感染瓜实蝇的曲霉菌及其生物学特性

从海南自然发病死亡的瓜实蝇上分离获得2株高毒力的真菌BC-D1和BC-212,经形态学和ITS序列鉴定结果表明, BC-D1为黄曲霉Aspergillus flavus,BC-212为溜曲霉Aspergillus tamarii。室内毒力测定结果发现：菌株BC-D1和BC-212对瓜实蝇成虫均有很高毒力,而对卵、幼虫及蛹的毒力较低。接种8d后成虫的平均死亡率分别为73.5%和85.1%,卵、幼虫及蛹的死亡率均低于50%。两株菌对黄粉虫、斜纹夜蛾及蚜虫的致病率均很低。生物学特性测定,两菌株具有生长速度快、产孢量大的特性,最适合生长的温度范围为30-35℃;在不同营养成分的培养基上,菌株生长速率、产孢量及菌落颜色存在较大差异。

Aspergillus spp.isolated from Bactrocera cucurbitae in Hainan and their biological characteristics

Two Aspergillus strains (BC-D1 and BC-212) were isolated from dead and mycosed adults of the melon fly Bactrocera cucurbitae in Hainan. The strain BC-D1 was identified as Aspergillus flavus and the strain BC-212 was Aspergillus tamarii based on their morphological characters and the rDNA-ITS fragment sequences. The virulence of BC-D1 and BC-212 against B. cucurbitae was tested in laboratory. The results indicated that two Aspergillus species had higher virulence against the adults of B. cucurbitae than against insect larvae, pupae and egg. The mortalities of adults in 8d after inoculation with BC-D1 and BC-212 were 73.5% and 85.1%, respectively. However, mortalities of the larvae, pupae and egg were less than 50%. Both species caused very low mortalities against the larvae of Tenebrio molitor, Spodoptera litura, and Lipaphis erysimi. They were characteristed by rapid growth and high sporulation. The optimum growth temperature were 30-35°C. With the difference of nutritional composition in medium, the growth rate, sporulation and morphology features were comparatively different from each other.