Damages by Tyrophagus spp. (Acari: Acaridae) on horticultural crops were newly observed in recent years especially in organic culture greenhouses in Korea. The crops damaged by the mite species were Spinacia oleracea L. (spinach), Cucumis sativus (cucumber), and Phalaenopsis schilleriana (orchid). The spinach inner leaf growth was halted affected by the feeding of Tyrophagus similis at the early stage of the shoot emergence. The young leaves of the spinach bud had small holes and the leaves were deformed as they grew up. The surface of young cucumber fruits became shiny and soft at the early damage stage and the damaged surfaces became corky as the plants grew up. The mite from cucumber was identified as Tyrophagus neiswanderi Johnston & Bruce. In phalaenopsis orchid, the flower buds became yellow and dropped and the lower side of the leaves had white spots. The damages were caused by Tyrophagus putrescentiae.

• Jae A Jung(National Institute of Horticultural & Herbal Science, RDA)
• Myoung Rae Cho(National Institute of Horticultural & Herbal Science, RDA)
• Hyeong Hwan Kim(National Institute of Horticultural & Herbal Science, RDA)
• Taek Jun Kang(National Institute of Horticultural & Herbal Science, RDA)
• Kyeong Ran Do(National Institute of Horticultural & Herbal Science, RDA)
• Jong Ho Lee(National Plant Quarantine Service)