辣椒炭疽病菌对嘧菌酯的敏感性测定

 从江苏和海南省随机采集分离获得45个辣椒炭疽病菌单孢菌株,根据孢子形态鉴定其病原菌为Colletotrichum gloeosporioides和C.capsici,其中C.gloeosporioides占总菌株数的64.4%.筛选出甘油琼脂(AEA)培养基和水琼脂(WA)培养基,分别作为产孢法和孢子萌发法测定辣椒炭疽病菌对嘧菌酯敏感性的适宜培养基.通过孢子萌发法测定2种病原菌45个菌株对嘧菌酯的敏感性范围在0.009~0.091μg/mL之间,平均EC₅₀为(0.047±0.040)μg/mL.其中29个C.gloeosporioides菌株和16个C.capsici菌株的平均EC₅₀值分别为(0.051±0.047)μg/mL和(0.041±0.024)μg/mL.研究发现旁路氧化酶抑制剂水杨肟酸(SHAM)对嘧菌酯抑制分生孢子萌发有协同增效作用,且嘧菌酯抑制辣椒炭疽病菌菌丝生长的能力较弱.

Baseline sensitivity of Colletotrichum gloeosporioides and C. capsici from capsium to azoxystrobin

single spore isolates causing capsium anthracnose collected from Jiangsu and Hainan provinces were identified into C. gloeosporioides and C.capsici based on the morphological characteristics. Of these isolates, 64.4% was C. gloeosporioides. Sensitivity of the C.gloeosporioides and C. capsici isolates to azo-xystrobin was determined on AEA and WA media suitable for conidium production and for spore germination test,respectively. The mean EC₅₀ value of the azoxystrobilurin inhibiting spore germination of the 45 isolates of both species was 0.047 μg/mL with a standard error of 0.040 and a range of 0.009 to 0.091 μg/mL. The mean EC₅₀ values of 29 isolates of C. gloeosporioides and 16 isolates of C. capsici isolates were (0.051±0.047) μg/mL and (0.041±0.024) μg/mL,respectively. There was coordinate synergism between azoxystrobin and salicylhydroxamic acid(SHAM) as an inhibitor of alternative oxidase against spore germination of C.gloeosporioides and C.capsici. However,azoxystrobin and SHAM inhibited mycelial growth solely and azoxystrobin was much less effective against mycelial growth.