Weather Conditions Associated with Citrus Canker Incidence Caused by AW Strain in the Lower Rio Grande Valley of South Texas

Citrus canker, caused by bacterium Xanthomonas citri subsp. citri (Xcc), affects the citrus industry by making the fruit unmarketable due to unsightly lesions on the fruit. Citrus canker caused by a relatively new AWstrain of Xcc was reported on the citrus trees in the residential areas of the Lower Rio Grande Valley (LRGV) of South Texas. Xcc AW has a limited host range, predominantly affecting limes and a few other citrus species. Previous work has reported prevailing environmental conditions that influence the incidence and spread of the citrus canker caused by the Asiatic A strain. However, no information is available on the environmental factors impacting the incidence of canker caused by AW strain. In this study, monthly data on temperature, humidity, rainfall, and wind speed were grouped into biologically meaningful categories, and corresponding disease incidence was examined descriptively. Disease incidence was highest under high temperatures, humid conditions, and particularly during periods of rainfall and high wind speeds, which likely facilitated bacterial dispersal. These observed patterns indicate that warm, humid, rainy conditions, and stronger winds are associated with increased citrus canker incidence in the LRGV. This study provides insights into environmental conditions conducive to disease incidence and may serve as a foundation for developing explanatory and predictive models leading to management strategies for protecting citrus production in South Texas.