Objective：Mosquitoes are the major transmitting vectors of serious human diseases,causing millions of deaths every year with undesirable effects,including toxicity to non-target organisms.Some plants with insecticida...Objective：Mosquitoes are the major transmitting vectors of serious human diseases,causing millions of deaths every year with undesirable effects,including toxicity to non-target organisms.Some plants with insecticidal properties have been used in recent years for the control of a variety of pest insects and vectors.In the quest for alternative natural biological control agents against mosquito larvae lichens were selected.Method：Larvicidal activity was assessed with methanolic extracts of Parmotrema reticulatum,Parmotrema kamatti,Parmotrema tinctorum,Parmelia erumpens,Leptogium papilosum,and Roccella montagnei against Aedes aegypti,Anopheles stephensi,and Culex quinquefasciatus.The standard WHO protocols with minor modifications were adopted and the bioassay was evaluated at the concentrations of 100–500μg/m L for each lichen.Since all the lichen extracts showed complete mortality against C.quinquefasciatus in100μg/m L,the concentrations were decreased to 100,50,25,12.5,and 6.25μg/m L for C.quinquefasciatus.Larval mortality was observed for 24 h after treatment.Results：All the lichen extracts exhibited activity against third instar larvae of A.aegypti and A.stephensi at 100μg/m L,and 100%mortality was observed against the vector C.quinquefasciatus at 100μg/m L.The highest larvicidal activity was found with L.papilosum against A.aegypti（81.127μg/m L）and A.stephensi（89.10μg/m L）.Similarly,P.tinctorum and R.montagnei when tested against C.quinquefasciatus with minimum concentration〈100μg/m L exhibited significant activity withof 5.32and 6.97μg/m L.Conclusion：The bioassay results revealed larvicidal potential of lichens especially against C.quinquefasciatus with high mortality even at lower concentration.Hence,lichens can be used as an ideal sustainable approach for the control of lymphatic filariasis caused by vector C.quinquefasciatus.展开更多
文摘Objective：Mosquitoes are the major transmitting vectors of serious human diseases,causing millions of deaths every year with undesirable effects,including toxicity to non-target organisms.Some plants with insecticidal properties have been used in recent years for the control of a variety of pest insects and vectors.In the quest for alternative natural biological control agents against mosquito larvae lichens were selected.Method：Larvicidal activity was assessed with methanolic extracts of Parmotrema reticulatum,Parmotrema kamatti,Parmotrema tinctorum,Parmelia erumpens,Leptogium papilosum,and Roccella montagnei against Aedes aegypti,Anopheles stephensi,and Culex quinquefasciatus.The standard WHO protocols with minor modifications were adopted and the bioassay was evaluated at the concentrations of 100–500μg/m L for each lichen.Since all the lichen extracts showed complete mortality against C.quinquefasciatus in100μg/m L,the concentrations were decreased to 100,50,25,12.5,and 6.25μg/m L for C.quinquefasciatus.Larval mortality was observed for 24 h after treatment.Results：All the lichen extracts exhibited activity against third instar larvae of A.aegypti and A.stephensi at 100μg/m L,and 100%mortality was observed against the vector C.quinquefasciatus at 100μg/m L.The highest larvicidal activity was found with L.papilosum against A.aegypti（81.127μg/m L）and A.stephensi（89.10μg/m L）.Similarly,P.tinctorum and R.montagnei when tested against C.quinquefasciatus with minimum concentration〈100μg/m L exhibited significant activity withof 5.32and 6.97μg/m L.Conclusion：The bioassay results revealed larvicidal potential of lichens especially against C.quinquefasciatus with high mortality even at lower concentration.Hence,lichens can be used as an ideal sustainable approach for the control of lymphatic filariasis caused by vector C.quinquefasciatus.
