First report of stemphyllium leaf blight diseases on shallots in West Sumatra, Indonesia

Abstract

Stemphyllium leaf blight (SLB) is one of the diseases that cause losses in shallots. This study aims to detect the presence of SLB disease and determine the percentage of disease incidence and severity in West Sumatra. The study used survey methods, sample collection, and disease measurement in three shallot production centers in West Sumatra districts, namely Solok, Agam, and Tanah Datar. The damage caused by this disease is determined by measuring the percentage of disease incidence and severity. Infected plants were isolated to identify the cause of the diseases. The survey results have found symptoms of SLB which has never been reported before. Symptoms on the leaves are small round spots that coalesce to form a blight which then develops into a brown lesion and turns black in the center of the lesion due to sporulation over time. The disease incidence was 12.15%, and the severity was 5.97%. Based on morphological identification, microscopy, and pathogenicity tests, it was found that the cause of this disease was Stemphyllium sp. It is the first Stemphyllium sp. report on shallots in West Sumatra.