評估兩種精油抑制病原真菌生長及防治草莓灰黴病之效果

Evaluation of two essential oils on mycelial inhibition of fungal pathogens and control of gray mold in strawberry in Taiwan

"評估柚子與檸檬桉精油對八種植物病原真菌菌絲生長的抑制效果，得知未稀釋之柚子精油透過燻蒸方式，可分別抑制草莓灰黴病菌GBS3-93與GBS1-104菌株菌絲生長達92.7%與100.0%，然對綠黴病菌Cmep1-3菌株則有促進生長效果；而檸檬桉精油在稀釋低於10倍時，可抑制八種植物病原真菌菌絲生長達96.6%-100.0%。在PDA培養基添加精油試驗中，顯示稀釋100倍柚子精油對小白菜炭疽病菌PA01菌株與草莓灰黴病菌GBS1-104和GBS3-93菌株之生長抑制率較佳，分別有89.8%、81.1%及73.4%，然對綠黴病菌Cmep1-3菌株有促進生長現象；而添加檸檬桉精油結果得知，稀釋1,000倍檸檬桉精油時，可抑制多數供試植物病原菌株生長。評估柚子與檸檬桉精油對七種植物病原真菌孢子發芽的抑制效果，結果顯示稀釋50倍以下的柚子精油，對其中5種病原真菌抑制效果達92.6%以上，然對綠黴病菌Cmep1-3菌株則具有促進孢子發芽效果（>65.4%）；而檸檬桉精油稀釋至500倍時，仍對所有供試病原菌菌株孢子發芽具有80.1%以上的抑制效果。評估兩種精油防治草莓灰黴病之效果，結果得知於接種病原後1小時再施用兩種精油之防治效果表現較佳。以氣相層析質譜聯用技術分析上述兩種精油主要成份，證實柚子精油中的主要成分為檸檬烯，約含96.27%；而檸檬桉精油之主要成分為香茅醛與香茅醇，含量分別約為43.69%與17.06%。"

"Two essential oils extracted from pomelo (Citrus maxima) and lemon eucalyptus (Eucalyptus citriodora) were evaluated their inhibitory effects on mycelial growth of 8 plant fungal pathogens. The fumigation test showed that the pomelo essential oils (PEO) without dilution had best inhibitory ability to mycelial growth of Botrytis cinerea by 92.7% for isolate GBS3-93 and by 100% for isolate GBS1-104, whereas mycelial growth of Penicillium digitatum isolate Cmep1-3 was induced. The lemon eucalyptus essential oil (LEEO) with 10-fold dilution could inhibit mycelial growth of all fungal pathogens by 96.6~100.0%. In PDA medium added with essential oil test, 100-fold dilution PEO showed the best growth inhibition by 81.1% for isolate GBS3-93, by 89.8% for isolate GBS1-104 and by 73.4% for Colletotrichum higginsianum isolate PA01, respectively, while mycelial growth of Cmep1-3 was induced. All of fungal pathogens were inhibited by 1,000-fold dilution LEEO. In spore germination test, the 50-fold dilution PEO could inhibit 5 fungal pathogens more than 92.6% and induce spore germination of Cmep1-3 more than 65.4%; meanwhile, LEEO could inhibit the germination more than 80.1% under 500-fold dilution. Spraying PEO and LEEO at 1 hr after B. cinereal pathogen inoculation in a greenhouse showed significantly control efficacy compared with pathogen inoculation only. The GC-MS analyses demonstrated that major compounds were limonene (96.27%) for PEO and citronellal (43.139%) and citronellol (17.06%) for LEEO, respectively."