Sati S.C., Gashyal Koranga A., Pant P. & Khulbe K. (2025) Phosphate and potassium release dynamics of two root endophytic hyphomycetes from Kumaun Himalaya, India. - Sydowia 77: 291-301. Two root endophytic aquatic hyphomycetes, viz. Flagellospora penicillioides and Varicosporium elodeae, isolated from the roots of Ageratina adenophora and Eurya acuminata growing in ravine areas of Kumaun Himalayan region, Uttarakhand (India), were assessed for their phosphate and potassium solubilization efficiency in vitro. The quantitative evaluation of phosphate and potassium solubilization was carried out using spectrophotometric analysis by growing them on Pikovskaya and Aleksandrov broth mediums. Simultaneously, the pH value and mycelial-dry-weight were also measured at intervals of 7, 14, and 21 days after inoculation. The P and K solubilization efficiency of F. penicillioides and V. elodeae showed the maximum solubilization 21days after inoculation (1.186 mg P/l and 66.484 mg K/l as well as 0.877 mg P/l and 58.309 mg K/l, respectively). A subsequent increment in mycelial weight and a gradual decrease in pH with a growing incubation period were also recorded in the respective broth cultures by both fungal isolates. The isolated fungal strains were found to be potent phosphate and potassium solubilizers which can be used as biofertilizers for sustainable agricultural practices. To the best of our knowledge the present work is the first report on F. penicillioides and V. elodeae as P and K solubilizer.