2018 年 64 巻 p. 55-60
The effect of mating disruption to the Japanese mealybug, Planococcus kraunhiae, for two cropping years on its population density and damage on fruits in Japanese persimmon orchards was examined. Mating dispensers (MD) containing 50 mg of 2-isopropylidene-5-methyl-4-hexen-1-yl butyrate, which is identified as a sex pheromone component of P. kraunhiae, were installed in two orchards in early April of each year at a density of 50-100 dispensers per 1,000 m2. In the first year, when population density of overwintering P. kraunhiae was high (2-4 individuals per twig), the MD treatment reduced the density of the second and third generations of P. kraunhiae with fewer chemical spray applications than control fields although damage on fruits was severer in MD-treated fields, probably because of high density of the first generation of P. kraunhiae in June in the MD-treated fields. In the second year, both densities of P.
kraunhiae population through the year and damage on fruits could be suppressed by the MD treatment. These results indicate that the two-year continuous MD treatment is effective for reducing damage on persimmon fruits in the second year by suppressing population density of P. kraunhiae.