Abstract
In order to develop effective control methods for Bakanae disease caused by Gibberella fujikuroi (Saito) Ito during rearing of rice seedlings, we investigated the disease resistance of 15 rice varieties to G. fujikuroi and control effect of six seed disinfectants, and tried to improve the using methods of the seed disinfectants. Disease resistance was tested by investigating the disease incidence on each rice cultivar grown in rice seedling box infested with or not infested with G. fujikuroi at 30 days after sowing seeds and 20 days after heading date. The results showed that Hwayongbyeo, Dongjinbyeo, Hwoanbyeo, Nonghobyeo, Nampyeongbyeo, and Hwojinbyeo were resistant G. fujikuroi, meanwhile Keulubyeo, Sobibyeo, Odaebyeo, Junambyeo, Samchonebyeo, Sangjubyeo, and Hwabongbyeo were susceptible. Three seed disinfectants, prochloraz, fludioxonil, and carproamid + thiram + fludioxonil controlled Bakanae disease of rice very well, while bonomyl + thiram, thiophanate-methyl + thiram and thiophanate-methyl + triflumizole did not suppress the disease enough. Water temperature was turned to be an important factor for controlling the disease by treating seed disinfectants. Prochloraz showed 61% control value on the disease at $10^{\circ}C$, but it showed above 95% control value at the range of $30-35^{\circ}C$. It was confirmed that the control effect of seed disinfectants increased with increasing water temperature. Meanwhile soaking period of rice seeds in the suspension of seed disinfectants and chemical dosage had no high relation to control the disease. This results suggest that rice varieties, water temperature, and optimal selection of suitable seed disinfectants are very important to control Bakanae disease effectively.
벼 육묘기간 중에 발생되는 벼 키다리병의 방제법을 확립하고자 최근에 육성된 벼 품종별 발병 정도와 시판되는 종자소독제의 방제효과를 조사하였으며 종자소독시 약액의 온도, 처리시간 및 약량에 따른 벼 키다리병 방제효과를 조사하였다. 품종별 벼 키다리병 발생정도를 조사한 결과 화영벼, 동진벼, 호안벼, 농호벼, 남평벼, 호진벼 6 품종이 저항성 품종으로, 그루벼, 소비벼, 오대벼, 주남벼, 삼천벼, 상주벼, 화봉벼 7 품종이 감수성 품종으로 분류되었다. 종자소독제별 벼 키다리병 방제효과에 있어서 prochloraz, fludioxonil, carpropamid+imidacloprid+fludioxonil 등은 높은 방제 효과를 보였으나 benomyl+thiram, thiophanatemethy+thiram, thiophanate-metyl+triflumizole등은 방제효과가 저조하였다. 종자소독당시 수온에 따른 벼 키다리병 방제가는 $10^{\circ}C$에서는 61% 이었으나 온도가 높아질수록 상승하여 $30\sim35^{\circ}C$에서는 벼 키다리병을 $95\sim98%$이상 방제할 수 있었다. 그러나 종자소독시간과 약량은 벼 키다리병 방제에 크게 영향을 미치지 않았다. 따라서 벼 키다리병을 효율적으로 방제하기 위해서는 저항성이 강한 벼 품종과 효과가 우수한 종자 소독제 선정 그리고 종자소독시 적정수온을 유지하는 것이 중요한 것으로 나타났다.
