lowest disease severity, 0 to 2.44% on inoculated chili leaves. Inorganic salts provided moderate control, 22.44 to 34.44% disease severity, and combinations of compost tea with inorganic salts showed varied effectiveness, 12.89 to 50.67% disease severity. The study concludes that compost tea and inorganic salts are effective in managing anthracnose which highlights their potential in sustainable plant disease management strategies.