S1006: Insect and Manure Management in Poultry Systems: Elements Relative to Food Safety and Nuisance Issues (S274)
- Duration:
- October 01, 2001 to September 30, 2006
- Administrative Advisor(s):
-
Richard Roeder
(ARK)
- NIFA Reps:
-
H. J. Meyer
Statement of Issue(s) and Justification:
Synanthropic arthropods, particularly flies and stored product insects, are characteristically associated with human activity. Although these insects are stimulated to enter the home, they are frequently associated with animal agriculture because they live and breed in the manure, spoiled feeds and other organic materials on the farm. In an effort to meet the needs of a growing human population animal agriculture has changed significantly from the small family farm to intensive and sometimes vertically integrated systems (Axtell 1999). As these farming systems increased in size and number of animals, so did quantities of manure and other insect breeding materials. Management of manure and the insects associated with manure is a challenge in poultry and livestock systems.Insects are rarely included in manure and waste management projects. Often insects are rare, for example; processing large quantities of animal waste using anaerobic lagoon digestion systems or advanced technologies like extrusion and pelleting of manure solids do not promote insect breeding. Unfortunately the associated risks from the environmental impact of lagoons to the high costs of extrusion and pelleting restrict the broad use of such waste processing systems. Other methods such as dry pit storage, deep stacking, open floor production on dry bedding, dry lots, and composting are more feasible for many growers, but these create substantial accumulations of soiled bedding, litter, manure or compost.
Under such circumstances pest management is critical before, during and after storage and subsequent to land application of litter, manure or compost. Recognized as serious economic pests, flies and litter beetles are extremely difficult to control (Harrington et al. 1999). Fly and beetle nuisance complaints often result in litigation, impacting both the farm and the farming community (Hunter 1997). Legal cases concerning nuisance flies and beetles often occur following the land application of animal waste. Rich in nitrogen (N), phosphorous (P), and potassium (K), animal manure is often applied to field soils as an organic fertilizer. Over use of organic fertilizers has resulted in state and federal regulation through animal waste management plans. The fate of N, P, and K of manure applied to field soils is a concern in concentrated production areas as there may not be enough cropland within economical hauling distance to properly use the manure. The development alternative systems that reduce manure nutrients through management, and reduce the insects associated with animal wastes will lead to better efficient utilization of these materials.
In addition to flies and other manure-breeding insects, animal wastes contain known foodborne pathogens. The CDC reports over 300,000 individuals are hospitalized annually and 76 million endure foodborne illnesses. Food related illnesses are associated with a variety of foods, particularly contaminated meat, poultry, egg products, and organic produce (CDC 1997). Escherichia coli, Campylobacter jejuni, Listeria monocytogenes, and Salmonella spp are among the leading foodborne bacterial pathogens in the US (Mead et al. 1999). The role of filth breeding insects in the dissemination and transmission of these bacteria is important to the development of pest management strategies intended to limit the spread of bacteria within the farm, and between farms and the community. Furthermore, manure management may directly affect pathogens in the manure and the safety of subsequently produced organic vegetables.
Clearly manure and pest management is essential to reducing nuisance issues in the community.
Understanding the role of these insects in the dissemination of foodborne pathogens may provide insight into the management of these bacteria in the pre-harvest interval. In this project we propose to evaluate manure management relative to filth flies, litter beetles and other insects. Manure management systems vary with commodity and region. We have selected manure management plans relative to geographic region. For example: caged-layer production in NY state relies on close-sided high-rise poultry houses with deep stacked manure, while in NC open-sided houses with wood shaving litter prevail for the meat-bird market. Each member of this multistate project will concentrate on manure management practices within their respective states. Each has investigated nuisance fly complaints and made recommendations based on solving the immediate problem. In this study we concentrate on developing a standardized method of monitoring nuisance insects and developing methods to reduce pest densities before nuisance thresholds are met. Since many nuisance complaints arise following the land application of organic fertilizers, we will also investigate the impact of manure and litter incorporation relative to soil type and condition for the management of nuisance insects. Lastly, our efforts will concentrate on the role on filth breeding insects in the harborage and dissemination of foodborne pathogens, studying the dynamics and seasonality of the relationship between insect and pathogen, and the relative importance within the farm community and the pre-harvest interval.
