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Abstract

The density of overwintering Plautia crossota stali Scott in fallen leaves changed similarly in seven districts of Wakayama Prefecture, showing a remarkable peak in 1996. There was a highly positive correlation between the number of airborne pollen of sugi (Cryptomerica japonica D. Don) and the density of P. crossota stali overwintering in fallen leaves. There also was a highly positive correlation between the number of airborne sugi pollen and the number of light trap catches of P. crossota stali and Glaucias subpunctatus (Walker) in April–July of the following year. Since the overwintering density of the two stink bugs seemed to depend on the number of airborne sugi pollen, which is closely related to cone production, the number of airborne pollen is considered to be a useful index for forecasting the population densities of these two stink bugs in the following spring-summer season.