To make certain of the white tip infection on rice, nematodes isolated from the rice seeds grown at Chongdo-goon Isu-myun and Kimje-goon Chooksan-myun were artificially inoculated and their pathway was studied. Also, studies were made for the hot water seed treatment as a measure of white tip control at different levels of water temperature and their germinablity was checked. The results are summarized as follows; 1. Causal nematodes survive in the paddy soil and cause white tip year after year. 2. Causal nematodes can survive in the rice seeds as long as the seeds loose their germinability. 3. Causal nematodes can disseminate throught the irrigation water. 4. Causal nematodes can disseminate through the soil move from a place to other place. 5. Causal nematodes can infect all of the parts of the rice and they can disseminate through any of the parts of rice. 6. The hot water treatment at 5$0^{circ}C$ for 60 minutes were not effective controlling causal nematodes. But, either treatment of at 55$^{circ}C$ for 15-20 minutes or at 6$0^{circ}C$ for 10-15 minutes were effective and germination of seeds was not affected.