Application of GIS to Produce Lime Disease Spatial Distribution MapM. Damizadeh Agricultural and Natural Resources Research Center of Hormozgan Province P.O.Box 79159-1577, Bandar Abbas, Iran Tel. ++98-761-3333050 Fax: ++98-761-3332496 damizadeh@yahoo.com H. Hossaini pour Agricultural and Natural Resources Research Center of Hormozgan Province P.O.Box 79159-1577, Bandar Abbas, Iran Tel. ++98-761-3333050 Fax: ++98-761-3332496 Jalal Barkhordari Agricultural and Natural Resources Research Center of Hormozgan Province P.O.Box 79159-1577, Bandar Abbas, Iran Tel. ++98-761-3333050 Fax: ++98-761-3332496 Abstract GIS is an effective tool to monitor and control the various plant diseases. A number of papers discuss the applications of GIS in controlling, monitoring, and surveillance of infectious diseases. However, no research covers a wide number of contagious diseases with a common methodology with special treatment to a disease with respect to GIS application. The present paper attempts to analyze the distribution of Witch's broom disease of lime (WBDL) in the Minab County in the south of Islamic Republic of Iran with the application of GIS techniques. The main objective of the study is analyzing the spatial variation on the distribution of WBDL in Minab County with GIS operated cartographic databases. The results show the most of citrus gardens in the Minab County were infected and in the around of 50 percent of Minab villages, Witch's broom disease of lime can be seen. The results also show that the integration of GIS, GPS, and geostatistics provides a powerful tool for analysis plant disease. Introduction Vector-borne diseases have been the most important worldwide health problem for many years and still represent a constant and serious risk to a large part of the world. Witch's broom disease of lime (WBDL) is one of the most important plant diseases of today's Hormozgan province in the southern part of Islamic republic of Iran, so an understanding of spatial distribution of this disease is a fundamental component in the assessing citrus orchards risk for lime disease in much of this area. Recently, GIS and RS started to be used to evaluate and model the spatial distribution of plant disease or for relationships between environmental factors and the incidences of plant diseases. Such information when mapped together creates a powerful tool for monitoring and management of plant disease. GIS is particularly well suited for Epidemiologists in the study of associations between location, environment, and disease (Gesler, 1986). It has been used, for instance, in the plant disease epidemiology and management (Merritt R.Nelson,et al.,1999). Remotely sensed data also have been used in many vector disease studies (Beck et al., 1994; Ahearn et al., 1996). Remote sensing and GIS were used to identify villages at high risk for malaria transmission in the southern area of Chiapas, Mexico (Beck et al., 1994)., 1996). High-risk areas can be identified using GIS and remote sensing technologies that would otherwise be difficult to detect using traditional methods. Control and education programs can be directed toward these areas with more confidence and effectiveness. The present paper is part of a current research program on the witch's broom disease in Hormozgan province in the south of Islamic Republic of Iran. The project attempts to analyze the Disease pattern of witch's broom in the study area with the application of GIS techniques. Aim of Study The Objectives of the project are as follows:
The Study Area The study area is situated in Minab county in the Hormozgan province. It is located about 90km east of Bandar Abbas city, the capital of Hormozgan Province in the southern part of the Islamic Republic of Iran. The population of Minab County is 204588 that distributed in the 360 villages. Figure 1 shows the study area location.  Figure 1: The location of study area Disease Density Maps Plant disease monitoring and management practices can be improved using a geographic information system (GIS). GIS is a computer system capable of assembling, storing, manipulating, and displaying data referenced by geographic coordinates. New tools also, including global positioning systems (GPS) and geostatistics, are available to use in connection with GIS. GPS receivers determine location and are among the most important tools for spatially referencing agriculture data. WBDL lime disease density and its distribution in the study area were determined using these new tools. The data that used in this paper have been prepared from Jihad Agricultural Organization of Hormozgan province and it have been gathered from a research project that have been started in 2005 for monitoring of Witch's broom disease of lime (WBDL) in the Hormozgan Province. At the first, a database set up using Global Positioning System (GPS) and Geographical Information Systems (GIS). The data was collected using GPS and all trees infected by WBDL were referenced by GPS via field work. Lime disease cases were created and pointed with point symbol on the map. The geographic distribution of each case can be seen with point symbol on Density Map of WBDL in Minab County. The statistical maps displaying witch's broom disease density and its geographical distribution in the study areas were produced and displayed using ArcGIS 9.0 software and Geostatistics extension of this software.  Figure 2: Witch's broom disease of lime (WBDL) in the Minab County. Conclusions Figures 3 and 4 show disease density maps and spatial distribution map of WBDL in the Minab County in number and percent of infected trees formats. The results show the most of citrus gardens in the Minab County were infected and in the around of 50 percent of Minab villages, this disease can be seen. There are 3 areas that the disease is critical and the control programs must be focus on these particular areas. In the most of villages the number of infected trees is not more and it can be control using social programs or other methods that may be used to reduce the number of disease. This study can be used as a pilot project for presenting the distribution of WBDL density on the maps, producing control programs against lime disease, and examining environmental factors causing WBDL spatially. GIS offers powerful tools to present disease information to the level of individual occurrence. It can be used to display geographical distribution and pattern of disease, and its prevalence and incidence. Thematic maps can be generated to denote the intensity of disease or vector. GIS keeps track of the geographical locations of service providers, customers, resources, and health plans and programs. It permits dynamic link between databases and maps so that data updates are automatically reflected on the maps.  Figure 3: Spatial Distribution of WBDL in the Minab County. References
 Figure 4: Spatial Distribution of WBDL in the Minab County in percent of disease. |