Musca domestica L. Diets, Botanical Control of Muscid Flies (Muscidae) and Detection of Escherichia coli from Filth Flies in Local Markets of Hat Yai District, Songkhla Province

Abstract

The house fly, Musca domestica L. (Diptera: Muscidae) is an important insect pest that lives close to humans and can be medically significant as mechanical vectors of different pathogens from unsanitary places to human food. Objectives of this study were to 1) compare larval weight rate and larval nutritionally component of house fly after feeding three different types of larval diet under laboratory conditions 2) determine the insecticidal efficacy and optimal discriminating lethal concentration of Thai essential oils against laboratory strains of M. domestica (larval and adult stages) and adult field population of Stomoxys indicus (Picard), and 3) survey the pathogenic bacteria, Escherichia coli which infected in the filth flies from local markets of Hat Yai, Songkhla Province. For the primary objective, a completely randomized design were performed to compare treatments which included Diet 1: fishery waste - head bone of sea bass, Lates calcarifer (Bloch) and Diet 2: wet commercial cat food to standard Diet of M. musca domestica as a positive control with 10 repetitions for each diet. After 5-d period in each replicate, ten 3rd instar larvae were randomly selected for weight measurement and 150 dried larvae were used for analysis of nutritional composition. By using One-way ANOVA with post-hoc Tukey HSD (Honestly Significant Difference) Test, the mean weights of larvae feeding in Diet 1 (0.41 g/larva) was significantly higher than Diet 2 (0.247 g/larva) and standard Diet (0.253 g/larva). Additionally, percentage of crude fat of larvae in Diet 1 was significant high as larvae in standard Diet, suggested that Diet 1 was an additional option M. domestica diet. The secondary objective was to determine the insecticidal efficacy of native Thai essential oils (clove (Syzygium aromaticum (L.) Merr. & Perry), citronella laurel (Cinnamomum porrectum Kosterm), and pheasant pepper tree (Litsea cubeba Pers)) against larvae and adults of M. domestica, and wild-caught adult of stable fly, Stomoxys indicus. Dipping assays and the World Health Organization cone bioassay system were performed for the larvicidal and adulticidal activities. Cypermethrin and ethyl alcohol were used for the positive and negative control, respectively. Result of larvicidal bioassay showed that 10%v/v of three essential oils gave high percentage of knockdown (KD) and mortality. The lowest concentration of citronella laurel at 6.134%v/v produced the most effective larvicidal activity. For the adulticidal activity of M. domestica, 5% v/v of pheasant pepper tree gave the highest in 100% KD, 93.33% mortality, and LC50 of 3.82%. For adulticide activity on S. indicus, clove oil gave the highest LC50 value at 0.284%. A survey of the pathogenic bacteria, E. coli infected in filth flies from local markets in Hat Yai District, Songkhla Province exhibited the positive result for M. domestica, M. autumnalis, and M. crassirostris in family Muscidae. So, this study confirmed that muscid flies are a mechanical transmitter of coliform bacteria and E. coli to humans. These findings in this study suggested that larvae of house flies could be used for biodegradation of fishery waste. Citronella laurel and pheasant pepper tree oil could be used for larval and adult M. domestica control, respectively, while clove oil was the most efficacy to control adult S. indicus. Muscid flies in local market of Hat Yai District, Songkhla Province were contaminated with E. coli despite having no differentiating bacterial species.