We demonstrated that a synthetic sex pheromone, 2-isopropyliden-5-methyl-4-hexen-1-yl butyrate, disrupted the mating of the Japanese mealybug Planococcus kraunhiae (Kuwana) (Hemiptera: Pseudococcidae). The synthetic pheromone was impregnated into grey rubber septa. In the presence of the synthetic pheromone, the copulation rates of reared P. kraunhiae were significantly decreased in a plastic case (diameter: 8 cm, height: 6 cm), an insect net cage (each side: 95 cm), and a small scale orchard (9 m2). In Japanese persimmon orchards (4~5 a), the dispersion of high concentrations of the synthetic sex pheromone disturbed male orientation, leading them towards the pheromone traps, and consequently reduced the number of females that copulated. In the persimmon orchard, mating disruption based on the synthetic pheromone successfully controlled the population density of P. kraunhiae in the next generation.
