Abstract:

【Objective】 To clarify the biological characteristics of Xanthoceras sorbifolia root rot pathogen, melon and Pythium aphanidermature, and screen fungicides with obvious bacteriostatic effect, so as to provide alternative fungicides for field fungicide screening of Xanthoceras sorbifolia root rot.【Methods】 In the experiment, the mycelial growth rate method was used to determine the growth rate of pathogens under different carbon sources, temperatures and pH values, so as to clarify the main biological characteristics of pathogens. Through the indoor drug virulence determination experiment of pathogenic bacteria, the prevention and control drugs were screened out. 【Results】 The biological characteristics of pathogens showed that the pathogens could grow in 8 different carbon source media, but the growth on PDA and CMA was better than the other 7 cultures. The pathogens grew best on PDA, followed by CMA, PCA, OA, PSA, carrot, WA, MA; the pathogen could grow at 15-40℃, and the optimum temperature was (35±1)℃; the pathogen could grow at pH 4-11, among which the optimal growth was when the pH value was 8.0; 30% benzalkonium · hymexazol was the most virulent, with an EC₅₀ value of 1.259,9 mg/L, followed by 50% Pythium · Thiram with an EC₅₀ value of 8.156 4 mg/L, while 2×10⁹ CFU/g Bacillus subtilis was the least virulent, with an EC₅₀ value of 4,107.327 mg/L.【Conclusion】 Among the 8 different carbon source media tested, the optimum medium is PDA, the optimum growth temperature is about 35℃ and the optimum pH value 8. All the 12 fungicides tested have certain inhibitory effects on the mycelial growth of pathogenic bacteria, Among which, metalaxyl oxamyl has the best antibacterial effect, followed by Pythium thiram and mancozeb. The three fungicides can be used as alternative fungicides for the field control of Xanthoceras sorbifolia root rot.

Key words: Xanthoceras sorbifolia; root rot; biological characteristics; virulence determination

摘要：

【目的】研究文冠果根腐病菌瓜果腐霉(Pythium aphanidermature)的生物学特性,筛选抑菌效果明显的杀菌剂,为文冠果根腐病田间药剂筛选提供备选药剂。【方法】采用菌丝生长速率法分别测定病原菌在不同碳源、温度和pH值条件下的生长速率,分析病原菌主要生物学特性。运用病原菌的室内药剂毒力测定试验,筛选高效抑菌药剂。【结果】病原菌在8种不同碳源培养基上均可生长,其中在PDA上生长速率明显优于其它7种培养基,病原菌在PDA上生长最好,其次为CMA、PCA、OA、PSA、胡萝卜、WA和MA;病原菌在15~40℃均可生长,且最适温度在(35±1)℃;病原菌在pH值为4~11均可生长,其中pH值为8.0时生长最优;30%甲霜·噁霉灵毒力最大,EC₅₀值为1.259 9 mg/L,其次为50%腐霉·福美双,EC₅₀值为8.156 4 mg/L,而2×10⁹ CFU/g 枯草芽孢杆菌毒力最小,EC₅₀值为4 107.327 mg/L。【结论】在8种不同碳源培养基中,最适培养基为PDA,最适生长温度为35℃左右,最适pH值为8。供试12种药剂对病原菌菌丝生长均具有一定的抑制效果,其中甲霜·噁霉灵的抑菌效果最好,其次为腐霉·福美双和代森锰锌,3种药剂可作为文冠果根腐病田间防治药剂的备选药剂。

关键词: 文冠果, 根腐病, 生物学特性, 毒力测定