Flight duration of the brown planthopper, <i>Nilaparvata lugens</i> (Homoptera: Delphacidae)

ABSTRACT. The brown planthopper, Nilaparvata lugens (Stål), is a major pest of rice in Asia. It is known to make wind‐assisted migratory flights each year to colonize the summer rice growing areas of China, Japan and Korea. Modelling windborne displacements between rice growing areas in Asia requires migratory behaviour and flight duration to be established for this insect. Field and laboratory observations suggest that N. lugens take‐off at dusk and that some continue flying for up to 24–26 h if the temperature is ≥ 17°C. Trajectories for 10 m above ground level and 1.5 km above mean sea level are used to identify possible sources and, hence, to estimate the flight times of N.lugens caught in nets on ships on the East China Sea in 1973 and 1981. Estimated flight times between the sources and the ships ranged from about 9 to 30 h. Results suggest that long‐distance migration can occur in surface winds, when they are strong, but that long‐distance migration is more likely at 1.5 km. When simulating windborne displacements of N.lugens , it can be assumed that in areas and at heights where the temperature is ≥ 17°C, some migrants will fly downwind for up to 30 h after a dusk take‐off. Others will fly for shorter periods, giving the population as a whole the opportunity to colonize all the rice crops flown over.