番石榴枯萎病菌生物学特性及生防菌和防治药剂的筛选

Biological characteristics of the pathogen of guava wilt and screening of biocontrol bacteria and control agents

【目的】明确番石榴枯萎病菌的生物学特性,并进行生防菌和防治药剂筛选,为番石榴枯萎病的发生规律及高效防控提供理论依据。【方法】在不同碳源、温度、pH、NaCl浓度等培养条件下,测定番石榴枯萎病菌GS-1的生物学特性,采用平板对峙法筛选GS-1的生防菌,并利用菌丝生长速率法测定6种常用杀菌剂对病原菌的抑制效果。【结果】番石榴枯萎病菌GS-1菌丝生长的最佳碳源为果糖,产孢最佳碳源为果糖和甘露醇;菌丝最适生长温度为30℃,最适生长pH为6;温度为28~46℃时均有大量孢子萌发,52℃时孢子完全失去活性;番石榴枯萎病菌GS-1菌丝具有一定的耐盐性。生防菌解淀粉芽孢杆菌B2对病原菌GS-1生长的抑制效果最佳。番石榴枯萎病菌GS-1菌丝对咪鲜胺的敏感性最高,0.0004μg/mL咪鲜胺条件下不生长;其次为吡唑醚菌酯和甲霜灵,EC50分别为0.4912和0.8805μg/mL。【结论】番石榴枯萎病菌适生范围较广,温度较高、中性偏弱酸的环境条件利于其快速生长繁殖,咪鲜胺、吡唑醚菌酯和甲霜灵可作为防治番石榴枯萎病的药剂。

【Objective】The biological characteristics of Nalanthamala psidii,a causal agent of guava wilt,were studied,and biocontrol bacteria and control agents were screened in order to investigate the occurrence rule and control strategies of guava wilt.【Method】The biological characteristics of N.psidii GS-1 were detected under cultivation conditions with different carbon source,temperature,pH and NaCl concentration.The biocontrol bacteria for GS-1 was screened using plate confrontation method.The mycelial growth rate method was used to determine the inhibitory effects of six types of commonly fungicides on the pathogen.【Result】The optimal carbon source for mycelial growth of GS-1 was fructose,and the optimal carbon sources for conidia germination were fructose and mannitol.The most suitable temperature and pH for mycelial growth were 30℃and 6 respectively.Plenty of conidia could germinate at the temperature of 28 to 46℃.The lethal temperature of conidia was 52℃.The GS-1 mycelia had certain degree of salinity tolerance.Bacillus amyloliquefaciens isolate B2 had the highest inhibitory effect on GS-1 growth.The GS-1 mycelia was the most susceptible to prochloraz and it did not grow when the content of prochloraz was 0.0004μg/mL,followed by pyraclostrobin and metalaxyl with EC50 of 0.4912 and 0.8805μg/mL,respectively.【Conclusion】The pathogen of guava wilt has a wide range of suitable habitat,and environmental conditions of higher temperature and neutral to weak acidity are conducive to its rapid growth and reproduction.Prochloraz,pyraclostrobin and metalaxyl can be used to control guava wilt.