Monitoring Of The Brown Planthopper Nilaparvata Lugens, The White-backed Planthopper Sogatella Furcifera And The Rice Leaf Roller Cnaphalocrocis Medinalis With A Millimetric Scanning Entomological Radar In Guangxi

The Brown Planthopper Nilaparvata lugens (BPH), the White-backed Planthopper Sogatella furcifera (WBPH) , and the rice leaf roller moth, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae),both reproduce successfully on rice and migrate long distances, They are the most important pests of irrigated rice throughout much of China. Recently , severe losses have been caused by pests in southern China, which threaten the increased production of high quality ,high value rice in this area. In order to explore the pests population dynamic in the aerial distribution , and the trajectory of immigration and emigration, we conducted this experiment by using an 8.0 mm wavelength scanning entomological radar, a searchlight trap and a ground light-trap, ovary development, aerial netting , which obtained insects flight parameter. comprehensive Analysis a relationship between immigration and emigration of pests and atmospheric dynamical fields, which based on exchanged information about pest dynamics in various regions and lower-Level and mesoscale flow filed. We have initially established emigration forward trajectories and immigration backer trajectories of pests.In Xing'an, there are variation of number of species and catches daily caught in the light-trap through seasons. From June to September , number of insect's species and catches is more high than in October . There is a high consistency between the radar echoes and catches in searchlight trap , which reveals that the millimetric scanning radar can reflect well insect population dynamics in the air.From May to October in 2007, There have five significant flight period of WBPH and BPH in light-traps. However, there are different the population dynamics . The time that WBPH being catched in light-trap more early than BPH, but we can see number of BPH more than WBPH with time process and the number of WBPH has decreased. Planthoppers summer peak number was significantly higher than that fall. Typical planthoppers'immigration and emigration has been observed by radar. In summer, When planthoppers emigrated, most of female adults'ovarian development are two grade. In the late afternoon, the planthoppers have taken off for half an hour. Radar registered the take-off of the planthoppers between 19:00 and 19:45 h, at 19:00 h the first hint of this speckle on the PPI appeared. The speckle thickened quickly during the next twenty minutes or so, reached maximum density at 19:20 and 19:45, Later in the evening, the vertical profile of insect density became stratified. Planthoppers flight altitude can reach 2200 m , mainly in the 1500²000 m. The dawn emigration thus took place, but the densities are less than that at dusk.Forward trajectories were constructed by using Hysplit₄ patterns in order to estimate possible sink areas of the planthopper observed taking off from Xing'an at dust. A flight duration of 12 h and 24 h was assumed, they would have reached rice-growing areas in Hunan and Jiangxi, or even part of Hubei and Anhui. In autumn, planthoppers affected by the tropical storm , there are sudden increase catches in light-trap in the same period in Hubei, Guangdong, Jiangxi and Guangxi. The back-trajectory indicated that the source of these insects in northeast Guangxi from Hunan and Hubei.From May to October in 2007, There have two significant flight period of the rice leaf roller catches in light-traps, inside June 9¹0 and September 5⁸. However, radar observed last one population dynamics, most of female adults'ovarian development are low-grade. It show that most of pests have immigration, Radar registered the take-off of the rice leaf roller between 19:10 and 20:00 h, and flight altitude can reach 800 m . Forward trajectories were constructed by using Hysplit₄ patterns in order to estimate possible sink areas of the rice leaf roller observed taking off from Xing'an at dusk. A flight duration of 6 h , 12 h and 24 h was assumed, they would have reached rice-growing areas in southwestern Guangxi, but the rice leaf roller would stop to emigrate by the strong airflow impact of the southeast on 7 September.The flight parameters of planthopper and rice leaf roller would provide a scientific and effective basis. for the next step on its migration laws and acts of migration.