Chiang Mai Journal of Science

     Soil is an important non-aqueous habitat for algae. Algal mats, a type of microbial mat, often on the surface of soil. These mats can become a significant ecological problem if they grow too large or thick, potentially disrupting underground life by blocking sunlight or producing toxic compounds. Fungi may serve as affective biological control agents against such harmful algae. In this study, fungi were isolated from the larvae of a biting midge, Forcipomyia taiwana, which feeds primarily on algae. These fungal isolates were evaluated for their anti-algal acti vity against Coelastrella and Desmodesmus species. Here, we reported two fungal isolates, Vishniacozyma victoriae strain JYC1105 and Kwoniella pini strain JYC1032, were capable of inhibiting algal growth when treated with their cell-free supernatant. Both fungal strains exhibited strong algicidal activity, achieving over 99% inhibition of algal growth within three days, even when the supernatant was diluted to one-tenth of its original concentration. Algal cell death was assessed by direct cell counts and SYTOX Green staining, revealing inhibitory effects within just half a day. These results highlight the potential of these fungal metabolites as rapid and effective biocontrol agents against nuisance algae in terrestrial environments.