title: Risk assessment, cross-resistance potential, and biochemical mechanism of resistance to emamectin benzoate in a field strain of house fly (Musca domestica Linnaeus).
abstract: Reduced sensitivity to insecticides in insect pests often results in control failures and increases in the dose and frequency of applications, ultimately polluting the environment. Reduced sensitivity to emamectin benzoate, a broad-spectrum agrochemical belonging to the avermectin group of pesticides, was reported in house flies (Musca domestica L.) collected from Punjab, Pakistan, in 2013. The aim of the present study was to investigate the risk for resistance development, biochemical mechanism, and cross-resistance potential to other insecticides in an emamectin benzoate selected (EB-SEL) strain of house flies. A field-collected strain showing reduced sensitivity to emamectin was re-selected in the laboratory for five consecutive generations and compared with a laboratory susceptible (Lab-Susceptible) reference strain, using bioassays. The field strain showed rapid development of resistance to emamectin (resistance ratio (RR) increased from 35.15 to 149.26-fold) as a result of selection experiments; however, resistance declined when the selection pressure uplifted. The EB-SEL strain showed reduction in resistance to abamectin, indoxacarb, and thiamethoxam. The results of synergism experiments using piperonyl butoxide (PBO) and S,S,S-tributylphosphorotrithioate (DEF) enzyme inhibitors and biochemical analyses revealed that the metabolic resistance mechanism was not responsible in developing emamectin resistance in the EB-SEL strain. In conclusion, the risk for the rapid development of emamectin resistance under continuous selection pressure suggests using a multifaceted integrated pest management approach for house flies. Moreover, the instable nature of emamectin resistance in the EB-SEL strain and lack of cross-resistance to other insecticides provide windows for the rotational use of insecticides with different modes of action. This will ultimately reduce emamectin selection pressure and help improving management programs for house flies without polluting the environment.
authors.affiliation: Institute of Agricultural Sciences, University of the Punjab, Lahore, Pakistan. Electronic address: azhar_naturalist@yahoo.com.
authors.forename: Hafiz Azhar Ali
authors.initials: HA
authors.lastname: Khan
authors.affiliation: Department of Entomology, University of Agriculture, Faisalabad, Pakistan.
authors.forename: Waseem
authors.initials: W
authors.lastname: Akram
authors.affiliation: Institute of Agricultural Sciences, University of the Punjab, Lahore, Pakistan.
authors.forename: Tiyyabah
authors.initials: T
authors.lastname: Khan
authors.affiliation: Institute of Agricultural Sciences, University of the Punjab, Lahore, Pakistan.
authors.forename: Muhammad Saleem
authors.initials: MS
authors.lastname: Haider
authors.affiliation: Department of Plant Protection, Ghazi University, Dera Ghazi Khan, Pakistan.
authors.forename: Naeem
authors.initials: N
authors.lastname: Iqbal
authors.affiliation: Department of Entomology, University of Agriculture, Faisalabad, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Zubair
mesh_terms: D000818:Animals; D006793:Houseflies / Q000187:drug effects*; D007305:Insecticide Resistance / Q000187:drug effects*; D007306:Insecticides / Q000494:pharmacology*; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000494:pharmacology; D010154:Pakistan; D010882:Piperonyl Butoxide / Q000494:pharmacology; D018570:Risk Assessment
chemical_list: D007306:Insecticides; D007559:Ivermectin; C108024:emamectin benzoate; D010882:Piperonyl Butoxide
keywords: Ecotoxicology; Environmental pollution; New chemicals