Progress 10/01/07 to 09/30/12
Outputs
OUTPUTS: We concluded a 2-year study of ear tags on horn fly control and cattle productivity in west central Nebraska rangeland. Effects on face fly and stable fly numbers were also made. Seasonal weight gain and pregnancy rates were measured to assess cattle health and well-being. Testing was done at two University of Nebraska-Lincoln locations: the West Central Research Extension Center (WCREC, North Platte, NE) and the Barta Brothers Ranch (Rose, NE). Treatments were applications made to groups of heifers or cow/calf pairs of Corathon ear tags or control (no fly management) by pasture. Horn flies, face flies, and stable flies per animal were enumerated using standard techniques based on digital photography or visual counts. Fly sampling was done weekly beginning in June of 2011 and 2012 for the fly season; 15 and 12 weeks in 2011 and 2012. At the WCREC location, heifer pregnancy cycles were synchronized using standard methods and the heifers were then subsequently artificially inseminated. All fly count data was log transformed and analysis performed on this variable. Repeated Measures and Least Square Means in GLIMMIX (SAS Institute 9.2) were used to determine effects of treatment and fly population numbers. At the Barta ranch, covariate analysis on beginning calf weight was used. At the WCREC location, the Corathon tag treatment provided good horn fly control until weeks 12 (year 1) and 10 (year 2). Overall numbers of horn flies between treated and control heifers did not differ significantly. At the Barta ranch, the ear tag treatment began to decline (more than 100 flies per treated animal) after week 9. Overall, horn fly numbers on treated cows averaged 118 flies compared to 491 flies on the control cows and were significantly different. Face fly numbers at WCREC did not differ significantly either year or overall. In year 1, the occurrence of pink-eye was a problem, especially with heifers with Corathon tags and the bacterium Moraxella bovoculi was detected from two animals. No incidences of pink-eye were observed during year 2. Face flies were not observed in the study at the Barta ranch. Stable fly numbers were very low or not observed at both testing locations. At WCREC, the average daily gain (ADG) during the first eight weeks of the study was 1.8 lb per heifer for the control group compared to 2.1 lb for the Corathon tagged group. However, overall, there were no significant differences in ADG or final body weight between the control and the Corathon tagged groups. Between treatments groups, heifer pregnancy rates were not significantly different. Final calf weight at the Barta ranch differed significantly between treatments and the final weight gain of calves treated with Corathon tags was significantly greater (11.8 lbs) than calves from the control group. PARTICIPANTS: PIs: Gary Brewer, Professor and Head, Dept. of Entomology, University of Nebraska-Lincoln and David Boxler, Assistant Extension Educator, West Central Research & Extension Center, University of Nebraska- Lincoln. Collaborator(s) - Rick Funston (UNL Extension Specialist), Larry Hawkins (Bayer Animal Health), Dennis Bauer (UNL Extension Educator), Clay Kucera (Nebraska cattle rancher). Partner Organization(s) - Bayer Animal Health. TARGET AUDIENCES: Nebraska ranchers, veterinarians, and livestock managers, especially in central and west Nebraska. Other research and extension specialists working in livestock entomology. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Ear tags are designed to manage horn flies by making season long, low-dose applications of an insecticide to the shoulders and backs of cattle. However, ear tags based on some chemical classes have performed poorly because of known or suspected insecticide resistance the in the affected fly populations. In a multiple year study, we tested the efficacy of Corathon ear tags (Bayer Animal Health) with 50% active ingredients (organophosphates: 35% diazinon and 15% coumaphos) to manage horn flies in two central Nebraska pasture systems. We found that the ear tags provided good horn fly control for 9, 10 or 12 weeks depending on year and location. We also evaluated the efficacy of the ear tags to manage face and sable flies. Populations of face and stable flies were very low or not observed and no detected reductions in numbers of these flies were observed. We also assessed animal weight gains, pregnancy rates, and incidence of pink eye. No difference was observed in final weights or average daily gain between treated and control heifers in a two-year study. Between treatments groups, incidence of pink-eye or heifer pregnancy rates did not differ. However, weaning weights of treated calves exceeded control calves by 11.8 lbs in a replicated 1-year study.
Publications
- Tangtrakulwanich, K. 2012. Sensory morphology and chemical ecology of the stable fly, Stomoxys calcitrans: host-seeking and ovipositional selection. PhD dissertation, pp 116. Univ. of Nebraska-Lincoln.
