金龟子绿僵菌对红棕象甲的室内致病力测定

Detection of Pathoqenicity of Meatarhiziums against Rhynchophorus ferrugineus in Laboratory

在室内用喷雾法测定13株绿僵菌对红棕象甲的致病力。结果表明,菌株致病力强弱与菌株种类有密切关系,菌株的浓度与累计死亡率成线性关系。菌株对红棕象甲的致病力由强到弱的顺序为:Red2>Red3>Gre1>Yx7>Yx4>Gre3>Red1>Yx1>Gre2>Yx6>Gre4>Gre5>Yx3。接种Red2菌株在孢子浓度为1.0×108个/mL水悬浮剂情况下,对4龄红棕象甲幼虫的LT50为5.23 d。用不同浓度的Red2菌株的孢子油悬浮剂涂抹法接种4龄幼虫,发现其LC50为7.32×106个/mL。另外,经试验观察发现,油悬浮剂比水悬浮剂对红棕象甲幼虫更有效,在Red2菌株浓度都为1.0×108个/mL情况下,油剂LT50仅为3.81 d。

The pathogenicity of thirteen Metarhiziums sp. isolates against Rhynchophorus ferrugineus was bioassayed in laboratory by spraying. Close relationship was found between the virulence and the isolates. Linear relationship was found between the concentration and the mortalities. The pathogenicity of the isolates against R. ferrugineus is in the order of Red2〉Red3〉Grel〉Yx7〉Yx4〉Gre3〉Redl〉Yxl〉Gre2〉Yx6〉Gre4〉Gre5〉Yx3. The LD50 of the fourth instar larvae inoculated with isolate Red2 at 1.0×10^8 spores/mL aqueous suspension was 5.23 d. When inoculated with different levels of oil miscible flowable concentrate （OF） of Red2, the larvae had a LCso of 7.23×10^6 spores/mL. Furthermore, the OF was more effective than aqueous suspension for the larvae, the LTso of OF inoculated with Red2 at 1.0×10^8spores/mL is only 3.81 d.