First Evaluation of Field Evolved Resistance to Commonly Used Insecticides in House Fly Populations from Saudi Arabian Dairy Farms

Abdulwahab M Hafez

doi:10.3390/insects12121120

Abstract

Simple SummaryThe house fly is one of the major carriers of several diseases that affect humans and animals. Insecticides are often used as a rapid method to control them. In this study, eight commonly used insecticides were tested against five populations of house flies collected from dairies around Riyadh, Saudi Arabia. The aim was to evaluate how toxic the insecticides were, and to find out whether the flies showed any sign of resistance against insecticides. In the tested pyrethroid insecticides, there was no or only moderate resistance in adults of both sexes compared to a known susceptible strain. In the tested organophosphate insecticides, there was low to moderate resistance in adults of both sexes compared to the susceptible strain. This study also evaluated “median lethal times” for the tested insecticides (how long a certain dose takes to kill half the exposed population), with results available for all eight insecticides: alpha-cypermethrin, deltamethrin, bifenthrin, cypermethrin, cyfluthrin, fenitrothion, chlorpyrifos, and malathion. The results of this study will be helpful for people whose job it is to plan effective house fly control programs in Saudi Arabia.The house fly, Musca domestica L. (Diptera: Muscidae), is one of the major vectors of several pathogens that affect humans and animals. We evaluated the toxicity of eight insecticides commonly used for house fly control using five field populations collected from dairies in Riyadh, Saudi Arabia. Among the five tested pyrethroids, non to moderate resistance was found in adults of both sexes compared to a susceptible strain. Resistance ratios ranged from 0.5- to 7-fold for alpha-cypermethrin, 2- to 21-fold for deltamethrin, 4- to 19-fold for bifenthrin, 1- to 9-fold for cyfluthrin, and 1- to 8-fold for cypermethrin. Among the three tested organophosphates, low to moderate resistance was found among adult flies compared to the susceptible strain, and the resistance ratios ranged from 4- to 27-fold for fenitrothion, 2- to 14-fold for chlorpyrifos, and 3- to 12-fold for malathion. The median lethal times for the tested insecticides were 3–33 h for alpha-cypermethrin, 3–24 h for deltamethrin, 5–59 h for bifenthrin, 1–7 h for cypermethrin, 0.3–7 h for cyfluthrin, 6–36 h for fenitrothion, 2–21 h for chlorpyrifos, and 3–34 h for malathion. This study presents baseline data pertaining to registered public health insecticides, and the results will assist future studies monitoring insecticide resistance, and the planning of effective integrated vector management programs.

Highlights

The domestic house fly, Musca domestica L. (Diptera: Muscidae), is a major insect pest in rural and urban areas worldwide [1,2,3,4]
Over the past few decades, over-reliance on synthetic insecticides has resulted in the house fly developing resistance to these two classes of insecticide, increasing the challenges for insect pest management [8,9,10,11]
Synthetic chemicals have been recommended for the management various pests, including house flies, in Saudi Arabia [26]

Summary

Introduction

The domestic house fly, Musca domestica L. (Diptera: Muscidae), is a major insect pest in rural and urban areas worldwide [1,2,3,4]. (Diptera: Muscidae), is a major insect pest in rural and urban areas worldwide [1,2,3,4]. Overuse of insecticides has resulted in environmental pollution, increased the cost of preventive control, and caused destruction of non-target organisms [12,13]. These issues emphasize the necessity to employ an integrated pest management program against insect pests, including the house fly [14,15,16]. To overcome the development of resistance, excessive applications of insecticides at increasing dose rates and more frequent intervals have been used, but these practices have escalated the problem and rendered the control of house fly even more difficult all over the world, in areas where most suitable insecticides have lost their efficacy [17]

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