荧光素对舞毒蛾核型多角体病毒不同地理品系的增效与光保护作用

舞毒蛾Lymantria dispar L.是源于欧亚大陆的多食性叶部害虫,取食300多种乔灌木,现已分布于北美、北非,成为世界性危险害虫之一,给林业生产带来了巨大损失。舞毒蛾核型多角体病毒(LdMNPV)是控制舞毒蛾种群动态的重要生物因素,可引起舞毒蛾种群急剧下降。在室内采用青杨枝条饲养的方法,测定了来自中国、北美和日本的3个LdMNPV品系(分别为LdMNPV-H,LdMNPV-D和LdMNPV-J)对危害青杨的亚洲型舞毒蛾幼虫的毒力,并测定了荧光素Tinopal LPW对它们的增效和光保护作用。结果表明Tinopal LPW对LdMNPV 3个地理品系均有增效和光保护作用,而且随着Tinopal LPW浓度的增加,增效作用增强,1%Tinopal LPW的增效作用最好。添加1%Tinopal LPW的LdMNPV-D品系、LdMNPV-H品系和LdMNPV-J品系对取食青杨的舞毒蛾幼虫的致死中浓度(LC50)分别为1.0、1.6、17.6 OBs/μL,不添加1%Tinopal LPW时,它们的LC50分别为32.9、39.0、1076.4 OBs/μL,分别降低了33、24、61倍。不添加1%Tinopal LPW时,D、H和J品系对舞毒蛾二龄幼虫的致LC95分别是2125.5、1275.8、303540.0 OBs/μL,添加1%Tinopal LPW后LC95分别为73.0、285.4、2360.8OBs/μL,分别降低了26、4.5、128.6倍。此外,1%Tinopal LPW的荧光素使3个品系的致死中时间(LT50)分别缩短了2.9d、5.3d、1.2d。LdMNPV-D和LdMNPV-H品系对亚洲型舞毒蛾表现出低致死中浓度、较短的致死中时间和较大的斜率,二者的毒力较LdMNPV-J品系高,在生产实践中应选择LdMNPV-D添加1%Tinopal LPW。Tinopal LPW对LdMNPV-D、LdMNPV-H和LdMNPV-J 3个品系均有光保护作用,添加1%Tinopal LPW后在距离30W紫外灯40cm下照射16h后,它们毒力保持系数比未添加Tinopal LPW分别高1.8、2.6、1.8倍。

The synergistic action and UV protection of optical brightener on three different geographic isolates of Asian Gypsy Moth Nucleopolyhedrovirus (LdMNPV)

The gypsy moth,Lymantria dispar L.(Lepidoptera: Lymantriidae),is a polyphagous defoliator of Eurasian origin known to feed on over 300 species of trees and shrubs and distributed in North America and North Africa at present.It′s one of the most serious insect pests causing great economic losses on forest production.Gypsy moth nucleopolyhedrovirus(LdMNPV) plays an important regulatory role and is one of the major factors controlling L.dispar populations and often causes the population collapse.Three isolates of gypsy moth virus from China(LdMNPV-H),Japan(LdMNPV-J) and the registered strain from North America(LdMNPV-D) were evaluated on the virulence against the 2nd instar Asian gypsy moth larvae fed on poplar at laboratory.Tinopal LPW,a UV protection brightener,was added into the solution of LdMNPV isolates to compare the virulence against the same instar larvae.UV protection of Tinopal LPW was tested using a UV lamplight(30W) radiation.The results showed that Tinopal LPW could enhance the biological activity of the virus,and the higher concentration of Tinopal LPW,the higher activity of the virus.The optimal concentration of Tinopal LPW was 1%.The results also indicated that LdMNPV-D and LdMNPV-H did not differ significantly in LC50 when tested against the Asian gypsy moth larvae fed on poplar(Popul uscathayana) regardless of adding the brightener of Tinopal LPW.LdMNPV-J and LdMNPV-D differed significantly in LC50,and so did LdMNPV-J and LdMNPV-H.The LC50s of LdMNPV-D,LdMNPV-H and LdMNPV-J with 1% Tinopal LPW were 1.0,1.6 and 17.6 OBs/μL,respectively,whereas those without 1%Tinopal LPW were 32.9,39.0 and 1076.4 OBs/μL,respectively.The LC95s of LdMNPV-D,LdMNPV-H and LdMNPV-J with 1% Tinopal LPW were 73.0、285.4 and 2360.8Bs/μL,respectively,whereas those without 1%Tinopal LPW were 2125.5、1275.8 and 303540.0 OBs/μL,respectively.The virulence of the three isolates were increased 33,24 and 61 times by 1%Tinopal LPW in LC50,respectively.In addition,the LT50s of the three isolates with 1%Tinopal LPW were 2.9d,5.3d and 1.2d shorter than those without 1%Tinopal LPW.LdMNPV-H and LdMNPV-D showed lower LC50,shorter LT50 and bigger slopes against Asian gypsy moth,and their virulences were higher than that of LdMNPV-J.LdMNPV-D with 1% Tinopal LPW should be chosen to use in practice.1%Tinopal LPW had UV radiation protection on the LdMNPV isolates.After 16 hours exposure to a 30W UV lamplight at a distance of 40cm,the virulences of LdMNPV-D,LdMNPV-H and LdMNPV-J with 1% Tinopal LPW were 1.8,2.6 and 1.8 times higher than those without 1% Tinopal LPW,respectively.