Epidemiological relations to population dynamics of Phytophthora spp. in Mandarin

Fixed plot survey was undertaken to plot correlation between environmental factors with population of Phytophthora spp. in soil and the disease intensity during June 2015 to May 2016. Agro-meteorological data was recorded by using wireless sensors (for air temperature 107 Temperature probe, for relative humidity HC2S3 and for rainfall measurement Texas Electronic rain gauge) in selected plots. All four orchards were found infected with Phytophthora in the range of 3.2–43.6 cfu/g of soil. There was consistent increase in pathogen population in all plots with increase in rainfall, relative humidity with decrease in temperature and vice versa. At high rainfall condition intensity of root rot was increased to 35.81 per cent in the month of August and gummosis (41.01%) was also increased in the month of October with average propagules of 25.84 cfu/g of soil. Increase in temperature decreased intensity of gummosis (26.29%) and root rot (20.09%) in the month of May, with the average propagules, i.e., 4.56 cfu/g of soil. Present findings suggest that, humidity and rainfall were significantly correlates with population dynamics of Phytophthora spp. and disease intensity, while temperature was found inversely proportional.