Evaluation of Filth Fly Species Composition and Abundance Using Two Monitoring Methods in Swine Confinement Housing

Landscape distribution and abundance of animal-associated adult filth flies on commercial swine facilities in North Carolina, US

Filth flies associated with animal production transmit pathogens to humans and animals, propagate antimicrobial resistance in microbial communities and provoke nuisance litigation. Although dispersal of flies from facilities is often responsible for these negative effects, filth fly research on swine facilities has been limited to within the barns. Filth fly adaptations in space and time, as well as influences of abiotic and biotic factors impact distribution and abundance of animal-associated filth flies on swine production facilities. In this study, fly surveillance was conducted around four swine facilities in Bladen County, North Carolina, U.S.A. from January 2019 to October 2019. Traps were replaced weekly and animal-associated filth flies were identified. Flies were grouped for comparison based on biology and differences in pest management strategies. There were distinct differences in abundance and spatial distribution of different filth fly groups on the swine facilities, which are likely linked to environmental factors like spatial relation to crop production and species phenology. The impact of the observed temporal and spatial distribution and abundance is discussed in the context of filth fly management.

Review of Methods to Monitor House Fly (Musca domestica) Abundance and Activity

The house fly is a ubiquitous pest commonly associated with animal facilities and urban waste. When present in large numbers, house flies can negatively impact humans and animals through nuisance and the transmission of pathogens. Since the development of fly traps and sticky papers to capture flies in the late 1800s, these and other methods have been used as a means to monitor change in house fly density or fly activity over time. Methods include substrate sampling to record density of immature flies, visual observations of adult fly activity, instantaneous counts of landing or resting flies, accumulation of adult flies on/in traps, or accumulation of fly fecal and regurgitation spots deposited by flies onto white cards. These methods do not estimate true house fly density, but rather provide an index of house fly activity that is related to both fly density and the frequency of individual fly behavior (e.g., frequency of flight, landing events) and which is likely more predictive of negative impacts such as nuisance and pathogen transmission. Routine monitoring of house fly activity is a critical component of a house fly management program. Fly activity should be held to a level below a predetermined activity threshold ('action threshold') above which negative impacts are anticipated to occur. This article is a review of methods utilized for monitoring house fly (Diptera: Muscidae) activity.

Monitoring House Fly (Diptera: Muscidae) Activity on Animal Facilities

Monitoring house fly (Diptera: Muscidae) activity on animal facilities is a necessary component of an integrated pest management (IPM) program to reduce the negative impacts of these flies. This article describes monitoring methods appropriate for use on animal facilities with discussion of monitoring device use and placement. Action thresholds are presented where these have been suggested by researchers. Sampling precision is an important aspect of a monitoring program, and the number of monitoring devices needed to detect a doubling of fly activity is presented for monitoring methods where this information is available. It should be noted that both action thresholds and numbers of monitoring devices will be different for every animal facility. Suggested action thresholds and numbers of monitoring devices are presented only to provide guidance when initiating a fly monitoring program. Facility managers can adjust these values based upon the fly activity data recorded at their facility. Spot cards are generally recommended as an easy-to-use method for monitoring fly activity for most animal facilities. Fly ribbons or similar sticky devices are recommended where several pest fly species may be abundant and identifying the activity of each species is important, but a sampling period of <7 d may be needed in dusty conditions or when fly density is high. Fly ribbons are not recommended for outdoor use. Insecticide-baited traps may be used in outdoor locations where environmental conditions limit the use of spot cards, fly ribbons, and sticky traps.