2010 Annual Report
1a.Objectives (from AD-416)
Objective 1. Develop push-pull strategies for managing stable flies in agricultural systems.
Sub-objective 1A. Identify stimuli that influence fly orientation and distribution.
Sub-objective 1B. Develop a push-pull strategy utilizing identified attractants and repellents as components to manage flies.
Objective 2. Refine the application of larval control of stable flies by studying maggot distribution, manipulation of larval habitat, and geographic extent of control required.
Sub-objective 2A. Examine the causes for clumped distribution of maggots within a breeding site.
Sub-objective 2B. Examine modification of soil microflora to reduce larval stable fly populations in concentrated breeding habitats.
Sub-objective 2C. Determine effective radius of larval control required to see reduction below economic threshold on an individual property.
The purpose of this project is to develop tools for reducing the impact of stable flies on livestock production. Three entomologists are assigned to this project, each supported by a full time research technician and one or two part time students. These scientists are members of the Agroecosystem Management Research Unit (AMRU). The AMRU is a diverse research unit with soil scientists, agronomist, agricultural engineer, and microbiologists completing the staff. The scientists assigned to this project interact with co-workers having expertise in spatial statistics, soil chemistry and physics, soil microbial ecology, and chemical synthesis and formulation to accomplish the mission of the unit.
1b.Approach (from AD-416)
Methodologies to achieve the objectives:.
1)Examine the morphology and structure of sensory organs of stable fly adults and larvae..
2)Electrophysiological techniques will be used to identify attractant constituents associated with host animals (breath and skin emissions, etc.) and oviposition substrates (livestock animal manures and decomposing organic matter such as silage, rotting hay, and grass/alfalfa clippings).
3)Identify and evaluate novel repellents on stable fly populations. .
4) Use visual and landscape features to develop a spatiotemporal model of stable fly dispersion that will describe and predict habitat use and suitability for larvae and adults..
5)Develop formulations of identified attractants and repellants for field application. .
6)Reduce stable fly populations in confined and pastured cattle with Push-Pull strategy..
7) Take a holistic approach to reduce the development of immature stable flies by examining the biological, chemical, and physical characteristics of larval developmental sites and develop tools to modify these sites to render them unsuitable for stable fly development. Though this research will be directed at a better understanding of the stable fly habitat, other filth flies developing in similar habitats will be examined. .
8)The limits of chemical and physical properties on survival of both stable flies and house flies will be studied in the laboratory. .
9)Patterns of stable fly and house fly larval dispersal in relation to physical and chemical factors will be studied in the laboratory..
9) Mark release recapture studies will be performed in the field to study stable fly larval dispersal. 10) Antibiotics and food preservatives will be tested in the laboratory and then the field to determine their effect on stable fly survival. 11) Self marking technique will be used at stable fly larval development sites to study the dispersal distances from these sites.
Morphology and structure of sensory organs. We have completed the study of stable fly's olfactory sensilla by SEM, and found three types of olfactory sensillar hairs that are used by stable fly to locate hosts and oviposition sites. A 3-D map was constructed to show their distribution on the 3rd antennal segment. Stable fly antennae responding strongly to several cattle associated host animal and environmental volatiles. Preliminary behavioral tests both in lab and field show that these compounds enhance trap catches.
Repellants. We found catnip essential oil and its active compounds, nepetalactones, to be strong spatial repellants for stable flies. Catnip oil reduces feeding by more than 95% and deters egg laying on a treated surface by more than 96%. A wax-pellet formulation containing 10% catnip oil was developed and tested on stable fly resting areas in a beef cattle feedlot. The formulation repelled stable flies for more than 4 hours.
Larval developmental sites. A survey of the spatial variability of the substrate in a winter hay feeding site was completed. Substrate electric conductivity was mapped and then core samples were taken from representative areas for determination of dissolved carbon, pH, inorganic nitrogen, water content, ash content, and bulk density. Emergence traps were then used to correlate physical properties of the substrate with the distribution of emerging flies. Data analysis is in progress.
Adult dispersal. Three mark-release-recapture studies were conducted to examine the effects of age and nutritional status on stable fly dispersal. Data analysis is in progress.
Development of an economic model to estimate the impact of stable flies. Stable flies are known to be a major livestock pest but there are no current estimates of their economic impact. A dynamic and explicit model was developed by ARS scientists in Lincoln, NE to estimate the economic impact of stable flies on the US cattle industry. Results indicate production losses of $872 million to the dairy industry, $114 million to cow / calf operations, $1,262 million to pastured stocker cattle, and $197 million to feeder cattle for a total impact of nearly $2.5 billion in 2008. This model provides the data needed for producers to include cost-benefit analyses when making decisions concerning the cultural changes needed to reduce stable fly populations on a regional scale.
Evaluation of Catnip as a repellent for stable fly. Stable flies are a major livestock pest that costs the industry millions of dollars annually. Currently the only stable fly repellents commercially available are based on pyrethroids which are ineffective because stable flies carry a gene for pyrethrin resistance. ARS scientists in Lincoln, NE determined that Catnip effectively repels stable flies in bioassays and are evaluating its effectiveness in feedlot environments. The catnip based repellent represents the first new spatial repellent developed for stable flies in the last 30+ years. Commercialization of catnip oil as a stable fly repellant may provide short-term reduction of stable fly biting activity until area-wide integrated pest management measures can be implemented.
Taylor, D.B., Moon, R.D., Campbell, J.B., Berkebile, D.R., Scholl, P.J., Broce, A.B., Hogsette, Jr, J.A. 2010. Dispersal of stable flies (Diptera: Muscidae) from larval development sites in a Nebraska landscape. Environmental Entomology. 39(4):1101-1110.