In an attempt to develop new microbial fungicides using endophytic fungi, a total of 152 isolates were obtained from 67 healthy tissue samples of vegetable plants. After they were incubated in potato dextrose broth medium, their antifungal activities were screened by in vivo bioassays against Botrytis cinerea(tomato gray mold), Pythium ultimum(cucumber damping-off), Phytophthora infestans(tomato late blight), Colletotrichum orbiculare(cucumber anthracnose) and Blumeria graminis f. sp. hordei (barley powdery mildew)(1) As the results of screening, 23 fungi strains showed potent antifungal activities more than 90% against tomato late blight. After liquid cultures of these strains were diluted 3 and 9 times, their antifungal activities were rescreened against tomato late blight. As the results, EF119 strain showed the most potent antifungal activity against tomato late blight. A fungus strain EF119 obtained from red pepper roots was identified as Fusarium oxysporum based on its morphological and physiological characteristics and ribosomal ITS1-5.8S-ITS2 gene sequence.(2) F. oxysporum EF119 was the most active, showing 95%, 90% and 57% control values at doses of 10-fold 50-fold and 100-fold dilutions of the liquid culture, respectively. In dual-culture tests, it inhibited the mycelial growth of C. coccodes, P. infestans, P. ultimum and P. capsici. In addition, F. oxysporum EF119 suppressed the development of Fuarium wilt of tomato and Phytophthora bligth of red pepper.(3) Two antifungal substances were isolated from the PDB cultures of F. oxysporum EF119 strain by ethyl acetate partitioning, Silica gel column chromatography, Sephadex LH-20 column chromatography, and prep-HPLC and then their chemical structures were identified as bikaverin and fusaric acid by mass and NMR spectral analyses.(4) Bikaverin and fusaric acid inhibited the mycelial growth of P. infestans, P. capsici, R. solani, A. brassicicola, M. grisea and C. coccodes. However, the two compounds were not active to the mycelial growth of F. oxysporum and B. cinerea. Vacuolation, a symptom of ageing, was induced in the hyphal tips of C. coccodes, P. infestans and P. capsici treated with bikaverin. In addition, bikaverin also suppressed the zoosporangial germination of P. infestans.(5) Bikaverin inhibited weakly bacterial growth of various phytopathogeneic bacteria in vitro whereas fusaric acid displayed potent antibacterial activity; it completely suppressed the growth of all of the bacteria tested at a range of 11.1~100 ㎍/㎖.(6) Bikaverin and fusaric acid suppressed moderately or effectively the development of tomato late blight, wheat leaf rust and red pepper anthracnose. Both compound suppressed synergistically the development of the three plant diseases.