六种杀菌剂对黄瓜霜霉病菌不同发育阶段的影响

The Effect of Six Fungicides on Different Developmental Stages in the Life Cycle of Pseudoperonospora cubensis

用Calco fluor荧光染色和显微观察的方法研究了6种常用杀菌剂对黄瓜霜霉病菌Pseudoperonospora cubensis不同发育阶段的影响。结果表明:烯酰吗啉和氟吗啉对黄瓜霜霉病菌孢子萌发、芽管伸长、附着胞形成、菌丝扩展、孢囊梗和孢子囊的形成具有明显的抑制作用,其EC50值分别在0.07～5.98μg/mL和0.10～3.50μg/mL之间,而对游动孢子释放、游动孢子游动和休止孢形成没有抑制作用;霜脲氰对休止孢萌发和芽管伸长的EC50值分别为1.10和0.002μg/mL,对其他阶段无明显的抑制效果;腈嘧菌酯对休止孢萌发、菌丝扩展和孢囊梗产生无影响,对游动孢子释放、芽管伸长和附着胞形成的EC50值分别为0.018、0.008和0.010μg/mL;代森锰锌对游动孢子释放、休止孢萌发和芽管伸长的EC50值分别为2.40、2.88和1.53μg/mL;甲霜灵对该菌的整个发育期均没有影响,这可能是因为供试菌株对甲霜灵已经产生了抗药性。

The effect of six fungicides on different stages in the life cycle of P.cubensis was studied by calcofluor fluorescent technique. The results showed that dimethomorph and flumorph had no effect on zoospore discharge, zoospore move and cystospore formation but prevented (cystospore)( germination, )germ tube elongation, appressorium formation, mycelial growth in vivo, sporrangiophore emerge from stomata and sporangial formation. The EC_(50) of these two fungicides to different stages of P.(cubensis) were ranged from 0.07～5.98 μg/ mL and 0.10～3.50 μg/ mL, (respectively.) The EC_(50) of (cymoxanil) to cystospore germination and the growth of germ tube were (1.10) and (0.002 μg/ mL,) but it had no effect on other (stages). Azoxystrobin can prevent all stages of P.cubensis but cystospore( germination )and sporangiophore (production). Its EC_(50) were 0.018, 0.008 and 0.010 μg/ mL to zoospore discharge, germ tube elongation and appressorium formation, (respectively.) The EC_(50) of mancozeb to zoospore discharge, cystospore (germination) and germ tube elongation were 2.40, 2.88 and 1.53 μg/ mL, it has small effect on P.cubensis mycelium in leaf tissue, appressorium formation and sporangiophore( production). metalaxyl had no effect on any stages of P.cubensis.