六株虫生真菌的生物学特性及其对油茶象甲的致病力

Biological characteristics of six strains of entomophytic fungi and their pathogenicity against Curculio chinensis (Coleoptera:Curculionidae)

为了筛选防治油茶象甲的虫生真菌菌株,本研究测定了不同绿僵菌(Ma09、Ma25、Ma05、Mac985)和白僵菌(Bb01、Bb02)菌株的生长速度、产孢量以及孢子萌发率,采用孢悬液浸渍法测定了上述菌株对油茶象甲成虫和幼虫的致病力。结果表明,Ma09、Ma05、Bb01、Bb02菌株的菌落直径分别为63.13、62.55、61.99、61.90mm(25℃、15d),生长速度显著快于其余菌株(P<0.05);Ma25、Bb01、Ma09菌株的产孢量分别为3.04×108、2.88×108、2.85×108孢子/cm2,显著高于其余菌株(P<0.05);Bb01和Ma09菌株的孢子萌发率较高,分别达到97.80%和96.40%。不同菌株对油茶象甲成虫和幼虫致病力差异显著,其中Bb01和Ma09在1×107孢子/mL时,对油茶象甲成虫的LT50分别为4.64d和4.93d,处理后15d累计校正死亡率均达到100.00%,僵虫率分别为76.00%和78.67%;对幼虫的LT50分别为2.15d和3.48d,10d累计校正死亡率均达到100.00%,僵虫率分别为81.00%和86.31%。本研究筛选的Bb01和Ma09菌株具有生长快、产孢量大、孢子萌发率高、对油茶象甲致病力强等特性,在油茶象甲的生物防治中具有潜在的应用价值。

In order to screen fungal strains for control of Curculio chinensis , in this study, the growth rate, sporulation and spore germination rate of different Metarhizium spp.(Ma09, Ma25, Ma05 and Mac985) and Beauveria bassiana (Bb01 and Bb02) strains were determined. The pathogenicity of the above strains to adults and larvae of C.chinensis was determined by impregnation metnod. The results showed that the colony diameters of Ma09, Ma05, Bb01 and Bb02 strains on 15 th days were 63.13 mm, 62.55 mm, 61.99 mm, and 61.90 mm at 25℃, respectively,which were significantly higher than the other strains ( P <0.05). The production of spores of Ma25, Bb01, and Ma09 were 3.04×10^8 , 2.88×10^8 , 2.85×10 8 spores/cm^2 , significantly higher than the rest of strains ( P <0.05). The spore germination rates of Bb01 and Ma09 were 97.80% and 96.40%, respectively, which were also significantly higher than other strains. The pathogenicity of different strains showed significant differences against adults and larvae of C.chinensis . For C.chinensis adults treated with Bb01 and Ma09 at concentration of 1×10^7 spores/mL, the LT 50 were 4.64 d and 4.93 d, respectively, the accumulative corrected mortality of both reached 100.00% on the 15th day, the infection rates were 76.00% and 78.67%, respectively. For the larvae treated with Bb01 and Ma09 at concentration of 1×10 7 spores/mL, the LT 50 were 2.15 d and 3.48 d, respectively, the accumulative corrected mortality of both reached 100.00% on the 10th day, and the infection rates were 81.00% and 86.31%, respectively. The Bb01 and Ma09 strains screened in this study have the characteristics of high growth rate, large spore production, high spore germination rate and strong pathogenicity to C.chinensis , indicating their potential application value in biological control of C.chinensis.