For the disk diffusion test, a small plate (6 cm diameter) containing 10 mL PDA or cV8 was used for the disk diffusion test. cV8 plates were used for P. infestans and P. sojae instead of PDA plates owing to slow growth in the PDA plate. Two layers of sterile filter paper discs (0.6 cm diameter) that contained EtOAc extracts [100 μg/10 μL of water (1:9, v/v)] as treatment and acetone–water (1:9, v/v) as a control were placed on the surface of PDA or cV8 plates at 3 cm from a Phytophthora plug (0.6 cm diameter) that had been cut from the actively growing edge of and placed on the plate mycelial side down. The plate was then incubated for 5–13 days at 18–30 °C until Phytophthora growth in the control reached the edge of the plate. The colony diameters of each Phytophthora were measured daily, after which the growth inhibition (%) in response to the EtOAc extract relative to the control was calculated using the formula provided above ( Satish et al., 2007). Each experiment was repeated twice, with three biological replications per experiment.