Phomalactone is a fungal metabolite that has been found in N. sphaerica and has fungicidal activity.1,2 It is active against strains of the plant pathogenic fungi C. sasaki, P. graminicola, M. griesea, P. capsica, and P. infestans (IC50s = 200, 120, 83, 120, and 0.83 mg/L, respectively), but not F. oxysporum, A. alternate, B. cinerea, or C. gloeosporioides (IC50s = >200 mg/L for all).1 Phomalactone is also active against the plant pathogenic fungi A. niger and O. minus (MICs = 62.5 and 125 μg/ml, respectively).2

|1. Kim, J.-C., Choi, G.J., Park, J.-H., et al. Activity against plant pathogenic fungi of phomalactone isolated from Nigrospora sphaerica. Pest Manag. Sci. 57(6), 554-559 (2001).|2. Wu, S.-H., Chen, Y.-W., Shao, S.-C., et al. Two new solanapyrone analogues from the endophytic fungus Nigrospora sp. YB-141 of Azadirachta indica. Chem. Biodivers. 6(1), 79-85 (2009).