食真菌性線蟲Aphelenchus avenae、Aphelenchoides composticola、Paraphelenchus acontioides防治萵苣幼苗猝倒病之潛力

Using Three Fungivorous Nematodes to Control Lettuce Damping-off Disease Caused by Rhizoctonia solani (AG4)

李彥廷(Y. T. Li) ； 蔡東纂(T. T. Tsay) ； 陳珮臻(P. Chen)

《植物病理學會刊》 23卷1期 (2014/03) Pp. 43-53

https://doi.org/10.6649/PPB.201403_23(1).0004

摘要

食真菌性線蟲廣泛存在世界各地，且被認定為具有防治土壤傳播性真菌病害的潛力。本實驗由野外土壤採集得到了三種食真菌性線蟲，分別為Aphelenchus avenae、Aphelenchoides composticola和Paraphelenchus acontioides，測試結果顯示其最適生長溫度分別為Aphelenchus avenae 32~36℃、Aphelenchoides composticola 24℃和Paraphelenchus acontioides 28℃。以10種植物病原真菌、3種腐生性真菌和1種生物防治真菌來測試三屬食真菌性線蟲的取食偏好性，結果發現A. avenae 可取食最多種真菌，培養在5屬植物病原真菌Alternaria citri、Botrytis cinerea、Fusarium oxysporum、Rhizoctonia solani（AG4）、Sclerotinia sclerotiorum和商用品種Trichoderma sp.上族群可從20隻增量至400~800隻。經測試3種食真菌性線蟲皆可在R. solani（AG4）上大量繁殖，故於溫室盆缽中，測試其防治R. solani萵苣幼苗猝倒病的效果。結果顯示施用每2克土含20隻線蟲濃度的A. avenae 和P. acontioides，萵苣的植株存活率分別為88%和80%，施用每2克土1隻線蟲濃度的A. composticola，萵苣存活率仍可達為84%，三種食真菌性線蟲的處理組結果皆與單獨接種病原菌存活率4%的對照組有顯著差異。本研究結果顯示A. avenae之最適生長溫度與本土氣候條件吻合，且此屬線蟲無寄生植物的風險，有耐乾燥的脫水休眠機制，適合研發為生物防治商品。

關鍵字

萵苣猝倒病

並列摘要

Fungivorous nematodes have been reported as potential biological control agents to suppress soil-borne diseases caused by fungi pathogens. Three fungivorous nematodes; Aphelenchus avenae, Aphelenchoides composticola, and Paraphelenchus acontioides isolated from the fields in Taiwan, were tested in this study. Nematodes cultured under 6 temperature ranging from 16˚C to 36˚C were evaluated for their optimal growth temperature based on the reproduction rate. The optimal temperature for A. avenae reproduction was 32~36˚C, Aphelenchoides composticola was 24℃, and P. acontioides was 28˚C. To evaluate their food preference, ten plant pathogenic fungi, three saprophytic fungi, and one biological control fungus were used in the test. The population of A. avenae reached 400~800 nematodes when cultured on 5 phytopathogenic fungi Alternaria citri, Botrytis cinerea, Fusarium oxysporum, Rhizoctonia solani (AG4), Sclerotinia sclerotiorum and Trichoderma sp. isolated from a commercial bioagent. All three nematodes yielded the largest population when cultured on Rhizoctonia solani (AG4), therefore, their ability to control lettuce Rhizoctonia damping-off disease was evaluated under greenhouse condition. Results showed all three fungivorous nematodes could suppress the lettuce Rhizoctonia damping-off disease. Plants in the pots which were treated with 20 A. avenae per 2g soil or P. acontioides had 80% and 88% survival rates, respectively, and those treated with 250 A. composticola had 92% survival rate. These results were significantly better than the 4% survival rate in the treatment without adding fungivorous nematodes. Results suggest that A. avenae would be the best choice because of its suitability for the local temperature, without risks of plant parasitism, and could be stored through anhydrobiosis. We suggest to use in seedling for avoiding the unspecificity of food preference and having the best effect in limiting space.

並列關鍵字

fungivorous nematode ； Aphelenchoides composticola ； Aphelenchus avenae ； Paraphelenchus acontioides ； Rhizoctonia solani