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Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: Biting and nuisance fly control on Nebraska pasture cattle is becoming increasingly difficult because of insecticide resistance and product unavailability due to loss and registrations and voluntary withdrawals. In 2011, we worked on alternative and conventional fly control technologies. We tested the effectiveness of catnip (Nepeta cataria L.) oil and its constituent compounds, nepetalactones, as stable fly repellents and toxicants. Nepetalactones, compared to other plant essential oils, demonstrated strong repellency against stable flies. DEET, the most commonly used mosquito repellent, is relatively ineffective against stable flies. Nepetalactones were also strong oviposition repellents reducing gravid stable fly oviposition by 98%. In fumigant bioassays, catnip oil (20 mg dosage) showed the highest toxicity against stable flies, the shortest knock-down time (∼7 min), and the quickest lethal time (∼19 min). No differences in knock-down and lethal times were found among catnip oil and its two active ingredient compounds. Mortality was similar whether testing was done in fumigant jars or a modified K&D system. Topical application of catnip oil applied to stable flies showed lethality at 12.5 μg/fly; a 50 μg/fly dose resulted in 100% mortality. Our results show that catnip oil is repellent to stable fly feeding and oviposition behaviors and has both contact and fumigant toxicity against the stable fly and thus has the potential as an alternative for stable fly control. To better understand the physiology of stable fly behavioral responses to catnip oil, we measured electroantennogram results of stable fly antennae to host-associated compounds. We also examined the antennal morphology of adults using scanning electron microscopy techniques. Electroantennogram results indicated significant antennal responses to host-associated compounds and emphasized the importance of sensilla on the antennae in host orientation. Four major sensillum types, (a) basiconic sensilla; (b) trichoid sensilla with three subtypes; (c) clavate sensilla, and (d) coeloconic sensilla, were found on the antennae. Except for medium-sized trichoid sensilla, no significant differences between male and female flies in abundance of these sensillum types were observed. The surface of basiconic and clavate sensilla had distinctive pore structures suggesting olfactory functions. The trichoid and coeloconic sensilla were without pore structures and are probably mechano-receptors. Maps of the distributions of the sensillum types located on the funicle of the fly antenna were made. Conventional management of horn flies on pasture cattle depends on insecticide impregnated ear tags. We initiated a 3-year study of ear tags on horn fly control and cattle productivity in west central Nebraska rangeland. Impacts on horn fly, face fly and stable fly numbers on treated cattle will be made. Seasonal weight gain and pregnancy rates will also be measured to assess cattle health and well being. PARTICIPANTS: Gary Brewer, Professor and Head, Roberto Cortinas, Assistant Professor, Blair Siegfried, Professor, and Khanobporn Tangtrakulwanich, PhD student, Dept. of Entomology, University of Nebraska-Lincoln. David Boxler, Assistant Extension Educator, West Central Research & Extension Center, University of Nebraska-Lincoln. Junwei (Jerry) Zhu, USDA-ARS, and Associate Adjunct Professor, Dept. of Entomology, University of Nebraska-Lincoln. Justin Talley, Assistant Professor, Dept. of Entomology and Plant Pathology, Oklahoma State University. Bill Reifenrath, Stratacor Inc., Richmond, California. TARGET AUDIENCES: Nebraska ranchers, veterinarians, and livestock managers, especially in central and west Nebraska. Other research and extension specialists working in livestock entomology. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Our findings show that plant essential oils, particularly catnip oil, have potential to manage biting and nuisance flies on cattle in Nebraska pasture conditions. Repellents provide human protection against mosquitoes and other biting flies and arthropods but are not used to protect range cattle. Catnip oil is generally regarded as safe, is repellent to flies on cattle, and has potential to reduce cattle annoyance and defensive behaviors. In addition, as an oviposition repellent, catnip oil may be effective in limiting production of adult flies. If combined with attractants combined with an insecticide in a push-pull technology, catnip oil can move flies away from cattle and increase fly mortality. Conventional fly management relies heavily on ear tags to protect range cattle. Our studies with slow release ear tags will provide efficacy data on new formulations in reducing fly numbers and in preserving cattle health and productivity that will be extended to ranchers.
Publications
- Tangtrakulwanich, K., H. Chen, F. Baxendale, G. Brewer, and J. J. Zhu. 2011. Characterization of olfactory sensilla of Stomoxys calcitrans and electrophysiological responses to odorant compounds associated with hosts and oviposition media. Med. Vet. Entomol. 25 (3): 327-336.
- Zhu, J., A. Y. Li, S. Pritchard, K. Tangtrakulwanich, F. P. Baxendale, and G. Brewer. 2011. Contact and fumigant toxicity of a botanical-based feeding deterrent of the stable fly, Stomoxys calcitrans (Diptera: Muscidae). J. Agric. Food Chem. 59 (18): 10394-10400.
