利用拮抗菌－蛭石夾層法防治立枯絲核菌引起之幼苗猝倒病

Appication of Antagonisitc Microorganisms in Double-layers of Vermiculite to Control of Seedling Damping-off Caused by Rhizoctonia Solani

莊再揚( T. Y Chuang) ； 黃莉娟( L. J Hwang) ； 安寶貞( P. J Ann)

《植物病理學會刊》 10卷1期 (2001/03) Pp. 1-10

https://doi.org/10.6649/PPB.200103_10(1).0001

摘要

利用夾層法（三明治法）將種子夾於拮抗菌－蛭石混合物中間以防治立枯絲核菌（Rhizoctonia solani AG-4）引起之幼苗猝倒病。這種夾層法設計如下：將拮抗微生物與蛭石混合，使微生物濃度在每毫升106以上，然後在室溫下(25-28°C)陰乾。將厚度一公分厚的拮抗菌－蛭石舖於栽培介質（含病菌）的上面為底層，然後將種子於其上，再將一層一公分厚的拮抗菌－蛭石覆蓋於種子之上。利用這種方法，Bacillus subtilis （菌株Tp-Tu311）與酵母菌Sporobolomyces sp.（菌株Y11-2）均可顯著的降低14種供試作物因立枯絲核菌所引起的幼苗猝倒病。供試的14種作物包括萵苣、蘿蔔、結球白菜、東京白菜、甘藍、花椰菜、胡蘿蔔、菠菜、番茄、夾碗豆、菜豆、綠豆、大豆、飼料玉米等。其中以B. subtilis Tp-Tu311的效果較Sporobolomyces sp. Y11-2為好。此外，即使衹用無菌蛭石，亦能阻隔部份病原菌，減少發病情形。拮抗微生物的防病效果隨著病原菌密度增加而減少，在接種源濃度1%蛭石中，Tp-Tu311的防病效果較Y11-2為佳。而一般拮抗菌濃度為106/ml以上時，就能顯著降低發病。將拮抗菌－蛭石混合物陰乾後儲存於室溫及4°C下經12週，其防治蘿蔔幼苗猝倒病之效果與剛配製時相同，無顯著差異。拮抗菌－蛭石混合物陰乾後在室溫貯存12個月，仍具良好的防病效果。拮抗菌－蛭石混合陰乾後，添加馬鈴薯葡萄糖酵母菌液(PDYB)、黑糖、糖密液等，均無法顯著提升其防病效果。將豌豆、胡瓜、蘿蔔與番茄播種在抗拮菌－蛭石中，種子萌芽一週後，再移植到不同濃度的病原菌－蛭石中，並無防病效果。模擬微區試驗，拮抗微生物雖然能增加蘿蔔幼苗之存活率，但防病效果不如直接播種者為佳，其中以菌株Tp-Tu311的治效果最好。

關鍵字

立枯絲核菌 ； 苗立枯病 ； 生物防治 ； 夾層法

並列摘要

A sandwich design consisting of laying seeds in between double layers of antagonist-vermiculite mix for control of seedling damping-off caused by Rhizoctonia solani was developed. Antagonistic microorganisms were added to vermiculite at the concentration of about 106-8 cfu/m1, and the mixtures were air-dried at room temperature for 24 hr. One centimeter thick of antagonistic microorganisms-vermiculite mixture was put on the top of the cultural medium with R. solani. Seeds were then placed on the mixture and covered with another layer of antagonist-vermiculite mix. When isolates of Tp-Tu311 & Tn-Y21 of Bacillus subtilis or Yll-l & Y11-2 of Sporobolomyces sp. were applied to cultural media as described above, radish seedling damping-off caused by R. so/ani AG-4 significantly decreased. Among the four tested antagonists, isolate Tp-Tu311 of B. subtilis was most effective. As long as the concentration of the antagonistic bacteria in the vermiculite mixture was higher than 106 cfu/ml, the Tp- Tu311 was effective in reducing the Rhizoctonia damping-off. The inhibition activity of the four isolates in the airy-dried antagonist -vermiculite mix persisted for at least 12 months under room temperatures. Using double layers method, isolates Tp- Tu311 of B. subtilis and isolate Y 11-2 of Sporobolomyces sp. significantly reduced the seedling damping-off of 14 species of crops. The 14 tested crops were cabbage, Chinese cabbage, carrot, cauliflower, Tokuyo pai-tsai, radish, tomato, lettuce, spinach, mung bean, garden pea, soybean, common bean, and corn. Amendment of Potato-dextrose-yeast broth (PDYB), crude sugar, or mo1asses to stored antagonist-vermiculite mix was not effective in increasing its suppressive activity.

並列關鍵字

double-layers method ； biological control ； Rhizoctonia solani ； Bacillus subtilis ； Sporobolomyces sp.