In Denmark,the weevils Strophosoma melanogrammum and S.capitatum cause economic damage in Noble fir due to the adult stage feeding on the needles.No chemical treatments of these weevils are allowed in Denmark,so biolo...In Denmark,the weevils Strophosoma melanogrammum and S.capitatum cause economic damage in Noble fir due to the adult stage feeding on the needles.No chemical treatments of these weevils are allowed in Denmark,so biological control is an attractive solution.We evaluated the potential for microbial control of larvae of Strophosoma spp.based on laboratory bioassays and field applications,taking effect on both target and non-target into consideration,as well as persistence of the applied fungus.In the laboratory Beauveria bassiana,Paecilomyces farinosus and Metarhizium anisopliae were able to infect and cause mycosis in Strophosoma larvae.Among the tested isolates the most virulent isolate was M.anisopliae BIPESCO 5,which resulted in 80 % mortality.In the field experiment M.anisopliae,isolate BIPESCO 5,was applied to the soil as a conidial suspension against larvae of Strophosoma spp.The effect of the fungus on the target population was monitored at a weekly basis by counts of emerging adult weevils during their activity periods.The population of Strophosoma spp.was reduced by up to 60% in treated plots compared to control plots.The non-target effects of M.anisopliae were studied by sampling insects and ticks from both treated and control plots.Seven days after treatment,two sampled insect orders(Hemiptera and Coleoptera)and ticks were found with prevalences of M.anisopliae above 50%,compared to no infection in the insects collected from control plots.Infections in coccinellids were found as long as 277 days after treatment.However,the effect on population level of non-target is still unexplored.The persistence of the fungus was documented by plating a soil suspension onto agar.We documented that conidia of M.anisopliae could persist in the greenery plantation for at least 418 days after application.展开更多
文摘In Denmark,the weevils Strophosoma melanogrammum and S.capitatum cause economic damage in Noble fir due to the adult stage feeding on the needles.No chemical treatments of these weevils are allowed in Denmark,so biological control is an attractive solution.We evaluated the potential for microbial control of larvae of Strophosoma spp.based on laboratory bioassays and field applications,taking effect on both target and non-target into consideration,as well as persistence of the applied fungus.In the laboratory Beauveria bassiana,Paecilomyces farinosus and Metarhizium anisopliae were able to infect and cause mycosis in Strophosoma larvae.Among the tested isolates the most virulent isolate was M.anisopliae BIPESCO 5,which resulted in 80 % mortality.In the field experiment M.anisopliae,isolate BIPESCO 5,was applied to the soil as a conidial suspension against larvae of Strophosoma spp.The effect of the fungus on the target population was monitored at a weekly basis by counts of emerging adult weevils during their activity periods.The population of Strophosoma spp.was reduced by up to 60% in treated plots compared to control plots.The non-target effects of M.anisopliae were studied by sampling insects and ticks from both treated and control plots.Seven days after treatment,two sampled insect orders(Hemiptera and Coleoptera)and ticks were found with prevalences of M.anisopliae above 50%,compared to no infection in the insects collected from control plots.Infections in coccinellids were found as long as 277 days after treatment.However,the effect on population level of non-target is still unexplored.The persistence of the fungus was documented by plating a soil suspension onto agar.We documented that conidia of M.anisopliae could persist in the greenery plantation for at least 418 days after application.