Stakeholder Needs: Recent surveys of poultry producers established the relative importance of filth flies and beetles associated with poultry. Flies were problematic for 22% of the NC meat bird industry (Toth et al. Unpublished data). Flies (56%) were reported as a primary pest of caged-layer production in New York poultry facilities (Harrington et al. 1999). Over 65% of NY producers felt that flies were resistant to insecticides. Fly control costs to the poultry industry were estimated at $32.4 million annually (Thomas and Skoda 1993).
North Carolina poultry producers ranked the darkling beetle their number one pest (Toth et al. Unpublished data). Darkling beetles were reported by 41% of NY poultry producers as causing economic loss (Harrington et al. 1999). Annual losses to darkling beetles have been estimated at $16 million in Virginia and $10 million in Georgia. These loss estimates are generally attributed to energy costs in beetle-damaged broiler houses, and replacement of beetle-damaged insulation. To date, no economic data exists on beetle vectored disease losses because we know little of the prevalence of disease organisms.
Management of these pests on the farm relieves livestock, poultry and employees from persistent annoyance associated with their habits and behavior. With the suburbanization of rural communities, the threat of litigation is ever present (Thomas and Skoda 1993). Recently litigants in Ohio were awarded millions of dollars in judgements against poultry producers (Miller 1997, Olejnik 2001). As a result, producers are often willing participants in applied research projects, offering use of facilities and labor. Producer interaction enables us to better develop cost-effective strategies that will work in their systems. Because of their continued involvement and assistance, producers readily adopt innovation and continue to support research and extension programs, allowing their farms to serve as applied laboratories.
Pest Species
House flies, Musca domestica, feed on a wide range of organic matter including manure and mixtures of manure, bodily excretions and decaying organic matter. The house fly is an important pest in poultry production. Dispersing distances of 2.3 to 11.8 km in 24 hours, public nuisance issues are a growing concern (Greenberg 1973, Thomas and Skoda 1993). House flies constitute a health hazard as well as an annoyance. Habitually these insects are likely to pick up disease-causing organisms and contaminate human food by crawling on the surface and depositing feces and regurgitated liquid. House flies have been implicated in the spread of over 30 bacterial and protozoan diseases.
The darkling beetle, Alphitobius diaperinus (a.k.a. litter beetle) has emerged as an important arthropod pest of poultry production (Axtell 1999). The beetle is a pest in two life-stages, mature larvae and adults. Mature larvae climb up the walls and posts of poultry facilities and chew into wood support structures and insulation weakening the structure and increasing energy consumption (Vaughn et al. 1984, Despins et al. 1987). The adult stage is a pest when manure is spread on fields. Evidence presented in litigation (Miller 1997) suggests that beetles move en masse toward artificial lights generated by residences near fields on which beetle-infested manure has been spread. The mechanism inducing such migration is poorly understood but important to solving nuisance and disease issues relative to this pest. The litter beetles is a known reservoir of wide variety of avian (and human) pathogens and parasites, including Salmonella typhimurium, Escherichia coli, tapeworms, avian leucosis virus, and turkey enterovirus (Axtell and Arends 1990, Despins et al. 1994, McAllister et al. 1994, 1996).
Poultry Production Systems
Each of the three poultry facility types principally used in poultry production in the U.S. (caged-layer, broiler, and breeder houses) has unique pest management needs. Caged-layer houses are widely used for commercial egg production and present the greatest fly and darkling beetle breeding potential. Broiler houses are wide-span structures with litter (wood shavings) covering the floor and the birds running free. Little fly breeding occurs because of the dry litter; but high populations of beetles may occur in the litter. Breeder or broiler-breeder houses are also wide-span structures with birds running free on a slat-litter floor. The outer two-thirds of the house has a slatted floor 2 to 3 feet above ground level, with a litter-covered floor in the center third of the house.
Related, Current, and Previous Work:
Results of a CRIS search indicate 373 projects involved with foodborne pathogens. The focus of these projects varied from detection methodology, and environmental contamination, to post-harvest contamination of foods. Few CRIS projects concentrated on the pre-harvest interval with an emphasis on host-pathogen interactions. Two projects include tritrophic interactions between pathogen, host and vectors; Steelman, ARK-01819 and Watson, NC-06503 include insects in the CRIS description relative to foodborne pathogens. Both are members of this multistate project. CRIS search results indicate 127 projects working on nuisance issues related to manure management focusing was on odors and environmental issues. Project MIN-17-050, Moon, concentrates on the biology and management of muscoid flies, including nuisance fly monitoring. Moon is a participant in the current project. Two terminated projects were listed in the CRIS search, Pitts, PEN-03294 (terminated in 1998) concentrated on integrated management of manure odors relative to nuisance fly issues and Sheppard, GEO-00172, (terminated in 2000) developed much of the black soldier fly biology applied in the current new-project description.National and regional priorities relate to the disposal of manure. Our project is critical because many manure management CRIS projects emphasize environmental concerns but fail to address entomological issues. The climatic, animal husbandry and environmental variation between regions influence the potential of pest insects to become a nuisance. In fact, regional variation affects the means by which the pest population may be managed. For example the proposed treatment, Black Soldier Fly manure digestion, has been proven to control house fly populations in the southern states but its application in northern regions has not been explored.
