Diseases

Helminthosporium Leaf Blight of Maize

Zea mays L. subsp. mays (Maize Group)

A group of maize diseases caused by pathogens Cochliobolus heterostrophus (southern corn leaf blight) and Setosphaeria turcica (northern corn leaf blight), affecting leaves and generative organs.

In the reference 244 varieties crop Maize, where this is mentioned in the description.

Southern corn leaf blight, caused by Bipolaris maydis, is subdivided into races O, T, and C. Race T possesses high virulence to hybrids with Texas male-sterile (T) cytoplasm by producing a host-specific toxin. Symptoms manifest as spindle-shaped lesions with a dark center and velvety mold on the ears, leading to kernel rot.

Northern corn leaf blight, caused by the pathogen Exserohilum turcicum, is characterized by the appearance of large brown lesions measuring up to 10–25 cm in length with a reddish-brown border. Under high humidity, the lesions are covered with the olive-colored sporulation of the pathogen.

Breeding for resistance relies on the use of specific genes, such as HM, responsible for the response to toxins, and the rhm1 gene associated with resistance to southern corn leaf blight. In most cases, varietal resistance is considered a quantitative trait inherited through additive and dominant gene effects, controlled at the level of QTL loci.

General information about the subject — on the page Helminthosporiosis.

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Zea mays L. subsp. mays (Maize Group) · Maize

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