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Inhibitory effects of different Phytolacca americana L. extracts on Pestalotiopsis microspora, a fungal pathogen isolated from blueberry leaf spot, were determined by a growth rate method. Effects of P. americana extracts from different tissues (leaves, roots, stems) obtained with five different solvents on inhibitory rates of P. microspora were determined by measuring fungal growth. Ethanol and acetone P. americana extracts clearly inhibited growth of the fungal pathogen, and inhibition rate was positively correlated with treatment concentration. Inhibitory effects of ethanol extracts were significantly greater than those of the acetone extracts, and the optimal inhibitory effect (Using EC 50 to express the median lethal concentration) was at 0.004 g mL–1. Water, petroleum ether, and benzene extracts did not significantly affect P. microspora growth. Leaf extracts of P. americana had the strongest inhibitory activity, followed by that of root and stem extracts. In this study, the ethanol extract from P. americana leaves had the greatest inhibitory effect on P. microspora, the causal agent of blueberry leaf spot, and thus, ethanol might be the best choice of solvents to extract bacteriostatic substances from P. americana. The study provides basic data for continued research and development of biopesticides.