Integrated management of Planococcus kraunhiae (Kuwana) (Homoptera: Pseudococcidae) injuring Japanese persimmons

Planococcus kraunhiae is the most serious pest of Japanese persimmons. The pest has been controlled only by insecticide, but chemical control is not successful because of hidden pest habitat and too small size of hatching nymphs to find. Development of integrated management system of the pest is very important for persimmon growers in Japan. I studied natural enemies of the pest, side effects of chemical control to the natural enemies, and monitoring methods of seasonal hatching nymph by using artificial female sex pheromone of the pest to establish the integrated management system of the pest. 1. The natural enemy complex of P. kraunhiae was investigated in Fukuoka. I found 8 parasitoid species and 5 predator species, and that Allotropa subclavata, Anagyrus fujikona, Diadiplosis hirticornis were among the most common. 2. Some pesticides used in Japanese persimmon orchards, such as Synthetic pyrethroid, Neonicotinoids, Organophosphates are harmful to natural enemies and induce resurgence of P. kraunhiae. In treated wall contact test, IGRs and BT were not so harmful. According these results, I established natural enemies-friendly pest control system with non-harmful pesticides. It was revealed that this control system was more effective than conventional pest control systems and could reduce the number of pesticide splay and cost. The period of residual contact toxicity of synthetic pyrethroids and neonicotinoids other than acetamiprid were more than 2 weeks. The period of residual contact toxicity of organophosphates was different depending on the kind. The period was more than 2 weeks in prothiofos and fewer than 5 days in fenitrothion. 3. The integrated management system of P. kraunhiae with utilizing natural enemies was established by using more mild pesticide to All. subclavata. The system was as follows: (1) Chemical control was applied only for the over wintering and the first generations of P. kraunhiae, and after its second generation was controlled by natural enemies, instead of insecticide, (2) Use more mild insecticide for other pests as possible, (3) Use neonicotinoids, instead of synthetic pyrethroid, in the year when Plautia stali invaded from outside the persimmon orchards and became serious pest. This control system can reduce time and cost of persimmon farmers than the conventional control system with only insecticide. 4. Direct whole trees splay of insecticide was not good for natural enemies even in the case of neonicotinoids. To improve application methods of such harmful insecticides, I tried direct application method of neonicotinoids on the trunks of Japanese persimmon. In this method, dinotefuran water-soluble mixed with thiophanate-methyl paste or water was applied to tree of Japanese persimmon at high concentrations before April. P. kraunhiae nymphs of over wintering generation were controlled in April when they start to suck tree sap. This method has no effect for All. subclavata. In addition, removing flayed barks perfectly to woody part before applied, apply extensively not only trunk but also bough, avoid removing by the rain as possible. 5. It was developped that prediction approach of hatching time of P. kraunhiae first generation that is most sensitive by peak of male of P. kraunhiae on pheromone-trap, combined artificial female sex pheromone of P. kraunhiae (major component: 2-isopropyliden-5-methyl-4-hexen-1-ylbutyrate) and sticky boad, and average temperature. This prediction approach is precision, so it is expected to extend control effect of applied insecticide on P. kraunhiae. 6. I demonstrated that a synthetic disruptet the mating of P. kraunhiae. In Japanese persimmon orchards (4～5a), 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 at 4 experiments for 3 years. 7. I previously discovered that (2,4,4-trimethyl-2-cyclohexenyl)-methyl butyrate (cyclolavandulyl butyrate, CLB) is an attractant for the maealybug-parasitic wasp Anagyrus sawadai. This wasp is not likely to parasitize P. kraunhiae under natural conditions. In this study, I showed that this ‘non-natural’ enemy wasp can parasitize P. kraunhiae in the presence of CLB in field experiments. Moreover, CLB attracted another minor parasitoid, Leptomastix dactylopii, which also parasitized more P. kraunhiae in the presence of CLB. In addition, CLB successfully controlled the population density of P. kraunhiae in the next generation at 4 experiments for 3 years in Japanese persimmon orchards. By generalizing these results, it was expected that injury by P. kraunhiae and insecticides applying time were reduced. Reducing insecticide applying time brings some good results that avoidance lowering insecticide sensitively, relief environmental load, satisfy consumer needs.