海南省西瓜炭疽病菌生物学特性及药剂毒力测定

目的]研究西瓜炭疽病菌的生物学特性并初步筛选其杀菌剂。方法]从海南省大棚西瓜基地采集病样分离得到病原菌,对该病菌进行了生物学特性研究及杀菌剂室内毒力测定。结果]西瓜炭疽病菌菌丝在西瓜叶煎汁培养基上生长最好;菌丝生长和孢子萌发的最适温度分别为28和30℃;菌丝生长和孢子萌发的最适pH分别为7～9和6～8;连续黑暗条件下菌丝生长最好;孢子致死温度为55℃水浴处理5 min;以麦芽糖、阿拉伯糖和葡萄糖作为碳源的基础培养基有利于菌丝生长;以酵母浸粉、牛肉浸膏和蛋白胨作为氮源的基础培养基有利于菌丝生长。32.5%苯甲嘧菌酯SC、50%咪鲜胺锰盐WP和10%苯醚甲环唑WG对西瓜炭疽病菌菌丝生长均有很好的抑制效果,其EC50分别为0.018 0、0.060 2和0.471 5μg/ml。结论]为田间防治西瓜炭疽病提供了理论依据。

Biological Characteristics of Colletotrichum orbiculare and Toxicity Determination of Several Fungicides in Hainan Province

Objective] The paper was to study the biological characteristics of Colletotrichum orbiculare,and preliminarily screen its fungicides.Method] The pathogen was isolated from the infected leaves of watermelon collected from greenhouse in Hainan province.The biological characteristics of C.orbiculare and indoor toxicity of fungicides were studied.Result] The mycelium had the best growth on the medium with leaf extract of watermelon.The optimum temperature for mycelial growth and spore germination were 28 and 30 ℃,and the optimum pH was 7-9 and 6-8,respectively.The continuous dark condition was more suitable for mycelial growth.The lethal temperature of spore was 55 ℃ water bath for 10 min.The suitable carbon sources were maltose,L-arabinose,glucose,and the suitable nitrogen sources were yeast extract,beef extract,peptone.32.5% Benzoic azoxystrobin SC,50% Dichlorotetrakis WP and 10% Difenoconazole WG had good inhibition effects against the mycelial growth of C.orbiculare,with the EC50 values of 0.018 0,0.060 2 and 0.471 5 μg/ml,respectively.Conclusion] The research laid theoretical basis for the control of anthracnose in watermelon fields.