Asma Nour Elhouda Belagoune, Assia Allaoui, Douaa Amireche, Saber Beghoul, Kahina Hafid, Karina Bachtarzi

The crop of Phaseolus vulgaris L. is one of the main sources of income for small-scale farmers in Ecuador. However, yields are affected by diseases such as common bean wilt, caused by the fungus Sclerotium rolfsii Sacc. Therefore, sustainable biocontrol alternatives are being sought to reduce the use of fungicides. The main objective of this study was to evaluate the effect of Bacillus sp. on the mycelial growth of Sclerotium rolfsii under in vitro conditions in the Molecular Biology Laboratory of ESPAM MFL. Thirty-five isolates of Bacillus sp. were used in dual culture with S. rolfsii. The percentage of mycelial growth inhibition was evaluated at 24, 48, and 72 hours. The Kruskal-Wallis non-parametric test was used to detect differences between treatments, and Dunn's post-hoc tests (p<0.05) with Bonferroni correction were performed. When comparing the inhibition capacity of Bacillus sp., the best treatments were ECA-83, ECA-58, and ECA-106, with inhibition percentages greater than 83 %, followed by ECA-45, ECA-56, and ECA-90, which inhibit the growth of S. rolfsii with median inhibition rates greater than 67 % at 72 hours of incubation. These treatments have good potential for controlling the growth of S. rolfsii, thus promoting the development of sustainable agriculture in Ecuador.