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United States Department of Agriculture

Agricultural Research Service

Research Project: SUSTAINABLE PEST MANAGEMENT SYSTEMS FOR BLOOD-FEEDING FLIES AFFECTING LIVESTOCK

Location: Tick and Biting Fly Research

2005 Annual Report


1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter?
The livestock industry provides approximately 50% of the annual agricultural income of the U.S. Potential economic losses, as a result of uncontrolled parasitism by arthropod pests, are estimated at $2.2 billion annually. Potential losses to the beef cattle industry due to the stable fly and the horn fly are estimated at $432 million and $876 million annually, respectively. Both the stable fly and the horn fly are important deterrents to cost-effective beef cattle production in an industry with minimal margins of profit. Historically, the stable fly has been primarily a pest of dairy cattle and beef cattle confined in feedlots, but problems with the stable fly on pastured cattle are increasing. No practical methods exist for the control of stable flies on pastured cattle. The biology and behavior of stable flies requires the development of unique methods for treating cattle with control agents, or for controlling immature flies at breeding sites, or adults before they feed on cattle. In contrast, a variety of insecticide-based methods are available to producers for control of horn flies, but those methods are hampered by the widespread resistance of these parasites to pyrethroid insecticides and, to a lesser degree, organophosphorous compounds. New technology and treatment strategies are needed to: .
1)minimize the quantity of insecticide needed to control both fly species and reduce the rate of selection for pesticide resistance;.
2)reduce or eliminate reliance on conventional, non-specific insecticides;.
3)provide novel physical, biological, or chemical control options; and.
4)provide complementary combinations of control methods that can be used in integrated pest management strategies for biting fly control. Tools to guide producers in the development and implementation of management strategies suited to their production goals and circumstances are also needed. It is important that we develop sustainable management technologies for livestock pests in order to provide an abundant, reliable, economical, and safe supply of beef to the dinner table of the consumer.

Currently, insecticides are the primary and, in most cases, the sole means of control. New and innovative control technologies are needed to reduce or eliminate our reliance on pesticides and to preserve the utility of existing chemicals by delaying the onset of resistance to these chemicals. The overall objectives of this research are to discover, develop, and deploy effective, environmentally safe tools and sustainable strategies for the integrated management of livestock pests. To accomplish our overall objective, we have three specific objectives: .
1)Develop and improve methods of chemical control of horn flies and stable flies;.
2)Develop alternatives to classical chemical control of horn flies and stable flies; and.
3)Develop and evaluate control strategies to provide sustainable pest management practices.

This research addresses goals within the components of NP 104 of Veterinary, Medical and Urban Entomology. Specific goals addressed are: 1.1.2 Determine the dispersal patterns, breeding habits and host attractions of horn flies, house flies and stable flies that may be useful in devising control strategies; 3.1.4 Identify food animal genotypes naturally resistant to blood feeding arthropods, characterize the mechanisms, and isolate the responsible genes; 4.1.1 Develop the capacity to test existing compounds for toxicity against Diptera and ticks that transmit disease; 4.1.2 Develop and test novel means of applying pesticides and repellents that are more efficient, inexpensive and selective, including the development of toxic baits, methods to bond agents to material, and area repellents; 4.2.1 Identify, isolate, cultivate, characterize, and test natural pathogens and predators of vectors and pests. Develop methods to enhance the specificity and lethality of control agents; and, 4.3.1 Integrate biological and chemical suppression techniques with knowledge of behavior and dispersion to develop and test large area prevention and control strategies.


2.List the milestones (indicators of progress) from your Project Plan.
Year 1 (2005)

Develop an extended-delivery doramectin injectable gel formulation Evaluate new classes of chemicals for efficacy against horn flies Evaluate strains of entomopathogenic fungi against horn flies Conduct horn fly carrying capacity phenotyping of annual calves Develop techniques for thrombostasin purification Optimize recalcification time determinations Construct pedigree of annual phenotyped calves Conduct feed through studies of azadirachtin for control of horn flies and stable flies Factors affecting entrance into and emergence from horn fly diapause Complete phase 1 of horn fly trap Develop horn fly management strategies

Year 2 (2006)

Optimize an extended-delivery doramectin injectable gel formulation Optimize release rate from an avermectin ruminal bolus New methods of control of larval stable flies Evaluate new classes of chemicals for horn fly and stable fly control Improve formulations for delivery of entomopathogenic fungi against horn flies Conduct horn fly carrying capacity phenotyping of annual calves Construct pedigree of annual phenotyped calves Conduct annual thrombostasin variant survey Conduct annual bovine prothrombin survey Develop ruminal bolus of azadirachtin for control of horn flies and stable flies Factors affecting entrance into and emergence from horn fly diapause Complete phase 2 of horn fly trap Develop horn fly management strategies

