黄绿绿僵菌与反式茴香脑的相容性及其对菜青虫的联合毒力

Compatibility of Metiarium flavoride with Trans-Anethole and Their Cotoxicity to Pieris rapae

为了明确植物次生代谢产物反式茴香脑与高毒力昆虫病原真菌黄绿绿僵菌Mf82菌株的相容性以及其对菜青虫的联合毒力,本文在室内评价了半致死浓度(LC_(50))反式茴香脑与黄绿绿僵菌Mf82不同浓度孢子悬浮液以不同体积比混合后对菌株生长的影响,并测定了菌药联合使用对2龄菜青虫的毒杀效果。结果表明,黄绿绿僵菌与反式茴香脑对菜青虫均有良好的毒杀活性;反式茴香脑LC_(50)剂量与黄绿绿僵菌Mf82混合对菌株的菌落生长有一定促进作用,两者以体积比5:5、4:6和3:7处理后明显促进菌丝生长,且随着反式茴香脑在混剂中所占比例增大促进作用增强,孢子萌发率也比两者以2:8和1:9混合后的孢子萌发率高;混剂对菜青虫的致死率随二者混合比例的不同而变化,其中反式茴香脑LC_(50)分别与孢子悬浮液(1.5×10^(4)~1.5×10^(8)孢子/mL)以体积比5:5、4:6和3:7混合处理试虫的死亡率高于两者以2:8和1:9混合处理的死亡率,共毒系数分别为287、108和83,表明具增效与相加作用;以体积比5:5、4:6和3:7混合处理的致死中时(LT_(50))也比单用黄绿绿僵菌的短。因此,在防治菜青虫时应选择相容性好、共毒系数高的混合比例,即5:5、4:6或3:7。黄绿绿僵菌和反式茴香脑联合应用对菜青虫的高毒力表明其具有开发成生物制剂用于对害虫进行高效安全绿色防控的潜力。

The compatibility of plant secondary metabolite trans-anethole with a highly virulent entomopathogenic fungi Metarhizium flavoride Mf82 were evaluated using mixtures of LC_(50) of trans-anethole and different concentrations of conidial suspensions of M.flavoride Mf82 at different ratios in terms of the colony growth of M.flavoride and their co-toxicity against the 2^(nd) instar larvae of Pieris rapae in the laboratory.Results indicated that each of the two showed good insecticidal activities against the 2^(nd) instar larvae of P.rapae.The mixture of the two promoted the mycelia growth of M.flavoride to some extent,the effect was significant when the mixture ratios were at 5:5,4:6 and 3:7 and was even significant as the proportion of trans-anethole in the mixture increased.The conidia germination rate was also higher than in the mixtures mixed at 2:8 and 1:9.The mortalities of the 2^(nd) instar larvae of P.rapae treated with the mixtures varied with the mixing ratios,the mixtures of the two at mixing ratios of 5:5,4:6 and 3:7 resulted in higher mortalities than that obtained with the mixtures mixed at 2:8 and 1:9,with co-toxicity coefficients of 287,10^(8) and 83,respectively,indicating synergistic and additive effects.The LT_(50) values of the mixtures mixed at 5:5,4:6 and 3:7 were smaller than that of M.flavoride alone.In the control practice of P.rapae,it is recommended to use the mixing ratios with good compatibility and high co-toxicity coefficient of the two agents,that is,trans-anethole(LC_(50))and M.flavoride Mf82 mixed at 5:5,4:6 and 3:7.The high cotoxicity of the combination of M.flavoride with trans-anethole indicates that the mixture can be a potential alternative to the chemicals as an effective component of IPM program against P.rapae.