지역 및 품종에 따른 벼 이삭누룩병 발생과 약제방제 효과

Incidence of Rice False Smut Caused by Ustilaginoidea virens in Different Geographic Regions and Cultivars, and Its Chemical Control

2000년에 전국적으로 이삭누룩병이 발생한 포장의 비율은 7.5%이었으며, 지역별로는 충북이 13.7%로 가장 높았고 전남이 1.5%로 가장 낮았다. 벼 품종별로는 남천벼가 가장 감수성이었고 흑진주벼는 1999년과 2000년에 전혀 발생이 되지 않아 가장 저항성인 것으로 조사되었다. 이삭누룩병 약제방제 선발 시험결과 터부코나졸 수화제의 방제가는 83.0% 이상으로 가장 우수하였고, 훼림존 성분이 함유된 두 약제도 방제가가 60.9%∼75.9%로 나타났다. 남원 지역의 포장에서 이삭누룩병 발생이 높은 원인은 일조부족 및 강우량이 많아 발병이 조장된 것으로 분석되었다.

Currently the rice false smut caused by Ustilaginoidea virens (Cooke) Takah. has occurred widely in Korea. A survey on the disease incidence at rice fields in 8 inland provinces was carried out in 2000, showing that the disease occurred at 104 (7.5%) out of 1,152 rice fields examined, ranging from 1.5% to 13.7% in provincial average. It was found that the disease incidence was greatly affected by local weather conditions and rice cultivars. In case of the most susceptible cultivar Namchunbyeo, the disease incidence was only about 1.3% in Icheon, while it was over 20% in Namwon which had weather conditions of the shorter sunshine period (about 64%) and the higher amount of precipitation (about 130%) during the rice cultivation than Icheon. In Icheon, artificial inoculation of the pathogen failed to induce the disease, probably because of the weather conditions unfavorable to the disease development, which also suggests that its incidence may be dependent on the weather conditions. Susceptibility of rice cultivars to the disease varied greatly; eight resistant cultivars including Heukjinjubyeo were not damaged by the disease, but 2 cultivars including Geumnambyeo and Namchunbyeo were severely damaged, having more than 20% of the disease incidence. Among chemicals tested fur the control of the rice false smut tebuconazole WP showed the highest control efficacy of 83∼88% on cvs. Geumnambyeo and Namchunbyeo. Other chemicals such as azoxystrobin WP and ferimzone WP also effectively suppressed the disease development in the field trials.