The limiting of climatic factors and predicting of suitable habitat for citrus gummy bark disease occurrence using GIS

Gummy bark disease is a disorder of sweet orange on sour orange rootstock in Egypt. There is an importance for hot-growing temperatures to symptom development of citrus viroids. The geographical distribution of the gummy bark disease in some world countries depend on high temperatures for viroid-symptom expression. So, correlation between climatic factors and gummy bark disease through GIS is studied. We designed a satellite map for the gummy bark disease distribution all over the world using the previous registered results. Superimposed maps of BIOCLIM annual Min -temperature, Max-Temperature and the points distribution, indicated that gummy bark disease naturally occurs in the low temperature zones range from 8-18°C at winter and from 27-38°C at summer season where the altitude ranged from -351 to 1320 m. A novel method called maximum entropy distribution modeling was used for predicting potential suitable habitat for gummy bark disease in Egypt using occurrence records. The Maxent model's internal jackknife test of variable importance showed that altitude and mean temperature of driest quarter are the most important predictors of citrus gummy bark disease-habitat distribution. © 2012 Academic Journals Inc.