The Regional Landing Patterns Of Brown Planthoppers (Nilapavata Lugens)

Using the geographic information system software ArcGIS8.3(ESRI company), thechina digital map(1 : 4,000,000) and the light-trap data of brown planthoppers from May toJuly in 1995,1997 and 1998 which were collected from rice planthoppers surveillancestation in China and the corresponding wind field data for 850hPa isotonic level at 08h(BJT)and the everyday rainfall data from Chinese Meteorological Bureau between 1986 and 2000were overlapped and the relationship of them were studied.The results indicated that the non-succession of transporting air current for 850hPaisotonic level at 08h(BJT) in 1995 had very little influence on the landing place of BPH,only two cases(9 percent in 1995) showed that landing place were behind the wind shiftand other twenty cases (91 percent in 1995)showed that transporting air current weresuccessive. The transporting air current for 850hPa isotonic level at 08h(BJT) in 1997 had alittle influence on the landing place of BPH, four cases (33 percent in 1997) showed thatlanding place were behind the wind shift or in the center of the Depression system. Thetransporting air current for 850hPa isotonic level at 08h(BJT) in 1998 had obviousinfluence on the landing place of BPH, seven cases (54 percent in 1998) showed thatlanding place were in the center of the Depression system.The rain caused by the Sub-tropical High and Depression systems was the mostimportant factor which influenced the landing place of BPH in 1995 and 1997. There weresixteen cases(72.7 percent in 1995) in 1995. The rainfall less than median rain were fourcases(18.1 percent), between median rain and heavy rain were six cases (27.3 percent),between heavy rain and hard rain were six cases (27.3 percent). The most landing placewere in the center or south of the rain band, the landing place of BPH also moved the samewith the rain band. There were many BPH landing at the Yangtze River valley after theperiod of mould rain. It was because the Yangtze River valley was controlled by thesub-tropical high and there were downward air current which influenced the BPH toland(six cases, 27.3 percent in 1995), and it was the important factor which caused the greatdamage to rice in this area. There were ten cases (83.3 percent in 1997) in 1997. Therainfall less than median rain were three cases (25 percent), between median rain and heavyrain were one case (8.3 percent), between heavy rain and hard rain were six cases (50percent). The most landing place were in the center or south of the rain band. There weremany BPH landing at the Yangtze River valley when rain band moved north after July 16th.It was because the Yangtze River valley was controlled by the sub-tropical high(two cases,16.7 percent in 1997) and there were downward air current which influenced the BPH toland, and it was the important factor which caused the great damage to rice in this area.The rain caused by Depression system was the most important factor which influencedthe landing place of BPH in 1998. There were twelve cases(92.3 percent in 1998).The rainfall less than median rain were five cases(38.5 percent), between median rain and heavyrain were two cases(15.4 percent), between heavy rain and hard rain were two cases(15.4percent), more than hard rain were three cases(23 percent). The most landing place were inthe center or south of the rain band and the Depression system. There were one case whichcontrolled by the sub-tropical high(7.7 percent in 1998). Lots of BPH which landed inGuizhou Province and the south of Anhui Province were the important factor which causedgreat damage to rice in the south west of China and the south of the Changjiang River in1998.