Analysis of factors and establishment of primary prediction model for citrus canker disease occurrence in‘Bingtang'sweet orange

【Objective】In order to explore the epidemiological regulation of canker disease of‘Bingtang'sweet orange based on the phenology of the host and the meteorology in the orchard,an estimation equation for prediction of the disease appearance was established to guide the effective control of the disease.【Methods】A Vantage Pro2 automatic meteorological recorder was installed in the orchard for regular recording meteorological data. The phenology and the disease occurrence on young shoots and young fruits of‘Bingtang'sweet orange were continuously recorded,and then an estimation equation was built up.【Results】The disease occurrence was closely related to the phenology o‘fBingtang'sweet orange and meteorological factors in the orchard. The first canker disease spot did not appear until the young leaf reachedthe full size and the young fruit after the first physiological fruit drop. High temperature,windy andrainy weather were necessary for the disease development. The disease occurrence on fruit was closely related to rainfall,air temperature,average wind speed,relative humidity and other meteorological factors. Among young shoots,the disease index was the highest on the spring flush,followed by the summer and fall shoots.【Conclusion】The bi-variable correlation analysis was conducted between the average temperature of every five consecutive days and the days of the 1st disease symptom occurred onspring and summer leaves in 2011 and 2012,which showed significant negative relationship betweenthem. And then a prediction equation was established to provide the basis for guiding the disease prevention and control.