Screening of methods for determining bioactivity of insecticides against Carpophilus dimidiatus
[Aims]This study aims to screen sensitive methods of bioassay for adults and larvae of Carpophilus dimidiatus,a new pest to macadamia nut.[Methods]The experiment was carried out using emamectin benzoate as tested insecticide by 3 methods,namely,immersion method,feeding method and insecticide-membrane method.[Results]24 Hours after treatment,the immersion method had the best activity to adults of C.dimidiatus with an LC50 of 28.48 mg/L,which was significantly higher than insecticide-membrane method with an LC50 of 206.81 mg/L and feeding method with an LC50 of 343.80 mg/L.The feeding method had the best activity to 2nd instar larvae of C.dimidiatus with an LC50 of 44.30 mg/L,which was significantly higher than insecticide-membrane method with an LC50 of 144.81 mg/L and immersion method with an LC50 of 142.27 mg/L.[Conclusions]The Immersion method can be used to test activity of insecticides against adults of C.dimidiatus,and feeding method can be used against larvae of C.dimidiatus.The conclusion provides a reference for selection of sensitive method to determine the activity of insecticides against adults and larvae of C.dimidiatus.