Oriental persimmon, Diospyros kaki Thunb., endemic to East Asia is one of the major fruit crops in Korea. We conducted the faunal survey of mites on persimmon trees in Korea from June to September 2006, especially focusing on herbivorous and predacious mites. Mites of Tetranychidae and Tenuipalpidae were dominantly collected as herbivores, while those of Phytoseiidae and Stigmaeidae were predominant as predators. All identified tenuipalpid mites were Tenuipalpus zhizhilashviliae Reck. Most of the collected tetranychid mites were found to belong to the genus Tetranychus. To clarify the species identity, additional collections of tetraychid mites during summer 2007 on sweet persimmon were made. The mites were identified as Tetranychus urticae Koch. Four phytoseiid species, Neoseiulus womersleyi (Schicha), Amblyseius eharai Amitai and Swirski, Phytoseius (Dubininellus) rubii Xin, Liang and Ke and Typhlodromus (Anthoseius) vulgaris Ehara were collected. Among them, A. eharai was the most dominant species.
Seventeen populations of two spotted mites (TSM) were observed 3 times per month from May to October to figure out their fluctuations at the site of individual farmer’s orchard from Sacheon, Sancheong, and Jinju in Gyeongsangnam- do and Gwangyang, Gurye, and Suncheon in Jeollanam-do. Among them, only 2 sites were properly managed, 5 sites were required to control but the farmers had little information on the mite and its damage, though 10 orchards were not in jeopardy. Number of TSM reached more than 400 at its maximum when 100 leaves were randomly observed at orchards from Sacheon, Okgok, and Muncheok, showing remarkably discolored leaves.
For the control of TSM in fields by chemical means, it was tried to select an effective miticides in persimmon fields. Control activity of spiromesifen 20SC showed 99.0% and 98.1% and the activity of acequinocyl 15SC showed 90.8% and 99.0% in Jinju and Sacheon at 20 days after treatment, respectively.
It was tried to understand the cause of the fluctuations of TSM populations on the viewpoints of pesticide spray, density of predacious mites, rainfalls, and weeds in the persimmon orchards. Various factors considered to contribute to the cause of population fluctuations, depending upon the situations of each orchard.
To develop as a potential resource of biological control agents, it was tried to find out winter spatial distribution and movement of Amblyseius eharai (Acari: Phytoseiidae) on persimmon trees in Korea using artificial materials. We attached Phyto traps and urethane foam on persimmon trees in early November 2007 in Sacheon, Korea to estimate overwintering ecology of the predominant phytoseiid species Amblyseius eharai on persimmon. Most of A. eharai were found on the samples of branches, such as pedicel. In early spring, A. eharai was abundantly collected in the weekly and long-term traps before the leaf extension of persimmon trees, which additionally enhanced the possibility that A. eharai overwintered on the trees.

• Bu-Keun Chung(Gyeongsangnam-do Agricultural Research and Extension Services)
• Mitsuhiro Kawashima(School of Bioresource Sciences, Andong National University)
• Chuleui Jung(School of Bioresource Sciences, Andong National University)