LABORATORY TOXICITY OF MOSQUITO ADULTICIDES TO THE ASIAN TIGER MOSQUITOES, AEDES ALBOPICTUS AND THE HONEY BEES, APIS MELLIFERA

Resumo

Aedes albopictus and Apis mellifera were exposed to six insecticide active ingredients and five commercial insecticide formulations by topical application and insecticide-impregnated paper strips respectively to determine the differential toxicity and the potential use of the two methods in insecticide resistance monitoring surveys. By topical application deltamethrin was the most toxic active ingredient (LD 50 = 0.018 µg/g) for Ae. albopictus whereas chlorpyrifos was the least toxic (LD 50 = 0.499 µg/g). For Apis mellifera, the most toxic active ingredients were bifenthrin (LD 50 = 0.047 µg/g) and deltamethrin (LD 50 = 0.055 µg/g) while chlorpyrifos (LD 50 = 0.215 µg/g) and permethrin (LD 50 = 0.287 µg/g) had comparatively low toxicity. When the insecticide-impregnated method was used, Mosquito Mist (a.i. chlorpyrifos) was the most toxic commercial formulation for both Ae. albopictus (LC50 = 0.028 µg/cm2 ) and A. mellifera (LC50 = 0.059 µg/ cm2 ). Duet and DeltaGard showed the least toxicity (LC50 = 2.429 µg/cm 2 and LC50 = 0.491 µg/cm 2 respectively) for Ae. albopictus and DeltaGard was the least toxic to A. mellifera (LC50 = 18.09 µg/cm2 ).

When using the topical application method with insecticide active ingredients, more than 3 times permethrin and deltamethrin were required to obtain the same mortality rate in A. mellifera as in Ae. albopictus. However, chlorpyrifos was more toxic for A. mellifera than for Ae. albopictus. In the insecticide-impregnated paper-strip method with commercial insecticide formulations, more than 36 times of DeltaGard was required to obtain the same mortality rate in A. mellifera as in Ae. albopictus. Even though the Mosquito Mist is the most toxic commercial formulation for both insect species, A. mellifera were more than 2 times tolerant to this insecticide compared to Ae. albopictus.

The study concludes the active ingredient deltamethrin or its commercial formulation DeltaGard is the best among tested insecticides to control Ae. albopictus with minimal effects to A. mellifera.