- Zhu, J., D. Berkebile, C. Dunlap, A. Zhang, B. Aijun, R. Behle, D. Boxler, K. Tangtrakulwanich, G. Brewer, F. Baxendale. 2011. Nepetalactones, a stable fly feeding and ovipositional repellent from the essential oil of Nepeta Cataria. Med. Vet. Entomol. DOI: 10.1111/j.1365-2915.2011.00946.x
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Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: Results on the efficacy and residual activity of insecticide treated target traps for stable fly control; and the results of mist blower application and evaluations of several new ear tags for efficacy on management of horn and stable flies were reported at the annual meeting of the multistate research project, S-1030, "Flies Impacting Livestock, Poultry and Food Safety". Information on best practices for managing biting and nuisance flies on cattle, with an emphasis on pastured cattle in central and western Nebraska, was disseminated to ranchers, veterinarians, and consultants in Nebraska through meetings and direct phone and email contacts. At the August 2010, Gudmundsen field day a presentation was made on horn fly and stable fly numbers, impacts on cattle productivity, and best management practices. An update on flies of veterinary importance and their management was made at the fall extension entomology workshop at the University of Nebraska. Grants were submitted to NIH, USDA, and the Gates foundation. PARTICIPANTS: Gary Brewer, Professor and Head, Roberto Cortinas, Assistant Professor, Blair Siegfried, Professor, and Khanobporn Tangtrakulwanich, PhD student, Dept. of Entomology, University of Nebraska-Lincoln. David Boxler, Assistant Extension Educator, West Central Research & Extension Center, University of Nebraska-Lincoln. Junwei (Jerry) Zhu, USDA-ARS, and Associate Adjunct Professor, Dept. of Entomology, University of Nebraska-Lincoln. Justin Talley, Assistant Professor, Dept. of Entomology and Plant Pathology, Oklahoma State University. Bill Reifenrath, Stratacor Inc., Richmond, California. TARGET AUDIENCES: Nebraska ranchers, veterinarians, and livestock managers, especially in central and west Nebraska. Other research and extension specialists working in livestock entomology. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
A three year study to evaluate the efficacy of a mist blower sprayer for the reduction of horn flies, Haematobia irritans, and stable flies, Stomoxys calcitrans (Diptera: Muscidae), on pastured cattle in central Nebraska was completed during the fall of 2010. The study utilized cow/calf pairs in herds ranging in size from 15 to 48 pairs. Approximately weekly during fly season, flies per cow were sampled from a randomly selected subset of cows per herd. New subsets were selected each sampling date and standard sampling protocols were used. An untreated group of cow/calf pairs served as a comparison. Insecticide treatments were made weekly or as needed and alternated during the season between application of a synthetic pyrethroid or a spinosad. Treatments were made using a Model SD-RM20-H855 mist blower with rates ranging from 2.0 to 4.5 gallons per herd, depending on herd size. Treatment reduced horn fly numbers 58%, 56%, and 41% in 2008, 2009, and 2010. Over the 3 year period, horn fly numbers averaged 159 per cow on sprayed groups versus 339 flies per cow on untreated groups, a 53% reduction. Stable flies per cow were reduced 70%, 86%, 61% in the three years respectively. Overall, there was an average of 2.4 stable flies per treated cow versus 8.5 per untreated cow; a 72% reduction in stable fly numbers. Because field monitoring studies indicated olfaction is important in host location, we examined the antennal olfactory sensilla morphology of stable fly adults using advanced scanning electron microscopic techniques. Four major types of sensilla were described: 1) sensilla basiconica, 2) sensilla trichodea, 3) sensilla clavate, and 4) sensilla coeloconica. No significant differences in abundance (total numbers) of sensilla were observed among the sensilla types between male and female stable flies, except medium-sized trichoid sensilla. Distinctive pore structures on the surface of basiconica and clavete sensilla suggest they have a chemoreceptory function and are olfactory sensilla. No wall pores were found in trichoid and coeloconic sensilla suggesting these two types of sensilla may function as mechano-receptors. However, coeloconic sensilla have been described as thermo-hygroreceptors from other fly species. Details in distributions of different sensilla types located on the funiculus of the stable fly antennae were mapped. Electroantennogram results indicated significant antennal responses to host associated compounds. The importance of stable fly olfaction relative to host and host environment seeking are also discussed. This research provides valuable new information that will enhance future developments in integrated stable fly management.
Publications
- Tangtrakulwanich, K., H. Chen, F. Baxendale, G. Brewer, J. Zhu. 2010. Characterization of olfactory sensilla of Stomoxys calcitrans and electrophysiological responses to odorant compounds associated with their host and oviposition media. J. Med. Entomol. (in press).
