玫烟色棒束孢耐热菌株的筛选及对麦长管蚜的致病力测定

Screening of thermo-tolerable Isaria fumosorosea strains and virulence evaluation to Sitobion avenae

采用48℃恒温水浴热胁迫法对玫烟色棒束孢7个菌株进行了耐热性测定。结果表明,热胁迫45 min后,不同菌株的残存活孢率差异显著,其中IF-502、IF-904和IF-9606菌株耐热性较强,残存活孢率均达50%以上;IF-7606菌株耐热性最差,残存活孢率仅为28.70%;IF-14、IF-511和IF-609菌株耐热性居中,残存活孢率34.72%～36.00%。对耐热性强的IF-502、IF-904和IF-9606三个菌株对麦长管蚜若蚜的致病力测定表明, IF-904菌株在1×10~7孢子/mL时对麦长管蚜的致病力最高,校正死亡率达88.20%,致死中时最短,为2.67 d。

Thermotolerance of seven Isaria fumosorosea strains were determined by exposing thermal stress at 48℃ for 45 min. The results showed that residue viabilities differed significantly among seven strains tested, three strains including IF-502, IF-904, IF-9606 were high thermotolerance due to their residue viabilities more than 50%, but one strain (IF-7606) was weak in thermotolerance due to its residue viabilities of 28.70%. The residue viabilities of the rest strains fell in a range of 34.72%-36.00% and their thermo-tolerance were thus intermediate. In addition, virulence evaluation of high thermo-tolerant strains including IF-502, IF-904 and IF-9606 showed that the IF-904 strain was the highest virulent strain to Sitobion avenae with the corrected mortality of 88.20% and the shortest LT 50 was 2.67 days.