四種蟲生真菌感染溫室內蚜蟲及其產生酵素之探討

The effect of 4 entomopathogenic fungi on aphid control in the greenhouse and enzymes synthesized by these fungi

為篩選強致病力之蟲生真菌供作蚜蟲生物防治，本試驗以九個供試菌株，分別有三個菌株為黑殭菌（Metarhizium anisopliae）代號為MA126、MA3621、HO194，三個菌株為白殭菌（Beauveria bassiana）代號為BB-1、BBU、F121，二個菌株為蠟蚧輪枝菌（Verticillium lecanii）代號為VL-578、VL615，及一個曲霉菌（Aspergillus sp.）代號為M，測試對溫室內常見之偽菜蚜（Lipaphis erysimi）、桃蚜（Myzus persicae）及棉蚜（Aphis gossypii）之致病性。九個菌株均可產生蛋白質分解酵素，其中以黑殭菌MA126及蠟蚧輪枝菌VL615菌株，於測試培養基內產生之澄清透明環寬度直徑為最大，分別為2.86、2.98 cm，同時九個菌株均檢測出lipase之酵素活性，此外利用API ZYM系統檢測出對蚜蟲有較高致病力之黑殭菌MA126、黑殭菌MA3621及蠟蚧輪枝菌VL615菌株，所產生之分解酵素如leucine aminopeptidase、valine aminopeptidase、trypsin、β-glucosidase及β-glucosaminidase的量較其它菌株為多。將蚜蟲接種孢子濃度為1×10^8 conidia/ml於28℃之室內試驗，發現黑殭菌MA126及蠟蚧輪枝菌VL615對三種蚜蟲之致死效果較其它菌株佳；溫室試驗方面，在32℃以黑殭菌MA126對桃蚜之防治效果較好，危害指數（INFI）值為1.67，其次為MA3621及白殭菌BBU，INFI值皆為2.0；在25.5℃則以蠟蚧輪枝菌VL615對桃蚜之防治效果較好，INFI值為1.0，其次為黑殭菌MA126，INFI值為1.5；因此在台灣秋冬低溫之季節，可施用蠟蚧輪枝菌VL615菌株來防治溫室內之蚜蟲，春夏較高溫之季節，可改用黑殭菌MA126菌株來噴施，藉由兩菌株於高低溫各有較強之致病性交替使用，在相對溼度高之溫室環境下，可有效控制溫室內之蚜蟲數量，同時應盡量避免和殺菌劑混合使用。

"Selected isolates of 4 entomopathogenic fungi were tested for their efficiency in controlling 3 major species of aphids, Lipaphis erysimi, Myzus persicae, and Aphis gossypii, which commonly occur in greenhouses. The fungi were MA126, MA3621, and HO194 of Metarhizium anisopliae; BB-1, BBU, and F121 of Beauveria bassiana; VL578 and VL615 of Verticillium lecanii; and M of Aspergillus sp. All 9 isolates tested produced protease and lipase as analyzed by solid differential media. But the protease activities of MA126 and VL615 were higher than those of the other isolates, because the diameter of the clearing ring from the protease reactions for MA126 and VL615 were 2.86 and 2.98 cm, respectively. The 3 strong virulent isolates of MA126, MA3621, and VL615 had higher enzymatic activities of leucine aminopeptidase, valine aminopeptidase, trypsin, β-glucosidase, and β-glucosaminidase, as analyzed by the API ZYM system. Using a conidial suspension concentration of 1 × 10^8 conidia/ml as the inoculum for the pathogenicity bioassay of aphids, results showed that the virulence of MA126 and VL615 against aphids was higher than that of other isolates at 28 °C. The virulence of MA126 against Myzus persicae was better at 32 °C, with an infestation index (INFI) value of 1.67, followed by MA3621 and BBU with INFI values of 2.0. However the virulence of VL615 against M. persicae was better at 25.5 °C, with an INFI value of 1.0, followed by MA126 with an INFI value of 1.5. Therefore VL615 can be used against greenhouse aphids in the fall and winter seasons, but during spring and summer seasons, MA126 can be used instead. Due to the high relative-humidity conditions in greenhouses, these isolates can be used effectively, but one should avoid the simultaneous use of fungicides."