Garlic yellowing disease in Zanjan Province

Garlic is an herbaceous plant from the Alliaceae, which ranks second among Allium species after onions in terms of global production. Garlic is one of the most widely grown crops in Tarom County, Zanjan Province, Iran. Recently, a new disease with symptoms of severe yellowing and terminal drying of the leaves, known as garlic yellowing disease, was observed in many fields of Tarom County of Zanjan province. To identify the causal agent and assess the prevalence of garlic yellowing disease in Tarom, symptomatic leaves were collected from fields for three years. After isolation, the cause of garlic yellowing disease was identified as Stemphylium vesicarium, based on both morphological characteristics and sequencing of the rDNA-ITS, glyceraldehyde-3-phosphate dehydrogenase (gapdh) and calmodulin (cmdA) genomic regions. A severe epidemic of yellowing disease on garlic caused by S. vesicarium was found in all garlic fields in Tarom.