Numerical model simulations of brown planthopper Nilaparvata lugens and white-backed planthopper Sogatella furcifera (Hemiptera : Delphacidae) migration

This paper reports on the performance of an atmospheric numerical model cal led BLAYER which has been adapted to forecast the movement of migrant brown planthopper Nilaparvata lugens (Staringl) and white-backed planthopper Sog atella furcifera (Horvarth) populations from China to Korea. Comparison of model forecasts with trapping data for the 1987 and 1988 migration seasons indicated: (i) that the model is capable of successfully simulating the mov ement of planthoppers to Korea; (ii) that the model has sufficient detail t o simulate insect movement into different regions of Korea; (iii) the sourc e region for early season migrants is most likely to be south-eastern China (i.e. south of 25 degrees N and east of 115 degrees E); (iv) later season migrants may not necessarily always originate from an expanded northward re gion (south of 30 degrees N); (v) the flight level of migrants may vary fro m about 500 to 2000 m altitude from one migration episode to another; and ( vi) flight times ranging between 24 and 45 h are required to explain the mi gratory influxes. The results reported here have led to BLAYER forecasts of planthopper migration being produced on an operational basis within Korea.