Weather Parameters Influencing the Incidence of Citrus Canker Caused by AW Strain in the Rio Grande Valley

Citrus canker caused by bacterium Xanthomonas citri subsp. citri (Xcc) seriously affects the citrus industry by making the fruit unmarketable due to unsightly lesions on the fruit. Canker caused by Aw strain of Xcc was reported in the citrus trees located in the residential areas of the Rio Grande Valley (RGV). Canker severity differs amongst cultivars/varieties, and it is influenced by prevailing environmental conditions. Multiple regression modeling of the disease incidence with the environmental variables such as temperature, humidity, windspeed, wind gust, and rainfall was performed to understand the environmental conditions that are favorable for spread of citrus canker caused by Aw strain in the RGV. Our results reveal two statistically sound models that are fit to the data. Model 1 predicts the significant effect of temperature, humidity, wind gust, and wind speed while Model 2 predicts the significant effect of temperature, humidity, wind gust, wind speed, and rainfall on citrus canker spread. However, Model 1 is preferred over Model 2 as Model 1 shows better model diagnostics than Model 2. Additionally, precipitation cannot affect the citrus canker negatively as in case of Model 2. Knowing the environmental conditions in the RGV that favors the spread of canker caused by Aw strain, one can design better management practices before disease becomes an epidemic