Year 3 (2007)

Develop ruminal bolus with new macrocyclic lactones New methods of control of larval stable flies Evaluate new classes of chemicals for horn fly and stable fly control Field test improved formulations for delivery of fungi against horn flies Conduct horn fly carrying capacity phenotyping of annual calves Construct pedigree of annual phenotyped calves Conduct annual thrombostasin variant survey Conduct annual bovine prothrombin survey Optimize ruminal bolus of azadirachtin for control of horn flies and stable flies Factors affecting entrance into and emergence from horn fly diapause Complete phase 3 of horn fly trap Develop horn fly management strategies

Year 4 (2008)

Develop ruminal bolus with new macrocyclic lactones New methods of control of larval stable flies Evaluate new classes of chemicals for horn fly and stable fly control Improve formulations for delivery of entomopathogenic fungi against horn flies Conduct horn fly carrying capacity phenotyping of annual calves Construct pedigree of annual phenotyped calves Conduct annual thrombostasin variant survey Conduct annual bovine prothrombin survey Optimize ruminal bolus of azadirachtin for control of horn flies and stable flies Factors affecting entrance into and emergence from horn fly diapause Complete the development of horn fly trap Develop horn fly management strategies

Year 5 (2009)

Develop ruminal bolus with new macrocyclic lactones New methods of control of larval stable flies Evaluate new classes of chemicals for horn fly and stable fly control Improve formulations for delivery of entomopathogenic fungi against horn flies Conduct horn fly carrying capacity phenotyping of annual calves Construct pedigree of annual phenotyped calves Conduct annual thrombostasin variant survey Conduct annual bovine prothrombin survey Optimize ruminal bolus of azadirachtin for control of horn flies and stable flies Factors affecting entrance into and emergence from horn fly diapause Complete the development of horn fly trap Develop horn fly management strategies


4a.What was the single most significant accomplishment this past year?
Evaluation of New Classes of Chemicals for Efficacy Against Horn Flies. In a continuing effort to find alternatives to conventional pesticides, research at the Knipling-Bushland U.S. Livestock Insects Research Laboratory is exploring the use of natural products for control of horn flies and stable flies. We have shown that azadirachtin, an extract of neem seed with IGR-like activity, is capable of inhibiting production of adult horn flies and stable flies in manure, but is not practical because of its degradation. To avoid the rapid degradation of the active agent, new more stable formulations of azadirachtin have been developed as a feed premix and were fed to cattle as a feed-additive at levels of 1-6 mg/kg/body weight. Dosages of approximately 2.5 mg/kg body weight/day provided 50% control of immature stages of the horn fly in the manure of treated cattle. Approximately 6 mg/kg body weight/day was required to provide 50% control of stable flies and house flies in the manure of cattle. The ability to incorporate this natural extract into feed stock of cattle could enable fly control. A commercial concern is using this data to seek FDA registration of the formulations as feed-additives for use as a larvicide against these economically important pests of cattle.


4b.List other significant accomplishments, if any.
Conduct Thrombostasin Variant Survey. Thrombostasin (TS) was isolated and characterized from salivary glands of the horn fly. TS enables successful feeding of the horn fly by preventing or slowing blood coagulation. At the Knipling-Bushland U.S. Livestock Insects Research Laboratory, we evaluated the isoform (variant) frequency of thrombostasin, an anti-thrombin of the horn fly in a substantial collection of flies obtained from select individuals within a herd that had been phenotyped for susceptibility to horn fly infestation. The distribution of each isoform among the phenotyped calves was analyzed in an effort to provide information regarding TS variants associated with phenotypes, i.e., high or low fly-carrier. The TS frequency data collected suggests that there is a significant difference between the TS variants of flies from high-carrier calves and flies from low-carrier calves. In addition, two high frequency genotypes from the surveyed population were essentially absent from those reported previously in the literature. This intriguing result has prompted us to examine the biochemical properties of the variants represented by these genotypes. The discovery of an association between the horn fly distribution within a herd and specific isoforms of the anticoagulant molecule should provide a genetic marker for breeding and selecting a low fly carrying phenotype of cattle.


