Koc, I2025-10-152025-10-1520251589-16231785-0037https://doi.org/10.15666/aeer/2305_88818894https://hdl.handle.net/20.500.12514/9815Pathogenic fungi damage ornamental plant production in both quality and quantity. Organic fungicides are significantly needed for the control of these pathogens. This study was carried out to analyze the content of pyrolysis liquid (PL) obtained from green walnut shells (Juglans regia L.) and to evaluate its antifungal activity against Fusarium oxysporum and Verticillium dahliae. This research was carried out under in vitro conditions with 5%, 10%, 15%, 20% and 25% (v/v) PL solution applications in a Randomized Plot Design with four replications. The Poisoned Food Method was used to determine the antifungal activity of PL. As a result of chemical content analysis of PL, 53 components were detected by GC-MC, and the major components were propanoic acid, 2-hydroxy-(CAS) (21.69%), e-2-undecenal (7.11%), and nonanal (5.76%). Twelve components were detected by LC-MS/MS, with vanillic acid (393.28 mu g/L), vanillin (334.34 mu g/L), and syringic acid (222.80 mu g/L) identified as the major components. Total phenolic content (201.76 +/- 12.50 mg GAE/mL) and total flavonoid content (114.74 +/- 4.50 mg QE/mL) were determined. Therefore, the effect of concentration on colony size varied depending on the species. It was determined that PL showed stronger antifungal activity at higher concentrations, with the highest activity observed at the 25% (v/v) solution.en10.15666/aeer/2305_88818894info:eu-repo/semantics/closedAccessBiomassGC-MCLC-MS/MSTotal PhenolicTotal FlavonoidArticle