Bipolaris maydis is a fungal pathogen of hybrid corn, teosinte, and sorghum and causes Southern Corn Leaf Blight (SLB) in susceptible corn varieties [1]. ย
B. maydis has three races of note: race C, race O, and race T. ย Race C is limited to China, while races O and T are found throughout the temperate and subtropical corn growing areas of the world [1]. ย
Race O affects normal hybrid corn and produces tan lesions along leaf veins. ย This race is limited to these lesions and does not cause significant damage to the plant or yields [1]. ย
Race T affects Texas sterile hybrid corn, also known as T cytoplasm corn. ย This particular variety of hybrid corn was developed to eliminate the need for manual detasseling of the female parent in commercial corn crops [2]. ย T cytoplasm corn produced sterile females and contained a restoration gene to restore fertility to the male line. ย Unfortunately, T cytoplasm corn also contained a specific site on cell mitochondria for the race T toxin to bind to [2]. ย Race T is the most virulent race of the three B. maydis races, capable of devastating crops with its quick lifecycle and host/toxin specificity [2]. ย
A field showing the difference between corn plants infected with Race O vs Race T. ย Race T plants are visibly chlorotic, stunted, and overall unhealthy.ย