First report of Rhizoctonia solani Kühn ag 4 causing root and basal rot of sweet basil (Ocimum basilicum L.) in Bulgaria

Ivo Yanashkov, Tzennko Vatchev

Abstract: Symptoms of root and basal stem rot were observed on individual basil (Ocimum basilicum L.) plants in July and August 2018 and 2019 in household kitchen gardens in the Bulgaria. All symptomatic plants irreversibly wilted, withered and eventually died. Eight fungal isolates obtained from symptomatic basil plants were identified as Rhizoctonia solani Kühn on the basis of colony morphology and microscopic observation of their morphological characteristics. The isolates were assigned to anastomosis group 4 (AG 4) of R. solani according to hyphal anastomosis reactions with tester isolates. Pathogenicity of each individual isolate was confirmed in pot experiments with artificially inoculated basil plants, c. Genovese. To the best of our knowledge, this is the first report of root and basal rot disease caused by R. solani AG 4 on basil (O. basilicum) in Bulgaria and elsewhere.

Keywords: anastomosis group 4 (AG 4); basil; pathogen; Rhizoctonia solani; root and basal stem rot

Date published: 2021-11-10