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To investigate occurrence of root-knot nematode (RKN) in plastic house of central area of Korea, 132 soil samples were collected in cucumber, water melon, tomato, red pepper and strawberry fields from 2013 to 2015. Among 132 soil samples, 65 soil samples (49%) were infested with RKN and mean density of RKN was 178 second-stage juveniles per 100 cm 3 soil (min. 1 ~ max. 3,947). The frequency of RKN by regional was the highest in Chuncheon with 80%, followed by Cheonan (68%), Nonsan (36%), Buyeo (33%) and Yesan (30%). The frequency of RKN by crops was the highest in tomato with 83%, followed by cucumber (61%), strawberry (41%), red pepper (30%), watermelon (26%). To identify the species of RKN, fifteen populations were selected for representative populations. As a phylogenetic analysis of 15 populations, southern root-knot nematode (Meloidogyne incognita), peanut root-knot nematode (M. arenaria) and northern root-knot nematode (M. hapla) were identified with 47%, 20% and 33% ratio, respectively. In crops, M. incognita, M. arenaria and M. hapla were detected in tomato, M. incognita and M. arenaria were detected in cucumber and watermelon, and M. hapla was detected in strawberry and lettuce. Thus, there should be a continuous management to major species of each crops to prevent dispersal of RKN damages.

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To investigate the effects of Brassicaceae cover crops on clover cyst nematode, Heterodera trifolii, 10 cultivars consisting of six of oil radish and four of white mustard were planted in the nematode infected field at Jeongseon city. Two months after planting, the cover crops were plow down and incorporated into the soil using rotavator, decomposed for 1 month, then transplanted kimchi-cabbages. After 70 days, the density of eggs inside of the cyst and the number of females in the soil were examined. As a result, the reproduction rates of eggs in each plots of Adios and Anaconda cultivars, which were 0.04 and 0.02, respectively, were greatly reduced. The number of females in the plots of above two cultivars showed means at 2.5 and 3.5 per 300 cm 3 soil, which were lower than those of other plots. In addition, fresh weights of three plants in the two plots, which were 7.67 and 7.35 kg, were significantly higher than that of the control plot. Collectively, these results suggest that the two cultivars of Brassicaceae cover crops, Adios and Anaconda, could be used for reducing the cyst nematode density.