4c.List any significant activities that support special target populations.
None


4d.Progress report.
In an on-going project at the Knipling-Bushland U.S. Livestock Insects Research Laboratory, Kerrville, TX, we are accumulating a significant genomic database on cattle that have been phenotyped for horn fly carrying capacity. The database should provide a fruitful biological asset for gene mining and subsequent publication. Currently, the genomic DNA of 192 phenotyped individuals has been added to the database (76 cows and 116 calves), with a goal of 300 individuals. The database represents a significant resource, as it consists of biological material that can be utilized in studies regarding host resistance to ectoparasites. The selection for natural resistance to livestock pests, such as horn flies and ticks, may provide an effective tool for management of these pests. Our studies characterized the distribution of horn flies on cattle within a herd. Data from phenotyping of herd cows and calves enabled determination of low and high carrying animals, and revealed that the percentage of the population individuals carry varies little from observation to observation. This technique of identification and selection of low and high carriers can lead to useful protocols for breeding to improve natural resistance to horn flies, as it has been used against lice.


5.Describe the major accomplishments over the life of the project, including their predicted or actual impact.
Use of entomopathogenic fungi for the control of horn flies. Due to resistance problems and growing concerns over the environmental impact of synthetic insecticides, a need for more natural, alternative types of control for biting flies on cattle has arisen. Entomopathogenic fungi are naturally occurring fungi that infect a specific, limited group of host insects without negatively affecting the environment. During the past year, three strains of entomopathogenic fungi, Beauveria bassiana (strain GHA), Metarhizium anisopliae (strain ESCI), and Paecilomyces fumosoroseus, were tested in the laboratory for control efficacy against horn flies. In studies designed to simulate on animal control, treatment in the lab with B. bassiana resulted in greater than 90% mortality of horn flies within seven days. M. anisopliae and P. fumosoroseus were not as effective. Preliminary evaluations of all three strains on cattle in the field also showed that B. bassiana may be an effective horn fly control treatment when used in a dust or spray on application. This research directly supports ARS Strategi Plan Goal 3: Enhance Protection and Safety of the Nation's Agriculture and Food Supply, and Performance Measure 3.2.1: Provide scientific information to protect animals from pests, infectious diseases, and other disease-causing entities that affect animal and human health. This accomplishment addresses NP 104 Strategic Plan Goal 3 and Performance Measure 3.2.1 of the ARS Stratetic Plan.

Evaluate new classes of chemicals for efficacy against horn flies. Because chemicals are currently the primary means of horn fly control, it is necessary that we maintain an arsenal of effective chemicals for use by the producer. New neonictinoids were evaluated both using in vitro and in vivo bioassays against the horn fly. These were compared for relative efficacy against diazinon and fipronil. Results were reported to the sponsoring company with suggestions for formulation improvements. Neonicotinoids could be useful tools in combating resistance to pyrethroids and organophosphates. This research directly supports ARS Strategic Plan Goal 3: Enhance Protection and Safety of the Nation's Agriculture and Food Supply, and Performance Measure 3.2.1: Provide scientific information to protect animals from pests, infectious diseases, and other disease-causing entities that affect animal and human health.

Horn Fly carrying capacity phenotyping of annual calves. This objective will continue throughout the life of the project; thus, it has no completion date or a publication planned. The sole purpose of the objective is to accumulate a significant genomic database on cattle that have been phenotyped for horn fly carrying capacity. The database should provide a fruitful biological asset for gene mining and subsequent publication. Currently, the genomic DNA of 192 phenotyped individuals has been added to the database (76 cows and 116 calves), with a goal of 300 individuals. The database represents a significant resource, as it consists of biological material that can be utilized in studies regarding host resistance to ectoparasites. This research directly supports ARS Stragetic Plan Goal 3: Enhance Protection and Safety of the Nation's Agriculture and Food Supply, and Performance Measure 3.2.1: Provide scientific information to protect animals from pests, infectious diseases, and other disease-causing entities that affect animal and human health.


6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products?
Technology developed as a result of this research is shared with other scientists by presentations at meetings and publication in scientific journals. We are in constant contact with industry to encourage development of the technology for benefit of producers. We have signed agreements with several industrial entities to promote the research and development.


7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below).
Temeyer, K.B., Lohmeyer, K.H., Chen, A.C., Foil, L.D. 2005. Recent Progress in Understanding Organophosphate Resistance in Horn Flies and Cattle Fever Ticks. 49th Annual Meeting of the Livestock Insects Workers’ Conference, June 19-21, 2005, Bozeman, Montana.

Miller, J.A., Pound, J.M. 2005. Research at the Knipling-Bushland U.S. Livestock Research Laboratory in support of the War Fighter Intiative. Armed Forces Pest Management Board Annual Review, March 1-3, 2005, Gainesville, Florida.

Klavons, J.A., Miller, J.A., Pound, J.M., Lohmeyer, K.H. 2005. A Sustained-Release, Bio-absorbable, Injectable Gel Formulation for Delivery of Doramectin to Cattle for Control of Ticks and Biting Flies. American Chemical Society, 229th National Meeting, March 12-17, 2005, San Diego, California.


Last Modified: 8/19/2014
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