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United States Department of Agriculture

Agricultural Research Service


item Irey, Michael
item Gottwald, Timothy
item Graham, Jim
item Carlton, G.
item Riley, Tim

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 9/30/2005
Publication Date: 11/7/2005
Citation: Irey, M.S., Gottwald, T.R., Graham, J., Carlton, G., Riley, T. 2005. Post-hurricane analysis of citrus canker spread and progress towards the development of a predictive model for future weather related spread. Proceedings of the International Citrus Canker and Huanglongbing Workshop, Orlando, FL, Nov. 2005. C5, p15.

Interpretive Summary:

Technical Abstract: Citrus canker, caused by Xanthomonas axonopodis pv. citri (Xac), has been introduced into the state of Florida multiple times since the early 1900’s. With each discovery, an eradication program has been put into place to eliminate the disease. The most recent program began in 1996 and is still in progress. The current citrus canker eradication program (CCEP) is a joint project operated by the Florida Department of Agriculture and Consumer Services (FDACS) and the Animal and Plant Health Inspection Service of the United States Department of Agriculture (USDA-APHIS). FDACS is responsible for the survey and eradication of Xac in the commercial industry and USDA-APHIS has largely been responsible for residential and commercial grove sentinel surveys. As Xac infections are found by either survey agency, the location (latitude and longitude) of all finds are recorded and entered into a spatial database. During 2004, the state of Florida was directly affected by four hurricanes that carved different paths across the state and directly impacted commercial citrus and various residential communities with pre-existing Xac infections. In the 12 months following the 2004 hurricanes, the monthly frequency of detection of citrus canker has increased up to 4-fold, presumably as a result of wind-blown rain associated with the hurricanes. Analysis of the spatial distribution of post-hurricane Xac finds in conjunction with weather data collected during the storm events has lead to the development of model that accounts for a significant portion of the post-hurricane Xac spread. The model incorporates wind speed, wind direction, and precipitation over time to calculate wind/rain vectors (Figure 1) that predict the direction of weather-related disease spread (Figure 2). Due to the paucity of weather recording stations within the commercial citrus industry, the use of interpolated weather data derived from mesoscale weather models is being investigated as a source of environmental data to seed the spread model. Work is also underway to refine the model to predict distance of spread as well the direction of spread. Once fully validated, the model will be turned over to the CCEP and used with real-time weather data to predict Xac spread events in order to maximize the resources allocated to the eradication program.

Last Modified: 10/17/2017
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