Regional Monitoring of the Dynamic of Wheat Leaf Rust (Puccinia triticina Eriks) in Southwest of Iran, Khuzestan Province

In this study, the first symptom appearance of wheat leaf rust disease was monitored in Khuzestan Province every ten days from early December 2014, for three years. Also, the climate changes and their influence on the development of the disease were studied. During 2014-2015, the first symptoms, with the severity of 5 MS (Moderately Susceptible), appeared in the south and west parts in early and mid-March, respectively. In northern areas, the symptoms appeared with 10 MS severity in early May. In 2015-2016, the first symptoms appeared with the severity of 5 MS in February in the southern areas. In the west, symptoms appeared and reached 20 S (susceptible) on March 10. In the north, the disease started in late February with the severity of 10 MS and developed to 30 S. In 2016-2017, the first symptoms appeared around the Karun River with the severity of 5 MS on March 10 and eventually reached 10 MS in late March. In the western areas, the disease started in early March with the severity of 5 MS and then stopped. Symptoms appeared one week later in the north, with the severity of 5 MS, and reached 15 MS until the end of March. Based on the previous studies, the first symptoms of wheat leaf rust usually start from the west. However, now, the regional pattern of the symptom has changed dramatically, and it appears in the south near Karun River and the Sugar Cane Crop Industry. This might be due to implementation of preventive measures and dryness of a big part of Hoveyzeh Marshland.