author(s)
Dr. Meena Kumari, Dr. SC Verma and Dr. NK Bharat

abstract
The present investigations were conducted during 2014 and 2015 to study the effect of elevated CO₂ and temperature on diseases viz. Phytopthora blight and Cercospora leaf spot infestation and severity on bell pepper (Capsicum annuum L.), respectively. The experiment was carried out under four conditions, i.e. three Open Top Chambers, (T₁: OTC with elevated CO₂ 550±10 ppm; T₂: OTC with elevated temperature 1^â—¦C and elevated CO₂ 550±10 ppm; T₃: OTC with ambient temperature and CO₂ (reference) and T₄: natural air and temperature). The present study reveal that the maximum Phytophthora blight incidence was under elevated CO₂ and temperature (22.71%) which differed statistically with elevated CO₂ (16.29%), ambient CO₂ and temperature (11.09%) and natural condition (9.24%). California Wonder recorded significantly higher Phytophthora blight incidence (17.81%) as compared to Solan Bharpur (11.87%). Amongst all treatments, higher Cercospora leaf spot severity was under elevated CO₂ and temperature (7%) which was statistically at par with elevated CO₂ (5.82%) and differed statistically from ambient CO₂ and temperature (5.22%) and natural condition (3.86%). Cercospora leaf spot severity was significantly higher (6.11%) in California Wonder as compared to Solan Bharpur (4.84%). Both elevated temperature and CO₂ had significant effects on diseases infestation and severity of Phytopthora blight and Cercospora leaf spot, respectively. The crop productivity of bell pepper was affected due to the increase incidence and severity of diseases under changing climatic conditions, i.e. elevated CO₂ and temperature.