Distribution Pattern of Southern Corn Leaf Blight in Khyber Pakhtunkhwa-Pakistan and Its PCR Based Detection in Asymptomatic Leaves and Plant Debris

Southern corn leaf blight, caused by Bipolaris maydis, is an important disease of maize in Khyber Pakhtunkhwa (KP) province, Pakistan. Extensive surveys were carried out during kharif 2015 to assess the distribution pattern of the disease in various districts of KP. The disease was prevalent in all surveyed areas with varying degree of severity. Plains of KP were more prone to the disease due to favorable environmental conditions than highlands. A direct PCR protocol for detection of the pathogen in asymptomatic leaves was developed using species specific primers JB588/JB591, JB587/JB596 and JB588/JB598. Primer pairs JB588/JB591 and JB587/JB596 were equally effective in detecting the pathogen as compared to the primer pair JB588/JB598. Nested PCR was however required to detect the pathogen in plant debris. Primer pair JB587/JB596 proved reliable in detecting the pathogen in plant debris through nested PCR.