Epidemiological Relations to Phytophthora Spp. Causing Citrus Root Rot in Nagpur Mandarin

Epidemics caused by Phytophthora spp. were monitored in four commercial citrus orchards to plot correlation between environmental and soil factors with root rot disease caused by Phytophthora spp. in citrus. Agro - meteorological d ata was recorded by using wireless sensors (for air temperature 107 Temperature probe, for relative humidity HC2S3 with 30 minutes time interval for both the sensors and for rainfall measurement Texas Electronic rain gauge) in selected plots. The soil mois ture, soil pH and soil EC was recorded at fortnightly interval. The observations recorded in order to characterise the progression of the symptoms expression over the time and to provide evidence for the possible correlation of inoculum dynamics with root rot and environmental factors. The relationship of rainfall, temperature, relative humidity, soil moisture, soil pH and soil EC on disease development was investigated. Sensor based data was recorded for rainfall, temperature, relative humidity and convert ed to forth nightly interval. The disease progress and inoculum potential recorded at forth nightly interval from June 2016 to May 2017. There was significant progression in the disease development with the increase in the rainfall and soil moisture. There was significant increase in the disease at second fort night of August (38.53%) and progression continued up to October (87.58%). Progress in disease was attributed to increase in soil moisture, relative humidity and decrease in the air temperature. A ten dency of spreading the disease at adjoining trees was observed. Drainage of water, possibly containing propagules of the pathogen may have been responsible for disease progression. The disease initially low but gradually increases with time. There was posi tive correlation between rainfalls, soil moisture, relative humidity, soil EC with disease progression and inverse correlation with air temperatur