청양 지역 고추와 구기자에서 분리한 탄저병균의 동정, 균학적 특징 및 살균제 저항성

Abstract

It was conducted to identify all 47 isolates obtained from infected fruits of pepper and boxthorn, and to investigate the mycological characteristics and the response to fungicides. All of 11 isolates from pepper were identified as Colletotrichum acutatum included into A2 group. Among 36 isolates from boxthorn, 14 isolates were identified as C. gloeosporioides, and the others were done as C. acutatum, which were composed as A1 group with 15 isolates and A3 with 7 isolates. After incubating the isolates on PDA at 25 o C for 10 days, the colony color of C. acutatum was greyish white, while that of C. gloeosporioides was orange at center of colony and was gradually turned into an greyish white to the periphery. The rate of conidia showing ellongated ellipsoidal shape with round ends was over 95% in C. acutatum isolated from pepper. However, C. acutatum isolated from boxthorn produced ellongated ellipsoidal conidia with the rate of 75%, and the others were pointed at one or both ends. Regardless of species of Colletotrichum, all isolated used in this study was showed an optimal temperature at 25 o C. EC50 values of all isolates of Colletotrichum spp. to 2 fungicides as carbendazim and the mixture of carbendazim and diethofencarb was investigated by an agar dilution method. With C. acutatum isolates from pepper belonged to A2 group, the mean of EC50 value to carbendazim and the mixture of carbendazim and diethofencarb was 0.68 and 3.16 µg/ml, respectively. In the case of C. acutatum isolates from boxthorn, which were divided into 2 groups as A1 and A3 group, that to carbendazim was 0.21 at A1 and 0.24 µg/ml at A3, while that to the mixture was 1.52 and 3.35 µg/ml. Isolates of C. gloeosporioides showed the mean of EC50 value was 0.12 µg/ml to carbendazim and 0.92 µg/ml to the mixture. The value of resistant factor was higher in the isolates of C. acutatum obtained in boxthorn than those from pepper.