Abstract
Neoscytalidium dimidiatum (Penz.) Crous & Slippers has been causing significant damage to apricot trees in Turkey in recent years. This disease can lead to various problems in apricot trees, including dieback, the formation of cankers, necrosis in vascular tissues, gumming, and ultimately the death of the host. This study was conducted in 2021–2022 in the region with the highest apricot production in the world, Malatya, Türkiye. This research aims to develop a control strategy against N. dimidiatum, which poses a destructive threat to apricot trees. In the study, the effectiveness of 10 chemical and 2 biological fungicides was tested in vitro and under field conditions to manage N. dimidiatum. While the effectiveness of chemical fungicides was assessed both in vitro and under field conditions, the effectiveness of biological fungicides was tested only under field conditions. Given the absence of a study conducted under field conditions for the controlling of N. dimidiatum, this aspect of the research is groundbreaking. In vitro experiments were performed in three replicates for each of the chemical fungicides. In the conducted in vitro experiments, most of the tested chemical fungicides, except for metalaxyl-m + acibenzolar-s-methyl (10.46%), effectively inhibited the mycelial growth of N. dimidiatum. In terms of inhibiting the mycelial growth of N. dimidiatum, the most effective fungicides were ranked as follows: tebuconazole (100%), cyprodinil + fludioxonil (99.43%), azoxystrobin + difenoconazole (99.40%), and floupyram + tebuconazole (99.26%). Chemical fungicides that exhibited high efficacy under in vitro conditions also proved to be effective in field trials. Among these fungicides, azoxystrobin + difenoconazole, floupyram + tebuconazole, and tebuconazole were identified as the most effective fungicides both before and after artificial inoculation. Cyprodinil + fludioxonil showed high efficacy when applied before inoculation but was not effective when applied after inoculation. In contrast to the chemical fungicides, the commercial Bacillus subtilis and Trichoderma harzianum Rifai KRL-AG2, which were exclusively examined in field studies, did not display significant effectiveness against N. dimidiatum.