从桔蚜上分离的一种致病镰刀菌

A SPECIES OF ENTOMOGENOUS FUNGUS FUSARIUM LATERITIUM ISOLATED FROM CITRUS APHID

从福建省南平市桔蚜虫尸上分离的一株镰刀菌 ,病原鉴定为镰刀菌属 (FusariumLinkexFn)的砖红镰孢 (FusariumlateritiumNees .)。病原菌在PDA培养基上生长旺盛 ,10～ 3 5℃均可生长 ,生长适宜温度为 2 0～2 6℃ ,2 5℃下培养 3d后可产孢。分生孢子萌发最适宜温度为 2 0～ 2 5℃ ,最适宜的相对湿度为 96%～ 10 0 %。对桔蚜若虫的毒力测定表明 ,砖红镰孢对桔蚜具有较强的致病力 ,其LC50 为 2 71× 10 7个孢子·L- 1 ,LT50 为2 2 1～ 6 3 4d(在 1 0× 10 1 1 ～ 1 0× 10 7个孢子·L- 1 浓度下 )。用砖红镰孢菌液田间防治桔蚜 ,死亡率达91 80 %。

A species of entomogenous fungus was isolated from dead insect bodies of citrus aphid in Nanping city, Fujian Province. The species was identified as Fusarium lateritium Nees. of the genus Fusarium. The causal organism grew vigorously on PDA medium. Mycelia of the fungus grew at temperature range 10～35℃, and with an optimum at 20～26℃. The conidia was produced after incubation of 3 days at 25℃.The optimum temperature for conidial germination was between 20～25℃. The high relative humidity (96%～100%) was necessary for the germination of conidia. Bioassay results indicated that the fungus showed higher virulent to the larvae of citrus aphid. The LC 50 was 2 71×10 7 spores·L -1 , and the LT 50 2 21～6 34 days for the concentration of 1 0×10 11 ～1 0×10 7 spores·L -1 .The spore suspension of F.lateritium was applied to control test in the field against citrus aphid, and the mortality was 91 80%.