In vitro Evaluation of Some Biological Agents in Controlling Neoscytalidium dimidiatum, the Causal Agent of Apple Wilt and Stem Blackening

Abstract

Al-Karaawi, K.Z.K. 2026. In vitro Evaluation of Some Biological Agents in Controlling Neoscytalidium dimidiatum, the Causal Agent of Apple Wilt and Stem Blackening. Arab Journal of Plant Protection, 44(3):390-395. https://doi.org/10.22268/AJPP-001411 This study aimed to isolate and diagnose the fungal pathogen causing apple wilt and stem blackening disease. The results obtained identified the pathogenic fungus Neoscytalidium dimidiatum, with a similarity of 99% with the previously diagnosed Chinese isolate, as the causal agent of apple and stem blackening disease, and for its ability to produce several enzymes that permit the fungus to attack its host, including pectinase, protease, and amylase. Results obtained also showed that the antagonistic ability of Bacillus subtillis bacteria, at a concentration of 22.8×108 CFU/mlreached 100% inhibition. İn addition, the fungus Trichoderma harzanium gave a high antagonistic activity against the pathogenic fungal isolate on PDA medium, reached 98.61% inhibition, seven days after treatment. Keywords: Apple, wilt, B. subtillis, N. dimidiatum, T. Harzianum.