立枯絲核菌係造成百合根腐病的主因之一，當將纏據於無菌百合組織上的本菌，置於壤土的不同生態條件下，即 -1.37、-0.51、-0.23 及 -0.12 bar 之水份潛勢，20、25、30 及 35℃ 的土壤溫度，及 5、10、20 及 30 公分的土壤深度中；其中水份潛勢及時間顯著地影響立枯絲核菌之存活，水份潛勢愈小，時間愈久，病原的存活率愈少。當壤土中的水份潛勢為 -1.37 bar 或溫度為 35℃時，在其中添加拮抗菌可有效地降低病原族群，尤其是添加量為1010 cfu/ g 土壤時，效果更形明顯。B. megaterium 18 或 S26 並不會影響或抑制百合在土壤中之生長，當壤土的水份潛勢為 -0.51 bar時，以 B. megaterium 18 或 S26 處理百合，可顯著地 (p=0.05) 抑制立枯絲菌對百合的侵害。
Rhizoctonia solani was one of the most important pathogens to cause root rot of lilies. Rhizoctonia solani- colonized lily tissues were used to test the survivability of R. solani under various soil conditions. Loam soil was used in this study. Four different water potentials (i.e. –1.37, -0.51, -0.23, and –0.12 bar), temperatures (20, 25, 30 and 35°C), and soil depths (5, 10,20 and 30 cm) were the variables. Among them, water potential and time were the critical factors to influence the survivability of R. solani. Low soil water potential (<-0.51 bar) and long time periods (> 50 days) decreased the survival rate of the studied pathogen. When soil amended with antagonist Bacillus megaterium 18 or S26 for 24-40 days, the activities of soil l1icrobes increased and the population of R. solani decreased. When the water potential and temperature of m soil were maintain at –1.37 bar and 35°C, the soil amended with B. megaterium #18 or 526 (1010 cfu/ g soil, especially) decreased the population of R. solani significantly. Bacillus megaterium did not affect the growth of lilies adversely. When soil water potential was kept at –1.37 or –0.51 bar, the presence of B. megaterium 18 or S26 protected effectively lilies from the infection with R. solani.
