Pyrenocine A is a fungal metabolite that has been found in P. terrestris and has diverse biological activities. It inhibits the asexual spore germination of the plant pathogenic fungi F. oxysporum, F. solani, M. hiemalis, and R. stolonifer (EC50s = 14, 20, 20, and 25 μg/ml, respectively). Pyrenocine A is active against B. subtilis, S. aureus, and E. coli (IC50s = 30, 45, and 200 μg/ml, respectively). It inhibits onion seedling elongation (EC50 = 4 μg/ml). Pyrenocine A is also a phytotoxin that inhibits lettuce seed germination and rice seedling elongation.