黄曲霉对桔小实蝇蛹致病性的初步测定

Pathogenicity of Aspergillus flavus against Bactrocera dorsalis pupae

为筛选防治桔小实蝇的微生物杀虫剂,本研究对桔小实蝇死亡成虫虫体上的一株真菌,进行单孢分离和培养,经鉴定该菌株为黄曲霉(Aspergillus flavus)。利用浸泡法及蘸粉法分别测定了黄曲霉对桔小实蝇蛹的致病性,研究结果表明:浸泡法中孢悬液处理桔小实蝇蛹,蛹的感染率随孢子浓度增加而增大,蛹的羽化率随孢子浓度的增加而减小。蘸粉法对桔小实蝇蛹的感染率可达100%,显著高于高浓度孢悬液(1.0×10^(8)个/mL)浸泡法对蛹的感染率,而在成虫羽化率方面没有显著差异。在感染速率方面,添加0.1%吐温-80在前24 h会减缓侵染速度,各处理均在48 h之前侵染速率达到最快,在72 h侵染达到最大值。研究结果可为桔小实蝇生防菌的有效筛选提供依据。

In order to screen microbial insecticides for the control of Bactrocera dorsalis,a strain of fungus found on the naturally died body of B.dorsalis adult in our laboratory was isolated and cultured.The isolate was identified as Aspergillus flavus.The pupae of B.dorsalis were inoculated by methods of soaking and dipping spores powder.The results showed that the infection rate of pupae increased with the increase of spore concentration,while the eclosion rate of pupae decreased with the increase of spore concentration by soaking method.The infection rate of spore powder dipping method to the pupa of B dorsalis could reach 100%,which was significantly higher than that of high concentration spore suspensions(1.0×10^(8)spore/mL)by soaking method,but there is no significant difference in the eclosion rate of adults.On infection rate,the addition of 0.1%Tween-80 would slow down the infection rate in the first24 hours,and then the infection rate of spore suspension of each concentration increased fastest before 48hours,and reached the maximum at 72 hours.The results could provide a basis for the effective screening of biocontrol microorganisms to B.dorsalis.