Crop diseases and agricultural pests and pathogens are causing huge economic losses. The actual means for dealing with them involve the use of damaging chemical pesticides that harm the environment, threaten biodiversity, and undermine human health. This research was aimed at developing an environmentally friendly means to cope with emerging oomycete disease from tomato fields in the province of East-Azerbaijan. The oomycete disease causal agent was isolated and identified as Ovatisporangium sp. using a combination of morphological features and molecular methods. Six wood vinegars (pyroligneous acid) belonging to pine, pomegranate, pistachio, almond, walnut, and cypress were produced during this study and examined against Ovatisporangium sp. Their inhibition of volatile metabolites (VOCs) using different dilutions (1, 1/2, 1/4, 1/8, and 1/10) was assessed against the mycelial growth of Ovatisporangium sp. In vitro analysis demonstrated that pistachio, cypress, and almond dilution 1 (D 1) wood vinegar VOCs had the ability to stop the mycelial growth of Ovatisporangium sp. All other treatments including pine, walnut, and pomegranate with relevant dilutions significantly reduced the mycelial growth of Ovatisporangium sp. compared with the control (p ≤ 0.05). Wood vinegar is therefore a potent means to cope with pathogenic infections and allows plant protection against oomycete diseases.