椒草白绢病菌生物学特性及其防治药剂的初步研究

目的]了解椒草白绢病菌的生物学特性和筛选有效的杀菌剂。方法]采集具有典型症状的病害标本,根据柯赫氏法则分离病原物,并分别测定不同的温度、湿度、pH值以及碳氮源和光照对该病菌菌丝生长和菌核萌发的影响,同时,测试5种杀菌剂在3种不同浓度下对病原菌的抑菌作用。结果]结果表明,白绢病菌菌丝生长最适温度为30℃,最适pH值为6,最适合的碳源、氮源为蔗糖和硝酸钾;黑暗条件有利于菌丝的生长,而光照条件有利于菌核的产生。当pH值为4～6时,培养2 d后菌核的萌发率达100%;菌核的萌发需要足够的水分。供试药剂中以3%水剂井冈霉素和50%使百功防效最为明显,分别在400和200μg/m l时的防效高达98%以上。结论]温暖潮湿、偏酸性的环境适合白绢病菌的生长和繁殖,井冈霉素可作为防治白绢病的有效药剂用于田间该病害的控制。

Study on Biological Characteristics and Chemical Control of Sclerotium roffsii Sacc. Caused Peperomia tetraphylla Southern Blight

Objective]The research aimed to evaluate biological characteristics and screen effective fungicides of Sclerotium roffsii Sacc.caused by Peperomia tetraphylla southern blight.Methods] The disease samples showing typical symptom were collected and pathogen was isolated based on Koch's rule.The biological characteristics of the pathogen were conducted,and 5 fungicides were selected and used for controlling the disease.Results]The results showed that the optimum carban and nitrogen resource were sucrose and lopassium niruate.The growth rates of mycelia were fastest at the temperature of 30 ℃ and pH value 6.Darkness was benefitial to hyphal growth,but light was benefitial to sclerotial formation.Sclerotia cultured in pH value 4-6 could germinate at 100% after 2 days.It only germinated in 100 relative humidity and added water.The toxicity test in vitro showed that the inhibition rate of 3% Validamycin to Sclerotium roffsii was above 98% at the concentration of 400 μg/ml.Conclusion]In the warm,humid and acidic circumstance where is benefitial to hyphal growth and reproduction of Sclerotium roffsii Sacc..Validamycin can be used as an effective fungicide.