The proposed work is consistent with national and regional priorities of producing viable alternatives to traditional waste management systems, reducing pathogens in our food supply and promoting a better relationship between agriculture and an expanding non-farm public. Regional differences in poultry production require regional collaborative efforts of all the participants. Veterinary entomologists from universities, state experiment stations, ARS and CSREES are represented in this project. This coalition is positioned to address problems in poultry production systems within to their respective regions; Southeastern meat bird production, deep South and Northeastern caged layer operations or the expanding Midwestern poultry industry. Our goals are to reduce foodborne pathogens and related nuisance insect concerns relative to regional manure management options. With a growing human population within these respective regions, this project fosters a better relationship between animal agriculture and the community at large.
Likely impacts of successfully completing the work are that poultry producers will have the knowledge and tools needed to manage flies, improve biosecurity, reduce nuisance outbreaks and limit the spread of foodborne pathogens among poultry products. This will mean that producers will be able to increase bird growth rates, and egg production. These increases in productivity will exceed control costs, and increase the profit margins for these producers. Producers will be able to reduce fly and beetle numbers thereby reducing conflicts with neighbors, accurately identify fly nuisance levels should they occur and have knowledge of the risk and reduce the incidence of food-borne illness. The benefits offered through this project will provide for a better relationship between producers and residents at the rural-urban interface and provide for a safer food supply.
Conventional Manure Handling:
Deep stack manure is currently the caged-layer industry standard. In meat-bird production, free birds are placed on a 10-15 cm layer of litter (wood shavings). Depending on condition, litter may be used for successive flocks before removal and land application. Higher manure and litter moisture promotes insects.
Composting
Composting manure involves thermophilic processing and decomposition by aerobic microorganisms to produce a relatively stable organic material. High temperature significantly reduces pathogen and insect survival. There is considerable interest in composting, but few operations compost manure. Manure alone is not conducive to composting because of offensive odor and poor physical properties. Combining manure with a high-carbon bulking agent improves aeration and the physical properties of the manure.
Effects of composting on fly production potential have been examined in two recent studies. Pitts et al. (1998) tilled manure beds under caged laying hens and found that composting increased bed temperatures above 50 0C, decreased moisture content below 40%, and virtually eliminated larval house flies. Moon et al. (2001) studied the effects of composting on the subsequent nutritional value of poultry manure for larval house flies. Composting in a windrow system reduced the manure=s fly production potential by 90%.
Black Soldier Fly
The black soldier fly (BSF) is a southern native, non-pest fly that unlike the house fly, is not attracted to human habitation or foods (Furman et al. 1959). BSF reduce manure accumulations 42-56% and give 94-100% house fly control through larval competition and by repelling ovipositing house flies (Bradley and Sheppard 1984). Elimination of lesser mealworm has been noted, but not well documented. The digested residue is a friable compost-like material with about 24% less nitrogen (net loss of 60%). BSF is being investigated as a possible feedstuff for swine, poultry, and several species of fish (Sheppard and Newton 2000).
Land Application
As part of a routine manure management plan, land application is a practical means of disposing large amounts of animal wastes and an efficient use of an organic fertilizer. Unfortunately manure may contain a large number of house fly larvae and pupae, and beetles. Under S-274, Hogsette (1996) reported that fly larvae successfully complete development in sand with >1% manure solids added. Mechanical incorporation of manure is often recommended to help reduce odor and was thought to reduce the potential for a fly or beetle outbreak. Watson et al. (1998) evaluated house fly survival following the incorporation of manure into a gravel loam soil by disk, harrow and moldboard plow. Adult flies reached outbreak proportions 10 days following application, regardless of treatment, and the outbreak continued 11 days. In contrast darkling beetle survival appears to be impacted by incorporation of poultry litter into piedmont red clay soils (Watson et al. 2001). Soil type may have an impact on the successful use of this cultural practice for pest control. Other manure management methodologies may also reduce insects or pathogens before the material is land applied.
