Effect of Temperature, pH and Relative Humidity on Growth of Root Rot Disease of Soybean

Abstract

Root rot of soybean constitutes a widespread and serious disease constraint in Maharashtra and several other soybean-growing regions of India, leading to substantial yield reductions. The incidence and severity of the disease are often exacerbated under conditions of high temperature and low soil moisture, as well as other unfavourable environmental stresses. Under such conditions, plants become physiologically weakened, thereby increasing their susceptibility to pathogen infection and disease development. Rhizoctonia bataticola causal agent of root rot and charcoal rot in various pulse crops. Due to fluctuation of temperature and climatic disturbance in the arid region is quite difficult to manage the root rot. Due to favourable weather circumstances, the disease spread widely across the state and resulting in significant yield losses. To reduce the number of sclerotia in soil or to minimise the contact of the inoculum and the host, six different temperatures and four pH levels were tested for their suitability on mycelial growth and sclerotial formation of the Rhizoctonia bataticola in vitro conditions. Maximum mycelial growth (88.33 mm) was observed at 30 oC temperature followed by 25ºC (66.33 mm), 35ºC (64.00 mm), 20 ºC (54.33) and 40ºC (27.00 mm) and maximum dry mycelial diameter (86.25 mm) was observed at 6.5 pH followed by pH level 5.5, 7.5, and 8.5 with colony diameter 71.33, 55.58, mm and 47.00 mm of the R. bataticola respectively. Root rot of soybean constitutes a widespread and serious disease constraint in Maharashtra and several other soybean-growing regions of India, leading to substantial yield reductions. The incidence and severity of the disease are often exacerbated under conditions of high temperature and low soil moisture, as well as other unfavourable environmental stresses. Under such conditions, plants become physiologically weakened, thereby increasing their susceptibility to pathogen infection and disease development.