Physiological Studies of Myrothecium Roridum: An Inciting Agent of Myrothecium Leaf Blight in Cotton

Abstract

Background: Cotton is one of the most important cash crops in India. It is also called as “White gold” because of its agricultural as well as industrial importance. Myrothecium leaf blight is an emerging disease in cotton which is growing consistently throughout the country and has been reported to cause significant losses in major cotton growing tracts of odisha. Considering the importance of the disease, the present investigation has been taken up to study the physiology of the fungus. Methods: An experiment was conducted in-vitro during 2016-18 to investigate the effect of temperature and pH on the growth of M. roridum. Seven different nutrient media viz. Potato Dextrose Agar (PDA) medium, Potato Sucrose Agar (PSA) medium, Host Leaf Extract Agar (HEA) medium, Potato Carrot Agar (PCA) medium, Czapek’sdox Agar (ZA) medium, Richard’s Agar (RA) medium and Oat meal agar medium (OMA) were tested under in-vitro conditions to ascertain a suitable medium for the growth of M. roridum. Result: The investigation in laboratory conditions has revealed that out of seven nutrient media tested, maximum radial growth was recorded in Potato Sucrose Agar (PSA) with an average radial growth of diameter 76.06 mm and the least growth was recorded on Richard’s Agar with a diameter of 23.66 mm. The growth of the fungus was observed to be maximum at a temperature of 28oC with a diameter of 61.09 mm and the minimum average growth of 17.36 mm was recorded at 36oC. Studies on pH revealed that that the fungus grows well in neutral and slight alkaline medium (6.5 - 8.0).