Cultural characterization of Exserohilum turcicum causing turcicum leaf blight of maize in Manipur

Maize (Zea mays L.), known as the "queen of cereals, "is cultivated worldwide for its versatility, with every plant part having economic value. Turcicum Leaf Blight (TLB), caused by Exserohilum turcicum, is a major foliar disease limiting maize productivity. This study examined seven E. turcicum isolates (ET1-ET7) for their cultural and morphological variability. Colony color ranged from greyish-black to black and light greyish, though all isolates showed black pigmentation. Sporulation varied, with ET4 and ET6 being highly sporulative, while ET2 and ET5 were poor. Surface textures were rough or fluffy, and colony margins showed varying degrees of branching. Radial growth was tested on seven media, with Oatmeal Agar supporting the highest growth (7.50 cm) and Rose Bengal the least (4.18 cm). ET6 showed maximum average growth (6.57 cm), while ET2 had the lowest (3.42 cm). Growth was optimal at pH 6 and declined significantly at extreme pH levels. In liquid media, Oatmeal broth produced the highest biomass, with ET6 again being the most productive. ET2 consistently showed minimal growth and biomass.The results highlight significant variation among isolates, emphasizing the need for screening diverse maize genotypes for resistance. These findings aid in developing effective breeding strategies against TLB.