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: We tested chemical delivery and attract and kill methods to manage stable flies, Stomoxys calcitrans, and horn flies, Haematobia irritans, as part of an integrated program for rangeland cattle production. As part of a multi-year study, pastured cattle were treated with registered insecticides using a mist blower applicator. Fly management was integrated into normal cattle management operations. The mist blower was placed in the back of a pickup truck and distillers' grain was used to bring the cattle to a watering station. The mist blower drifts a gentle spray over the cattle and after initial conditioning the cattle water normally. Spray stream technology startles the cattle and disrupts normal behavior so that some animals will not water. In 2007 and 2008 cattle were treated weekly. Fly irritation was minimal, cattle did not bunch, and weight gain was normal. Treated herds had lower horn and stable fly populations compared to non-treated herds. However, 2009 was wetter and more favorable for fly development and survival. It was necessary to make twice weekly applications to reduce fly numbers to acceptable levels. While the technology is a promising guides to treatment frequency need to be developed and the economics determined. Additional insecticides are needed to minimize the development of insecticide resistance. Besides on-animal treatment, attract and kill technologies were tested. LSU traps consisting of blue, insecticide impregnated cloth have been effective in some situations and areas of the country. However, in central Nebraska effective fly control has not been achieved even though the traps maintain season-long potency. End of season bioassays in 2008 and 2009 show fly mortally at a 15 second exposure was greater than 90%. While trap potency remains excellent over the season not enough flies are attracted to the traps compared to the cattle themselves to effectively reduce fly populations. However, because of the ease of use, low cost, and very small amounts of insecticide used trap technology needs further testing. Alternative trap placement to increase the portion of the fly population exposed is needed. PARTICIPANTS: Individuals working on the project include Gary Brewer, project supervisor, and Dave Boxler, Research Technologist. In collaboration with an industry partner NIH and Gates proposals were submitted. TARGET AUDIENCES: The primary target audience for this project is cattle ranchers in central and western Nebraska and other Great Plains states. Other audiences are cattle producers in eastern Nebraska and similar habitats. Trap technology and proposed biopesticide testing have human health implications. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Multi-year testing of mist blower technology to manage biting and irritating flies on range cattle in central Nebraska is effective in preventing fly defensive behavior and maintaining cattle weight gain. Guidelines for application frequency and economic thresholds need development. Insecticide treated cloth (LSU traps) remains highly effective in killing flies even after season-long exposure to central Nebraska conditions. More effective trap placement is needed to increase the portion of the fly population encountering the treated trap cloth and receiving a lethal dose. As part of an effort to develop and test novel insecticides to manage fly populations an NIH proposal was submitted in partnership with industry.
Publications
- No publications reported this period
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: We tested chemical delivery and attract and kill methods to manage stable flies, Stomoxys calcitrans, as part of an Integrated Pest Management program for rangeland production. A second year of testing of a mist blower application technique as part of an overall cattle management plan appears promising. The mist blower was used to make weekly insecticide application to range cattle at watering stations. Normally, the cattle are dispersed throughout the pasture and only when they come to water stations are they concentrated sufficiently to allow treatment. To help acclimatize the cattle to the sound and feel of the treatment they were provided with distillers' grain just prior to treatment. Treated cattle become accustomed to the mist blower treatment and experience lower stable fly populations, usually below the economic threshold, compared to groups of control cattle. Treated cattle were observed to disperse and feed throughout the day instead of bunching in pasture corners in fly-defensive behavior. The mist blower application also shows promise for control of horn flies. Gower interest in using mist blowers to improve cattle weight gain and to minimize pasture damage resulting from bunched cattle is increasing. Mist blower technology is being presented at grower meetings. However, it is being emphasized that the results, while promising, are limited. LSU traps consisting of blue, insecticide impregnated cloth were tested in Nebraska range settings as a way to attract and kill stable flies on cattle. Traps were sited near watering sources that were visited by cattle twice a day. While the cattle were watering, flies were observed landing on the treated cloth. At the end of the season, field-weathered, insecticide impregnated cloth was removed from a trap to test in bioassay for residual activity against stable flies. Larvae were collected from habitats in central and western Nebraska as part of a study of genetic variability of North American stable flies. PARTICIPANTS: Individuals working on the project include Gary Brewer, project supervisor, and Dave Boxler, Research Technologist. TARGET AUDIENCES: The primary target audience for this project is cattle ranchers in central and western Nebraska and other Great Plains states. Other audiences are cattle producers in eastern Nebraska and similar habitats. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The second year of testing showed that mist blower applications can reduce on-cattle populations of stable flies. However, more work needs to be done to verify the efficacy of mist blower applications, to determine when treatment should start and when it can be stopped, and to determine effective insecticide rotations. Flies exposed to season-long, weathered cloth taken from a LSU trap in laboratory bioassay for 30 and 60 seconds experienced high mortality. This suggests that flies landing on trap cloths in the field throughout the season had the potential for receiving a lethal insecticide dose. However, little reduction in on-cattle fly numbers was observed in the field. This suggests one or more of the following: few flies land on the traps, flies do not remain on the traps for a sufficient time period to become intoxicated, not enough traps were used to reduce on-cattle fly numbers, or that cattle may be recruiting new flies when away from the traps that replace files killed by landing on the traps.
Publications
- No publications reported this period
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