黄氏枝膜叶蜂生物学特性及金龟子绿僵菌对其幼虫的致病力

Biological characteristics of Cladiucha huangbki(Hymenoptera:Tenthredinidae)and pathogenicity of Metarhizium anisopliae against its larvae

【目的】黄氏枝膜叶蜂Cladiucha huangbki是新发现的叶蜂科(Tenthredinidae)枝膜叶蜂属Cladiucha种类,以幼虫取食危害乳源木莲Manglietia yuyuanensis叶片,虫口密度大,严重影响乳源木莲的生长。本研究旨在明确该虫的生物学特性,并筛选出对该虫具有高致病力的金龟子绿僵菌Metarhizium anisopliae菌株,为高效治理该虫提供理论基础和生物防治资源。【方法】以林间调查和室内饲养观察相结合的方式,观察黄氏枝膜叶蜂的各发育阶段形态特征和生物学特性(寄主植物、分布和生活史);采用孢子悬浮液喷雾法筛选高致病力金龟子绿僵菌菌株。【结果】林间和室内观察结果表明,黄氏枝膜叶蜂幼虫取食木兰科木莲属植物,在福建永安市一年发生1代,以老熟幼虫(预蛹)在土室中越夏、越冬;翌年3月上旬化蛹,3月下旬成虫羽化,4月上旬为雌虫产卵高峰期,4月中旬幼虫出现,4月下旬至5月上旬为幼虫危害高峰期,5月中旬老熟幼虫开始入土做土室,入土深度30~150 mm。室内金龟子绿僵菌不同菌株对黄氏枝膜叶蜂幼虫致病力测定结果表明,以1×10^(7)孢子/mL悬浮液喷雾11 d后,不同菌株对其幼虫的校正死亡率均超过85%,其中MaQZ-01,MaYTTR-04-05,Ma3和MaFZ-134个菌株感染的叶蜂幼虫校正死亡率为100%。菌株MaFZ-08感染引起的黄氏枝膜叶蜂僵虫率最高,为60%;其次是MaYTTR-04-05,引起的僵虫率为50%。金龟子绿僵菌各菌株对黄氏枝膜叶蜂幼虫的致死中时间(LT50)相差不大,在6 d左右,其中MaYTTR-04-05菌株的LT50最短,为5.090 d。【结论】黄氏枝膜叶蜂在福建永安一年发生1代,5月中、下旬老熟幼虫入土做土室化为预蛹越夏越冬。本研究筛选出对黄氏枝膜叶蜂幼虫致病力强的金龟子绿僵菌MaYTTR-04-05菌株,在其防治上有良好的应用前景。

【Aim】Cladiucha huangbki is a newly identified sawfly of Cladiucha of Tenthredinidae.Its larvae feed on leaves of Manglietia yuyuanensis with large population density and cause serious damage.This study aims to clarify the biological characteristics of C.huangbki and screen out the high pathogenicity strains of Metarhizium anisopliae against this sawfly,so as to provide theoretical basis and strain resources for the biological control of this insect pest.【Methods】The morphological and biological characteristics of various developmental stages of C.huangbki including host plants,distribution,and life history were observed in both the laboratory and field.High pathogenic strains of M.anisopliae against this insect pest were screened by using spraying spore suspension.【Results】The results of field and laboratory observations showed that C.huangbki larvae feed on Manglietia plants of Magnoliaceae.C.huangbki has only one generation each year in Yong′an City,Fujian Province.Mature larvae(prepupae)oversummer and overwinter in the soil chamber and start to pupate in early March of the next year.Adults begin to emerge in late March,and female adults reach the oviposition peak in early April.Larvae are hatched in mid-April and cause enormous damage in late April to early May.Mature larvae burrow into soil in the depth of 30-150 mm to make soil chambers in mid-May.The results of pathogenicity test showed that the corrected mortality rates of C.huangbki caused by the suspension of all the tested strains of M.anisopliae at the concentration of 1×10^(7) spores/mL were over 85%at 11 d post inoculation,and the strains MaQZ-01,MaYTTR-04-05,Ma3 and MaFZ-13 caused the larval corrected mortality rates of 100%.The strain MaFZ-08 caused the highest cadaver rate of C.huangbki(60%),followed by MaYTTR-04-05,causing the cadaver rate of 50%.The median lethal time(LT50)values of various strains of M.anisopliae to C.huangbki larvae were about 6 d,showing little difference between different strains,while the LT50 value of MaYTTR-04-05 to C.huangbki larvae was the shortest,being 5.090 d.【Conclusion】C.huangbki has only one generation each year in Yong′an,Fujian,and mature larvae burrow into soil to make soil chambers for oversummering and overwintering of prepupae after early-May.The strain MaYTTR-04-05 screened out in this study shows high pathogenicity to C.huangbki larvae,and has a good application value in the control of this insect pest.