Change Analysis On Suitable Distribution Areas Of Two Citrus Fruit Flies In China And Establishment And Application Of Warning System

Citrus is one of the most important economic crops in southern China. There are a wide variety of citrus pests in China, in which the citrus fruit flies are the destructive pests for citrus, mainly including Bactrocera dorsalis (Oriental fruit fly) and Bactrocera minax (Chinese fruit fly). In recent years, the damaging ranges of citrus fruit flies further extend to be worse and more serious in some regions. The risk of the citrus fruit flies have received considerable attention due to that the citrus in Guangyuan, Sichuan Province was infected by Bactrocera minax in2008. With the deteriorating of the global warming, it may affect the suitable distribution of the citrus fruit flies. At present, there is a wide range of monitoring for the citrus fruit flies in China. Since citrus fruit flies have occurred in certain regions, it is difficult to monitor and control the citrus fruit flies. Therefore, Computer technology, Database and Spatial Information were used to establish the monitoring and warning system for citrus fruit flies. Besides, it can accelerate information transmission and improve monitoring effciency; and it is of important significance for the prevention and controlling of citrus fruit flies.In this paper, DYMEX and ArcGIS were used to study the change trend of suitable distribution of the citrus fruit flies in China, and ASP.NET, Silverlight, ArcGIS Server, SQL Server were used to establish the monitoring and warning system for the citrus fruit flies based on WebGIS. This system established was successfully integrated into the results of DYMEX. This paper aims to meet the demands of monitoring for the plant protection, such as reporting, querying and analyzing monitoring data, browsing the monitoring space information, and releasing the warning information of citrus fruit flies and so on. It can assist the plant protection to trace the dynamics of citrus fruit flies in monitoring regions, and develop appropriate strategies to manage the risk posed by the pests. The main contents and results are as follows:1. The critical factor and the change trend of suitable distribution of citrus fruit flies under climate changeDYMEX and ArcGIS were used to analyze on the change trend of suitable distrubiton of citrus fruit flies under climate change in China, respectively. The change trend of suitable distributions for Bactrocera dorsalis and Bactrocera minax during1961-1990, and1981-2010period were investigated; their suitable distributions in China in2020were predicted. In addition, the critical factors that influence suitable distribution were analyzed. The results are as follows: (1) Change trend of suitable distribution for Bactrocera minax. The range for suitable distribution of B.minax was limited to97.69～122.25°E,22.44～34.30°N in China, including Guizhou, Hunan,Yunnan, Sichuan, Chongqing, Hubei,J iangxi, Zhejiang, Fujian, Guangxi,Guangzhou, Gansu, Anhui during1961-1990. The range for the suitable distribution of B. minax has little changed during1981-2010, but the northern boundary for B.minax extend to34.41°N, in which Jiangsu was the new added areas of suitable distribution. Similarly, the range for the suitable distribution of B. minax has little changed in2020, but the northern boundary for B.minax extend to35.26°N. As a result of climate global warming, the range for the suitable distribution of B.minax is projected to extend further northward as cold stress boundaries recede, suggesting that cold stress is likely to be the critical range-limiting factor.(2) Change trend of the predicted suitable distribution of Bactrocera dorsalis. The range for the suitable distribution of B.dorsalis was limited to97.53-121.97°E,18.25～31.38°N in China, including Guangdong, Guangxi,Yunnan, Guizhou, Sichuan, Chongqing, Hunan, Jiangxi, Fujian, Zhejiang and so on during1961-1990. The range for the suitable distribution of B. dorsalis has little altered during1981-2010, but the northern boundary for B.dorsalis broadened to31.98°N, in which Hubei was the new areas of suitable distributions. Likewise, the range for the suitable distribution of B.dorsalis has little changed during1981-2010, but the northern boundary for B.dorsalis extend to33.01°N. Owing to climate global warming, the range for the suitable distribution of B.dorsalis is projected to extend further northward as cold stress boundaries recede, which demonstrates that cold stress could be the critical range-limiting factor.2. The design and implement of monitoring and warning system of the citrus fruit flies based on WebGISASP.NET, Silverlight, ArcGIS Server, SQL Server were used to design and establish the monitoring and warning system for the citrus fruit flies, and the system was integrated into the result of DYMEX. The monitoring for citrus fruit flies in Hubei Province was conducted to demonstrate the applicability and feasibility of this system, such as information management, monitoring data management, monitoring data analysis, and warning and so forth. Finally, it proves that this system can assist in developing efficient strategies to manage the monitoring for plant protection.