Abstract
There were two outbreaks of Locusta migratoria on the first and second islands of the Kansai International Airport in 1994–97 and 2007, respectively. The characteristic two-toned pattern of black and orange colors in the hopper stage in phasegregaria was observed during the infestation. In 1995 and 2007, the locust population peaks were estimated at 13.4 million and 38.8 million, respectively, using the line-transect and quadrat methods, and the population was managed with fenitrothion EC. Increase in natural enemies, such as Entomophthora grylli and Latrodectus hasseltii, curbed both locust outbreaks. We hypothesized that the outbreaks were caused due to the infestation of some locust adults on reclaimed islands with a small number of natural enemies. The locusts were found mainly on the northwest of the islands and were thought to be caused by the south to southwest winds from June to September on the islands. L. migratoria is mainly bivoltine with embryonic diapause, but some individuals of the species hibernate during the adult and hopper stages on the islands. We adopted the following strategy for locust population estimation and management of the outbreak: (1) rapid estimation of the population, (2) mapping of the results to develop a perspective, (3) spraying the locusts from high to low densities, (4) evaluating the effectiveness of the control measures by rapid estimation of the locust population (similar to step 1), (5) repeating steps 1–3 in a cyclic manner, (6) pesticide suppression to preserve natural enemies in low-density areas. The locusts were sprayed to decrease the population from 38.8 to 0.14 million in 9 days on the second island from June 11 to June 19, 2007.
