The fungus infects the lower stem of the plant near the surface of the soil. The disease was first reported on tomato, but also occurs on hundreds of other economically important crops including pepper, bean, cantaloupe, carrot, potato, sweetpotato, watermelon, cotton, peanut, tobacco, and soybean. Southern corn leaf blight (SCLB) is a fungal disease caused by Cochliobolus heterostrophus, often found in the literature under various names … Scientific Name. A purplish to brown border may appear around the lesions, depending on the genetic background of the plant. Southern corn leaf blight lesion symptoms range from minute specks to spots of 1/2 inch wide and 1-1/2 inches long. Southern corn leaf blight, caused by Race T of the fungus Bipolaris (Helminthosporium) maydis, forced US crop breeders to consider the detrimental effects of planting only one genotype of a crop.If the specific genotype used isn’t resistant to a particular invader, then the whole crop could be lost if the pathogen establishes itself in the environment. The first symptom is the wilting of the the plant. At the collar region of the stem you may notice a brown blighted section. Xylella fastidiosa is an aerobic, Gram-negative bacterium of the monotypic genus Xylella.It is a plant pathogen, and is transmitted exclusively by xylem fluid feeding sap insects. Under the right conditions, conidia (asexual spores) are released from wounds of a diseased corn plant and dispersed to surrounding plants through splashing rain or wind. The southern corn (Zea mays L.) leaf blight (SCLB) epidemic of 1970–1971 was one of the most costly disease outbreaks to affect North American agriculture, destroying 15% of the crop at a cost of US$1.0 billion (≥$6.0 billion by 2015 standards. It is caused by the soil borne fungus Sclerotium rolfsii. Southern blight is not common on wheat and small grains, but it does occur on cool season turf species such as bentgrass, fescue, perennial ryegrass, bluegrass, and broad leaf turf species such as Dichondra spp. Southern leaf blight, southern corn leaf blight, southern leaf spot, maydis leaf blight. The disease attacks a wide range of vegetable crops and ornamental plants at or below the soil line. They are oblong, parallel-sided, and tan to grayish in color. Southern blight is caused by a soil-borne fungus called Athelia rolfsii, which is nearly impossible to eradicate even though it exists in relatively low levels. There are different races. when conditions are warm (above 24ºC / 75ºF) and moisture is abundant. Southern blight, southern wilt, southern stem rot and southern root rot all refer to the same disease. Southern corn leaf blight is caused by the fungus Bipolaris maydis, which primarily follows an asexual disease cycle. Cochliobolus heterostrophus; this is the name for the sexual stage; the asexual stage is known as Bipolaris maydis (previously it was Drechslera maydis and before that Helminthosporium maydis). In 1970 the losses to corn leaf blight approaches 710 million bushels. Southern corn leaf blight incited by Helminthosporium maydis Nisikado & Miyake evolved from a minor disease that causes an average annual loss of less than 1 percent, to one that caused more than the 12 percent average expected from all diseases of corn in the United States. Southern blight, also known as southern wilt and southern stem rot, is a serious and frequent disease of vegetable crops in North Carolina. Southern blight symptoms are typically seen in warm, humid conditions.