Studies indicat that; 1. when soil moisture is above 15% and soil temperature is 20-28℃ ,the condition is benefic for infecting and reproducing of the nematodes. At the same time,this condition is samely needed for t...Studies indicat that; 1. when soil moisture is above 15% and soil temperature is 20-28℃ ,the condition is benefic for infecting and reproducing of the nematodes. At the same time,this condition is samely needed for the white grubs; 2. the migration ability of the nematodes is lower in soil of field than that in tested soil of the laboratory. But in general,the nematodes appplyed into soil distribute mainly in the ploughed layer and a migration area for them can be formed in the direction of horizontal; 3. observations reveal that invasion time of the S. glaseri NC34 into larval (H. parallela) through intersegmental membrane of body segment and foot after the inoculation is 30 min,and it for invading cuticle of larvae body side is 120 min. But the infection time is different in the different individuals of S. glaseri and in the different species of grubs.展开更多
Background The emergence of pink bollworm(PBW),Pectinophora gossypiella(Saunders)(Lepidoptera:Gelechiidae),in cotton due to Bt resistance and concealed feeding habit has created a need for alternative,eco-friendly,and...Background The emergence of pink bollworm(PBW),Pectinophora gossypiella(Saunders)(Lepidoptera:Gelechiidae),in cotton due to Bt resistance and concealed feeding habit has created a need for alternative,eco-friendly,and cost-effective control methods.This study aimed to evaluate the bio-efficacy and reproductive potential of two native strains of entomopathogenic nematodes(EPNs),Heterorhabditis indica,namely CICR-HI-CL and CICR-HI-MN,against PBW larvae and pupae under in-vitro conditions.Results The larval assay revealed that strain CICR-HI-CL exhibited higher potency than strain CICR-HI-MN against 2nd,3rd,and 4thinstar larvae,with median lethal dose(LD50)values of 5.45,4.45,and 4.60 infective juveniles(IJs)per larva,respectively.In case of pupal bioassay,both EPN strains demonstrated greater virulence when applied directly(LD50values:29.65 and 73.88 IJs per pupa for strains CICR-HI-CL and CICR-HI-MN,respectively)compared to soil application(147.84 and 272.38 IJs per pupa).Both EPN strains successfully penetrated and reproduced on 4thinstar larvae,resulting in maximum production of 19.28 and 20.85 lakh IJs per larva in the next generation when inoculated at 30 IJs per larva.Conclusion The present study has generated useful information on the virulence and reproductive potential of two strains of EPN H.indica(CICR-HI-CL and CICR-HI-MN)against PBW,a dreaded pest of cotton.Higher virulence and reproductive potential of EPN strains demonstrated their ability to multiply,sustain and perpetuate on larval and pupal stages of PBW.The knowledge generated will help formulate effective management strategies for PBW with the inclusion of EPN as a potential biological control candidate.The soil-dwelling life stages viz.,last instar hibernating larvae and pupae of PBW can be the ideal weak links to make a successful use of H.indica for sustainable management of PBW in the cotton ecosystem.However,before taking these EPN strains to field for managing PBW,detailed studies investigating their biocontrol potential against PBW under field conditions are needed.展开更多
文摘Studies indicat that; 1. when soil moisture is above 15% and soil temperature is 20-28℃ ,the condition is benefic for infecting and reproducing of the nematodes. At the same time,this condition is samely needed for the white grubs; 2. the migration ability of the nematodes is lower in soil of field than that in tested soil of the laboratory. But in general,the nematodes appplyed into soil distribute mainly in the ploughed layer and a migration area for them can be formed in the direction of horizontal; 3. observations reveal that invasion time of the S. glaseri NC34 into larval (H. parallela) through intersegmental membrane of body segment and foot after the inoculation is 30 min,and it for invading cuticle of larvae body side is 120 min. But the infection time is different in the different individuals of S. glaseri and in the different species of grubs.
基金the Indian Council of Agricultural Research,New Delhi for the grant in aid through ICAR-Central Institute for Cotton Research,Nagpur Institutional Project。
文摘Background The emergence of pink bollworm(PBW),Pectinophora gossypiella(Saunders)(Lepidoptera:Gelechiidae),in cotton due to Bt resistance and concealed feeding habit has created a need for alternative,eco-friendly,and cost-effective control methods.This study aimed to evaluate the bio-efficacy and reproductive potential of two native strains of entomopathogenic nematodes(EPNs),Heterorhabditis indica,namely CICR-HI-CL and CICR-HI-MN,against PBW larvae and pupae under in-vitro conditions.Results The larval assay revealed that strain CICR-HI-CL exhibited higher potency than strain CICR-HI-MN against 2nd,3rd,and 4thinstar larvae,with median lethal dose(LD50)values of 5.45,4.45,and 4.60 infective juveniles(IJs)per larva,respectively.In case of pupal bioassay,both EPN strains demonstrated greater virulence when applied directly(LD50values:29.65 and 73.88 IJs per pupa for strains CICR-HI-CL and CICR-HI-MN,respectively)compared to soil application(147.84 and 272.38 IJs per pupa).Both EPN strains successfully penetrated and reproduced on 4thinstar larvae,resulting in maximum production of 19.28 and 20.85 lakh IJs per larva in the next generation when inoculated at 30 IJs per larva.Conclusion The present study has generated useful information on the virulence and reproductive potential of two strains of EPN H.indica(CICR-HI-CL and CICR-HI-MN)against PBW,a dreaded pest of cotton.Higher virulence and reproductive potential of EPN strains demonstrated their ability to multiply,sustain and perpetuate on larval and pupal stages of PBW.The knowledge generated will help formulate effective management strategies for PBW with the inclusion of EPN as a potential biological control candidate.The soil-dwelling life stages viz.,last instar hibernating larvae and pupae of PBW can be the ideal weak links to make a successful use of H.indica for sustainable management of PBW in the cotton ecosystem.However,before taking these EPN strains to field for managing PBW,detailed studies investigating their biocontrol potential against PBW under field conditions are needed.
文摘番茄潜叶蛾Tuta absoluta是一种世界性入侵性害虫,起源于南美洲,主要危害茄科作物。当前,番茄潜叶蛾主要防控手段为化学防治,但化学防治易引起害虫抗药性水平升高,对环境、非靶标物种造成危害,甚至还给人类身体健康带来负面影响。因此,环境友好的生物防治技术成为当前的研究热点,在多个国家和地区已经将生物防治技术用于番茄潜叶蛾防控。昆虫病原线虫(Entomopathogenic nematodes,EPNs)是害虫生物防治的常用生防作用物,也是害虫综合治理(Integrative Pest Management,IPM)策略中的重要组成部分。目前,关于利用昆虫病原线虫开展番茄潜叶蛾生物防治的研究内容比较零散,本研究系统梳理了全球范围内利用EPNs防治番茄潜叶蛾的研究进展,并从以下几个部分进行了综述:(1)昆虫病原线虫的分类及生物学特性;(2)应用昆虫病原线虫防治番茄潜叶蛾研究进展;(3)环境因素对昆虫病原线虫防效的影响;(4)昆虫病原线虫与其他防控措施联合施用技术。本文总结了提高利用昆虫病原线虫防控番茄潜叶蛾效力的方法,并对利用昆虫病原线虫防控番茄潜叶蛾的研究提出了展望。
