本研究以臺灣櫸病株所分離之褐根腐病菌菌株 (EXFOPH21、EXFOPH22) 進行臺灣櫸兩年生袋苗之致病性研究，分別將兩褐根腐病菌株培養於已滅菌之燕麥粒培養基中作為接種源，接種於兩年生臺灣櫸袋苗的根部，皆可使臺灣櫸致病並產生相同病徵，自接種試驗苗木的罹病根部均可分離出相同病原菌；而接種期間對照組植株生長良好。本研究亦以臺灣肖楠及臺灣紅檜之木材精油，對褐根腐病菌菌絲在馬鈴薯瓊脂培養基平板上之生長抑制能力評估，當有效濃度為100 ppm時，臺灣紅檜、臺灣肖楠兩種精油可完全抑制褐根腐病菌之菌絲生長。

Brown root rot pathogens (EXFOPH21, EXFOPH22) were isolated from infected Zelkova serrata. Pathogens were first grown in sterile oat grains and subsequently inoculated onto the roots of healthy Z. serrata seedlings. These seedlings were infected after the inoculation. The control seedlings still grew well. Moreover, the roots of infected seedlings could isolate the same fungi. Inhibitions of volatile oils to mycelia growth of brown root rot pathogens were estimated by PDA (potato dextrose agar). The result showed that the volatile oils extracted from Chamaecyparis formosensis and Calocedrus macrolepis Kurz var. formosana could significantly inhibit the mycelia growth of brown root rot fungi at the concentration of 100 ppm.