The root-lesion nematode Pratylenchus spp. is the most important plantparasitic nematode due to its worldwide distribution, wide host ranges, and migratory endoparasitic characteristics. One population of Pratylenchus collected from the giant pussy willow (Salix chaenomeloides Kimura) in the Andong area as part of a nematode survey in Korea was characterized morphologically and by molecular methods. The analysis of morphological measurements and morphometric characteristics, as well as DNA sequencing of the rRNA large subunit (LSU) D2/D3 expansion segments and the internal transcribed spacer (ITS) gene sequence, confirmed the identity of this population as P. hippeastri. This study is the first report of P. hippeastri associated with Salix chaenomeloides in Korea and worldwide. Further studies on distribution and pathogenicity in different P. hippeastri host crops, such as grapevines, strawberries, and apples, are necessary. The taxonomic keys to 16 Pratylenchus species in Korea are provided.

We reported a new white soybean cyst nematode, Heterodera sojae in 2016. This species is closely related to H. glycineswhich has the same host plant. Morphological observations of the cyst, female, male and second-stage juveniles indicatedthat this species is differed from those of H. glycines. Cysts of H. sojae appeared more round, shining and darker thanthat of H. glycines. The distribution of this new cyst nematode in soybean field in Korea is unknown yet. In 2016, 270soil samples were collected from soybean fields and examined the existence of H. glycines and H. sojae. Total of 111samples (41.1%) contained cysts. Among them 77% were H. glycines and 23% were H. sojae. Our results suggest thatextensive researches are required for white soybean cyst nematode.

Plant-parasitic nematodes causes yield losses of more than $100 million per year in the world. Among them, soybeancyst nematode (Heterodera glycines Ichinohe) causes the greatest yield loss to soybean compared to any other pest worldwide.SCN causes yield reductions by feeding on plant nutrients, retarding root growth and inhibiting Bradyrhizobium japonicum(Kirchner) Buchanan nodulation. The primary methods for controlling SCN include planting resistant cultivars and rotationwith nonhost crop. In order to control SCN, we should be breeding resistant soybean cultivars which has resistant genefor this pest. The research that can minimize the damage of the soybean yield is still insufficient, comprehensive andsystematic research is urgently required. Current researches in our lab are discussed.

This study is the identification of root-knot nematode (RKN), Meloidogyne hapla, from strawberry in Korea using molecular analyses. Strawberry plants showed localized stunting and galled roots. Molecular analyses of COⅡ/lrRNA, 28S rDNA D2-D3 segment and internal transcribed spacer (ITS) region were employed for the identification of Meloidogyne spp. Polymerase Chain Reaction (PCR) amplification of COⅡ/lrRNA region produced a single fragment ca 528bp. Restriction digestion of the amplified PCR products with Dra1 enzyme produced two fragments at 200 and 250bp indication M. hapla. 28S rDNA D2-D3 segment and ITS were cloned and sequenced. 28S rDNA D2-D3 segment and ITS region produced a single fragment of 1004bp and 560bp, respectively. In BLAST search in Genbank, all sequences accord with other known M. hapla. As a result, all of the RKN samples were M. hapla. This study suggests that the dominant species of RKN on strawberry is M. hapla in Korea.

For management of soybean parasitic cyst nematodes, this study was conducted to investigate the resistance of the Korean soybean cultivars to HG type 2.5.7 of Heterodera sojae. Among the 44 Korean soybean cultivars, there was only one resistant cultivar ‘Namcheon’. ‘Sobaeknamul’, ‘Socheng No. 2’, ‘Pungsannamul’, ‘Cheongja’, ‘Miryang’ and ‘Daewon’ were moderately resistant to HG 2.5.7 of H. sojae populations. Eleven cultivars including ‘Paldal’ were moderately susceptible and the other cultivars were susceptible. Therefore, soybean cultivar ‘Namcheon’ should be cultivated in H. sojae infested fields, until varieties resistant against Heterodera species are more developed or identified. Moreover, ‘Namcheon’ is not recommended for cultivation because very weak to soybean mosaic virus, and it will be a candidate with resistant cultivar breeding resource.