Characterization and Pathogenicity of Botryosphaeriaceae Species Associated with Trunk Canker, Gummosis and Dieback of Almond Trees in Turkey

Abstract

Turkey is one of the leading almond countries in the world. Almond is a precious nut highly regarded in modern diets due to its bioactive compounds associated with health benefits and disease treatment. However, the yield of plant is affected by several factors, including pathogens. This study aimed to diagnose and identify biotic factors responsible for decline, dieback, and gummosis observed in almond trees in Yozgat province with a temperate climate. A thorough investigation was conducted in seven almond orchards and samples were collected from trees displaying aforementioned symptoms. The isolated species were cultured in PDA medium to identify the morphological and cultural characterization. The results obtained with cultural and morphological characteristics along with Phylogenetic analysis of ITS, β-tubulin, and EF-1α sequence data, confirmed the presence of Diplodia seriata, Lasiodiplodia theobromae, Neofusicoccum parvum, Botryosphaeria dothidea. Among these species, Botryosphaeria dothidea was first reported from almond trees in Turkey. Pathogenicity testing showed that although all species were virulent, L. theobromae and N. parvum isolates caused more gumming in the inoculation areas than D. seriata and B. dothidea isolates. These results confirmed that multiple species of Botryosphaeriaceae family are linked to branch decline and dieback on almond in Turkey, aligning with similar studies conducted on woody crops. Accurate diagnosis of fungal pathogens in almonds is vital for developing effective disease management strategies and may contribute to enhancing horticultural practices for the maintaince of urban almond stands.