초록
고추와 사과에서 분리한 20개와 14개의 탄저병균 중에서 2001-45가 스테롤 생합성을 저해하는 살균제에 대하여 저항성 균주로 판명되었다. 2001-45는 myclobutanil, tebuconazole, hexaconazole, nuarimol 등에 대하여 153.5, 42.7, 34.0, 17.1 $\mu\textrm{g}$/ml로, 실험에 사용한 다른 탄저병균들 보다 높은 EC$_{50}$ 값을 보이며, 서로간에 교차 저항성을 나타냈다. 하지만 prochloraz(스테를 생합성 저해 살균제)에 대한 EC$_{50}$ 값은 0.07 $\mu\textrm{g}$/ml로, 감수성균인 2001-44와 JC24 보다도 감수성이 높았다. 20, 25, 3$0^{\circ}C$에서 스테롤 생합성 저해 살균제에 대하여 저항성인 2001-45의 균사 생장은 2001-44와 비슷하였으며, 또 다른 감수성인 JC24보다는 빨랐다. 그러나 PDA상에서의 포자 형성 능력과 고추열매에 대한 병원성은 JC24보다 현저하게 떨어졌다.
Among 34 isolates of Colletotrichum spp., 20 from red pepper and 14 from apple, only one isolate 2001-45 was identified as the isolate resistant to sterol biosynthesis inhibiting fungicides. EC$_{50}$ values of the isolate 2001-45 were 153.5, 42.7, 34.0, and 17.1 $\mu\textrm{g}$/ml for myclobutanil, tebuconazole, hexaconazole and nuarimol, respectively, The resistance factor of the isolate 2001-45 against the other isolate 2001-44 to 4 above fungicides was ranged from 17 to 57. However, EC$_{50}$ value of the 2001-45 for prochloraz was 0.07 $\mu\textrm{g}$/ml, which was lower than those of the 2001-44 and the isolate JC24. For the fitness test of the 2001-45, mycelial growth, sporulation on PDA and pathogenicity on fruits were investigated. No difference in mycelial growth was found between 2001-45 and 2001-44, but great difference in sporulation. No symptom was developed by 2001-45 even by wound inoculation of pepper fruit. Therefore, this study indicated that the isolate 2001-45 was inferior to the other isolates in the fitness, although the isolate 2001-45 was highly resistant to sterol biosynthesis inhibiting fungicides.