Leaf spot caused by Alternaria crassa on Datura stramonium in Turkey

Abstract

In August 2021, jimson weed (Datura stramonium) plants growing as weeds in potato fields in Bolu province, Turkey, exhibited leaf spots with dark concentric rings. Sunken and lens-shaped lesions with a light center were also frequently observed on petioles, branches, and stems. Based on morphological characteristics and phylogenetic analysis of the transcription elongation factor 1-α, RNA polymerase second largest subunit, and glyceraldehyde-3- phosphate dehydrogenase loci, the causal agent was identified as Alternaria crassa. The pathogen was successfully re-isolated from inoculated jimson weed plants in the pathogenicity assay, proving Koch’s postulates. Alternaria crassa caused necrotic lesions on potato plants, similar to those of early blight, confirming them as an alternative host of the pathogen. This is apparently the first report of leaf spot caused by A. crassa on jimson weed in Turkey.