SEASONAL OCCURRENCE AND ASPECTS OF ROOT-KNOT NEMATODES IN MAJOR KIWIFRUIT CULTIVATION AREAS OF KOREA

This study was conducted to investigate the ecological environment of root-knot nematode (Meloidogyne spp.) and the damage caused in kiwifruit cultivation areas around Jeonnam, Gyungnam, and Jeju provinces from 2001 to 2004. Root-knot nematodes were found in all investigated areas and the dominant species was Meloidogyne hapla. The number of 2^nd stage larvae of M. hapla in kiwifruit orchards increased from mid-late September and reached a maximum density in winter, but decreased in summer. When the larval density was more than 3,000 (per 300 g soil unit), the kiwifruit root damage was clearly visible (more than 70 root knots/g root weight). Kiwifruit growth was severely reduced when the larval density increased to over 10,000 (at least 100 root knots/g root weight). The vertical distribution showed that 91% of nematodes existed within 30 cm of the soil surface.