Mesoscale Analysis On Source Areas And Landing Mechanisms Of Sogatella Furcifera (Horv(?)th) And Nilaparvata Lugens (St(?)l) In Guangdong Province

Guangdong is the one of the most important rice producing areas in China,the index of rice multiple cropping is very high.In recent years,because of its long distance migration behavior,the rice planthopper including the white-backed planthopper,Sogatella furcifera(Horvdth)and the brown planthopper Nilaparvata lugens(Stal),have caused serious damage in the rice industry in China.Since 2008 years,the damage areas in Guangdong province caused by the rice planthopper continue to increase.Guangdong's location is extremely important due to its first station of the rice planthopper migration overseas.At present,there was little study on mesoscale source areas of the rice planthopper in different partial and temporal conditions,while its's regional landing mechanisms in Guangdong had not study yet.So it is extremely urgent to realize detail offsite forcast by making mesoscale analysis on source areas and landing mechanisms of the rice planthopper in Guangdong province clearly.In this study,we conclude definite mesoscale source areas and landing mechanisms of the rice planthopper in Guangdong province,study the its continuous outbreaks relation with meteorological factors.The main contents are as follows:1.The source areas and landing mechanisms of the early immigrant WBPH in west Guangdong.We studied the migration rules of early immigration WBPH of 6 stations in west Guangdong province from 2006 to 2014(Mar.to Jun.),the results were as follows:(1)The source areas of early immigration WBPH are Hainan,northern and mid Laos,northeastern Thailand,northern and mid Vietnan in March.The source areas are Hainan,mid Laos,mid Vietnan in April.The source areas are southern China(Hainan,Guangdong and Guangxi)in May.The source areas are Hainan,northeastern Thailand,northern and mid Laos,mid Vietnan in June.A certain frequency of southern wind,southwestern wind and southeastern wind carried the population of WBPH from indochina to southern China from March to June.(2)The terrain of western Guangdong is complex,we study the early immigration WBPH in Leizhou to realize the landing mechanisms,the low temperature and heavy rain were the key factors to affect the concentrated landing of WBPH.2.Dynamics and population analysis of BPH in the late rice field in northern GuangdongThe autumn,from 2006-2012,the source areas of the autumn migration of the were studied by trajectory analysis based on the daily light-trap catches.We use NCEP-NCAR reanalyzing data with GrADS in order to conduct the landing mechanism of the brown planthopper in autumn 2011.the results were as follows:(1)The immigrantion peaks of WBPH in the late rice appear from early and middle September to late October.The source areas of the brown planthopper in northwestern Guangdong were mainly located in southern Hunan,southern Fujian,jiangxi and northern Guangdong.The source areas of the brown planthopper in northwestern Guangdong were located in southern Fujian,southern jiangxi and northern Guangdong.The different terrain resulates in the different distribtion of BPH that landed at two place.(2)We use GrADS to analysis the landing mechanism of the brown planthopper in autumn 2011 and the result tells that the airstream of low lever jet carried BPH to the south,the wind shear and heavy rainfall were the key factors to affect the concentrated landing of BPH.(3)The later August and earlier September,the later September and earlier October were the two autumn migration peak of BPH from northern areas to northern Guangdong in 2011.The rice plant grow from tillering stage to heading stage,two autumn migration peak aggravated the damage of the late rice field.3.The influence of typhoon transit on planthopper migration patterns in Guangdong ProvinceWe studied the influence of typhoons(1208 Vicente,1111 Nanmadol)in 2011 and 2012 on migration patterns of the rice planthopper associate with its daily light-trap catches in Guangdong.And the results were as follows:(1)When typhoon Vicente landed in Guangdong,the certain southern wind influence the rice planthopper's diffusion from the near station in northern Guangdong;the result tells that the airstream of low lever jet appears in indochina,the southern wind bring the rice planthopper from Vietnam to western Guangdong and Leizhou peninsula.After Vicente passed,with the deterioration of rice plant in northern province such as Jiangxi,Zhejiang,Hunan,Anhui,associate with the certain northern wind bring rice planthopper from north areas to south;Before typhoon Nanmadol landed,the certain southern wind bring rice planthopper from south areas to north inGuangdong;when Nanmadol gradually move westward landed in Fujian,the southeastern wind bring rice planthopper from north areas(Jiangxi,Zhejiang,Fujian)to western Guangdong;when Nanmadol gradually move to south(the northern Guangdong located in the typhoon center),whice is helpful for rice planthopper's diffusion from the near station in northern Guangdong.(2)Before and After typhoon landed,the wind shear and heavy rainfall were the key factors to affect the concentrated landing of the rice planthopper.(3)The high frequency of typhoons that create high temperature and high humidity environment was conducive to outbreaks of the rice planthopper.