Long-term Forecasting Of The Early-season Immigration Of The Brown Planthopper In The Lower Yangtze River Valley

In china,brown planthopper(BPH),Nilaparvata lugens(Stal),is one of the most serious pests of rice in Lower Yangtze River Valley.The brown planthopper has moved to the rice growing area in the Lower Yangtze River Valley from the source area in June and July.Because of its long-distance migration,Interannual fluctuations of the occurrence of brown planthoppers in the Lower Yangtze River Valley is extremely high,and it is difficult to prevent and control effectively.However,the early-season immigration of brown planthopper is closely related to the degree of occurrence in the Lower Yangtze River Valley.Therefore,predicting accurately the early migration of brown planthopper in advance is very important for the control and population management of brown planthopper.In this paper,the light catches data of BPH of four stations in Dongzhi,Huizhou,Gouchun and Jiaxing and meteorological data from 1978 to 2018 were selected for research.The main research methods include correlation analysis,linear regression models,generalized linear models and other methods to analyze the effects of atmospheric circulation and the South China Sea summer monsoon and ENSO on the migration of brown planthoppers,and to find the early warning indicators of early immigration level of BPH,and to establish the prediction model for the early immigration of brown planthopper in the in southern Anhui province,Gouyou and Jiaxing,respectively.The main results were as follow:1.The relationship between the early migration of BPH in the Lower Yangtze River Valley,the early insect amount in source area and the climate(1)There was a significant positive correlation between the early-season immigration of BPH and the occurrence of brown planthopper in the field in the southern Anhui province,Gaochun and Jiaxing.(2)There was a significant positive correlation between the early-season immigration of BPH and the BPH amount in the northern Guangxi province at May.(3)The climate in July had a significant impact on the early-season immigration of brown planthoppers in the Lower Yangtze River Valley,especially the precipitation in the Lower Yangtze River Valley and its northern in July and wind field in the southeast China in July,while Vertical airflow in July only had little effect on the early-season immigration of brown planthoppers.2.Correlation of the early-season immigration of brown planthopper in the Lower Yangtze River Valley and the South China Sea summer monsoon and its implications for long-term prediction(1)There was a significant positive correlation between the onset time of the South China Sea summer monsoon and the early-season immigration of BPH in the southern Anhui province,Gaochun and Jiaxing.(2)The onset of the South China Sea summer monsoon has important impact on the precipitation in the Lower Yangtze River Valley and its northern regions in July and the wind field in the southeastern China,which ultimately affected the early-season immigration of brown planthoppers in southern Anhui province,Gaochun and Jiaxing.(3)The models based on the onset time of the South China Sea summer monsoon and the the BPH amount in the northern Guangxi province at May had a good predictive effect on the early-season immigration of brown planthoppers in southern Anhui province,Gaochun and Jiaxing.3.Correlation of the early-season immigration of brown planthopper in the Lower Yangtze River Valley and ENSO and its implications for long-term prediction(1)There was a significant positive correlation between ENSO and the early-season immigration of BPH in the southern Anhui province,Gaochun and Jiaxing.(2)The ENSO has important impact on the precipitation in the Lower Yangtze River Valley and its northern regions in July and the wind field in the southeastern China by affecting the onset time of the South China Sea summer monsoon and the intensity,location of Western Pacific Subtropical High,which ultimately affected the early-season immigration of brown planthoppers in southern Anhui province,Gaochun and Jiaxing.(3)The models based on the ENSO and the the BPH amount in the northern Guangxi province at May had a good predictive effect on the early-season immigration of brown planthoppers in southern Anhui province,Gaochun and Jiaxing.Compared with the prediction models based on the onset time of the South China Sea summer monsoon and the the BPH amount in the northern Guangxi province at May,the prediction accuracy of this model is higher.