Insect Pest Problems of Sweet Persimmon in Korea

Of all the fruit trees grown in Korea, persimmon ranks the second in terms of acreage. Diseases and insect pests are important factors affecting persimmon production. Questionnaires to sweet persimmon growers indicate that the most serious insect pests is stink bugs (73% of the answers) followed by scale insects (19%). Most growers spray chemicals six to nine times a year to control those pests. Among scale insects, the grape-myrtle scale Eriococcus lagerstroemiae, horned wax scale Ceroplastes pseudoceriferus, and elongated cottony scale Phenacoccus aceris are of major concern. However, they seldom become serious in commercial orchards because of insecticide sprays. Machine oil spray during winter is necessary against the scales. Three species of stink bugs are important: brown marmorated stink bug Halyomorpha halys, brown-winged green bug Plautia stali, and bean bug Riptortus clavatus. They feed on fruits making them unmarketable. A Japanese gall-forming thrips, Ponticulothrips diospyrosi, found for the first time in Korea in 2000, is spreading throughout the southern part of Korea. Acreage of persimmon orchard damaged by the thrips was 446 ha in 2005. It feeds on young fruits and leaves of both sweet and astringent persimmons. Together with those insect pests, the basic ecology of other minor insect pests such as smaller clearwing moth Synanthedon tenuis and two-spotted spider mite Tetranychus urticae will be presented.