Phoma Leaf Spot Disease of Tinospora Cordifolia and its Effect on Secondary Metabolite Production

Tinospora cordifolia is one of the important medicinal climbers growing extensively in Bhadra Wildlife Sanctuary, Karnataka, India. The plant foliages were found infected with Phoma putaminum in different parts of the sanctuary. A three‐year (August 2006–July 2009) study of the disease due to the pathogen indicated that the disease incidence (DI) ranged from 0 to 100% (maximum in Kakanahasudi), while disease severity (DS) ranged from 1.60 to 45.00% (maximum in Madhuguni). The environmental parameters like rainfall and relative humidity (RH) correlated significantly with DI and DS, while temperature correlated negatively. The regression analysis indicated that DI and DS were affected due to increase in RH and decrease in temperature and rainfall. The spatial heterogeneity of the foliar disease determined by the binary form of modified Taylor's power law indicated that the disease incidence showed the regular pattern of dispersion (P < 0.001) in seven forest regions and heterogenous pattern (P < 0.001) in one forest region. The result also indicated that the alkaloid content decreased drastically following infection with P. putaminum, while phenol, flavonoid and steroid contents increased with increase in the severity of infection.