Monitoring
Since the above methods are considered industry standards for manure handling, it is imperative that we develop accurate and sensitive house fly and beetle sampling methods. Thus standardizing the evaluation methods for measuring the pest impact in agricultural and non-agricultural areas. Currently, veterinary entomologists and public health officials rely on techniques suitable on the farm. For example, Lysyk and Axtell (1986) evaluated several methods of monitoring adult fly population in poultry houses including the speck card, which has become the standard for monitoring adult flies for confined livestock and poultry. Fly densities are estimated by counting the specks on standard index cards and taking an average of several cards to establish a mean. Although adequate for determining fly densities, no information on speciation is available. Similarly, Hogsette et al. (1993) used sticky cards to monitor fly densities during a 24 hr period. The number and species of fly on the cards were counted to estimate the fly densities. Scudder grills were developed to monitor fly densities in military kitchens and mess halls. Although used routinely since 1944, the Scudder grill has not been fully validated (Scudder 1996). Mark and recapture studies conducted in Minnesota (O=Rourke 2001) evaluated baited jug traps, white sticky cylinders and a modified Scudder grill. Trap types were equally sensitive to changes in fly abundance, but the jug traps were far more efficient at catching flies when actual abundance was moderate to low. Performance of these traps and experimental alternatives remains to be evaluated in other regions of the U.S.
Litter beetles can be sampled in poultry facilities using three methods: (1) visual estimation, (2) direct manure sampling and (3) trapping. Visual sampling for litter beetles is inherently difficult and often inaccurate because of the cryptic nature of the beetle. The manure core method provides an accurate estimate of beetle populations; however, the method is labor intensive and not applicable to outdoor environments. The current standard is the tube trap (Safrit and Axtell 1984), in which corrugated cardboard is rolled and placed inside a cylinder of PVC pipe. The trap is placed on the manure or litter surface and emptied weekly, providing a measurement of changes in beetle abundance over time. Unfortunately, the traps are relatively ineffective at low to moderate beetle densities and the use of the trap outdoors is untested. One method for improving trap design to measure low densities would be to incorporate attractants into the traps.
Pathology
Food-borne pathogens originating in manure interact with insects in various ways. A potentially beneficial interaction occurs when flies of certain species reduce the pathogenic bacteria. For example, Morgan (1995) reported that medicinal maggots (Calliphoridae) reduce bacterial infections when used in wound therapy. In the case of BSF digestion of manure as a management process, potential food-borne pathogens may be reduced. Because the black soldier fly is one of our treatments, we will be examining BSF for the presence of foodborne pathogens.
The most commonly considered negative interaction occurs when adult insects vector these pathogens to humans or food animals (Greenberg 1973, Kobayashi et al. 1999). The adult house fly, and to a lesser extent, the adult darkling beetle, is of primary concern as these insects have highly developed dispersal abilities and pose the greatest risk of pathogen transmission (Despins et al. 1994, McAllister et al. 1996). Flies and beetles can be sampled to monitor the presence and prevalence of selected foodborne pathogens on the farm and in the outlying community. For this new project we will gather information on the prevalence and seasonality of foodborne pathogens in house flies and darkling beetles.
Pest Management
The management of these pests has bearing on the prevalence of these organisms in the community. IPM strategies include cultural, biological, and chemical methods to control the targeted pests. A portion of this project uses and develops cultural and biological control strategies to reduce pests. In addition to manure treatments and black soldier fly many other agents may be included, parasitoids, predators and entomopathogenic fungi (Axtell 1999).
Insecticides are important for controlling a pest outbreak, yet there are few insecticide options available to support livestock and poultry IPM. House flies are resistant to permethrin and tetrachlorvinphos and increasingly resistant to cyfluthrin (Scott et al. 2000, Kaufman et al. 2001). Four residual premise materials are registered for use against darkling beetles, tetrachlorvinphos (organophosphate), carbaryl (carbamate) lambda-cyhalothrin and cyfluthrin (both pyrethroids). Resistance is suspect in carbaryl, and two chemicals, lambda-cyhalothrin and cyfluthrin can only be used in vacant buildings, and tetrachlorvinphos is currently under FQPA review.
Objectives
- Evaluate conventional and experimental poultry manure management systems as they influence production of filth flies, litter beetles and associated foodborne pathogens.
- Evaluate novel cultural, biological and chemical strategies for pest management to minimize nuisance and health risk in the rural-urban interface.
