Assessment of Pathogenicity in Helminthosporium maydis causing Southern Corn Leaf Blight Disease in the Region of Karnataka

Maize (Zea mays L) is the one of the most beneficial crops, adapted to various ecological and climatic states, it grades third after wheat and rice. Based on the research determinations for the last few years under the leadership of All India Coordinated Maize Improvement Project, 16 out of 61 diseases harmfully affecting this crop. One of the major diseases is Southern corn leaf blight (SCLB). The causative agent of the prevalent was recognized as the fungus Helminthosporium maydis. Research was carried out for pathogenicity assay. Pathogenicity assay was conducted with two methods, by collecting spores (2X105/ml), spraying on one month old maize plant. After 24 – 48 hours, it was found that spores collected from Davanagere (HMS3) and Kodagu (HMS5) region shows more yellow to brown lesion compare to all other regions. Second by extraction of toxin by methanol – chloroform method, purification by adsorption on charcoal and separated by using column chromatography and by thin layer chromatography. The Rf values, FTIR and UV absorption spectrum of purified toxin reveals the production of host specific toxin by H.maydis. Determination minimum toxic concentration required to satisfy the conditions as a host specific toxin. Keywords: Survey, Pathogenicity, Extraction, Host specific Toxin, Southern Corn Leaf Blight