球孢白僵菌和中华甲虫蒲螨对冷杉梢斑螟杀虫作用及其相关酶活性影响

Toxicity and Killing Effect of Beauveria bassiana and Pyemotes zhonghuajia on Dioryctria abietella and Related Enzyme Activities

为研究球孢白僵菌(Beauveria bassiana)和中华甲虫蒲螨(Pyemotes zhonghuajia)对冷杉梢斑螟(Dioryctria abietella)的毒杀作用及冷杉梢斑螟的解毒、保护机制,采用浸虫法和室内接种蒲螨的方法,测定了CFCC81428、CFCC83116这两株菌的亚致死浓度(LC_(25))、半数致死浓度(LC_(50))和中华甲虫蒲螨的亚致死数量(LD_(25))、半数致死数量(LD_(50))及幼虫被侵染或寄生后的累计校正死亡率。研究LC_(25)的CFCC81428菌株和LD_(25)的中华甲虫蒲螨对幼虫谷胱甘肽-S-转移酶(GSTs)、乙酰胆碱酯酶(AChE)这2种解毒酶和多酚氧化酶(PPO)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)这3种保护酶的影响。结果表明:菌株CFCC81428对幼虫的毒力更强,其侵染幼虫第10天的LC_(25)、LC_(50)分别为2.04×10_(4)、7.24×10_(5)孢子/mL,幼虫被孢子浓度为108孢子/mL的CFCC81428菌株侵染10 d后的累计校正死亡率为77.30%;中华甲虫蒲螨寄生幼虫第3天的LD_(25)、LD_(50)分别为16.60、25.12头;幼虫被两者联合处理后的累计校正死亡率高于被中华甲虫蒲螨寄生后的累计校正死亡率,联合处理后的僵虫率高于单独感染球孢白僵菌的幼虫僵虫率。幼虫被球孢白僵菌侵染后,2种解毒酶GSTs和AChE活性均高于对照组,处于被诱导状态;幼虫被中华甲虫蒲螨寄生后,其GSTs和AChE活性在60 h前均高于对照组,处于被诱导状态,72 h开始低于对照组,处于被抑制状态;幼虫被联合处理后,其解毒酶活性与其他两个处理组相比呈现进一步下降趋势。幼虫被球孢白僵菌侵染后,3种保护酶PPO、SOD、CAT的活性,除PPO和CAT活性在12 h时低于对照组,其余取样时间均高于对照组,处于被诱导状态;幼虫被中华甲虫蒲螨寄生后,这3种保护酶活性呈现先升高再降低的趋势;幼虫被联合处理后,PPO和CAT活性与其他2个处理组相比呈现提前下降趋势。

In order to study the toxicity and killing effect of Beauveria bassiana and Pyemotes zhonghuajia on Dioryctria abietella,and the detoxification and protective mechanism of D.abietella.The LC_(25)and LC_(50)of B.bassiana strains CFCC81428 and CFCC83116 were determined by insect immersion method and the LD_(25)and LD_(50)of P.zhonghuajia were determined by indoor inoculation,the cumulative corrected mortality of larvae infected or parasitized by them were determined as well.The effects of B.bassiana and P.zhonghuajia undersublethal content(LC_(25))and sublethal dose(LD_(25))on two detoxifying enzymes GSTs and AChE and three protective enzymes CAT,SOD and PPO of larvae were studied.The results showed that the virulence of strain CFCC81428 was stronger to larvae,its LC_(25)and LC_(50)at 10 th day after treatment were 2.04×10^(4)and 7.24×10^(5)spores/mL respectively.The cumulative corrected mortality of larvae infected with strain CFCC81428 with a concentration of 108 spores/mL for 10 d was 77.30%.At 3 rd day after treatments,the LD_(25)and LD_(50)of the parasitic larvae of P.zhonghuajia were 16.60 and 25.12 individuals,respectively.The cumulative corrected mortality of larvae in the combined use of B.bassiana and P.zhonghuajia was higher than that of the larvae treat by P.zhonghuajia alone.The muscardine cadaver rate of larvae in the combined use B.bassiana and P.zhonghuajia was higher than that of larvae infected with B.bassiana only.After the larvae were infected by B.bassiana,detoxification enzyme activities of GSTs and AChE were higher than those of control group,which were in the induced state.The detoxification enzyme activities of GSTs and AChE in the larvae parasitized by the P.zhonghuajia were higher than those in the control group within 60 h after treatment,in the induced state.But it was lower than those in the control group at 72 h after treatment,which was in the inhibited state.The detoxification enzyme activity of the larvae after combined treatment showed a further downward trend compared with the other two treatment groups.The activities of three protective enzymes,PPO,SOD and CAT,in the larvae infected with B.bassiana were all higher than those in the control group showing induced state,except for the activities of PPO and CAT at 12 h after infection.When P.zhonghuajia was used,the larvae activities of these three protective enzymes increased first and then decreased.Comparedwith the other two treatment groups,the activities of PPO and CAT in larva decreased in advance after combined treatment.