Reduced Pesticide Fly Control in Feedlots and Native Rangeland to Conserve Dung Beetles and Benefit Beef and Sheep Production
Beef and sheep producers in northeastern South Dakota depend largely on native rangeland. Several species of flies cause serious economic losses. An economic loss caused by horn flies, the most important pest fly of cattle in the region, was noted for the livestock in the project this year. A complete pesticide failure was also noted. Chemical control of flies with pesticides is by far the most common control method but pesticides not only can fail, but also reduce populations of beneficial insects that are essential in controlling the pest species and maintaining the rangeland ecosystem that produces the livestock feed. Invariably chemical control is harmful to some non-target species. Dung beetles are one of the most vulnerable and valuable beneficial insects in pastures.
Dung beetles were found in the project area in fair abundance. 90 percent of the dung samples collected contained dung beetles of more than one species before and after pesticide application to the beef cattle at pasture. Dung beetle friendly practices of: no chemical control for parasites within 60 days of placing cattle on pasture and no use of feed-through fly control at pasture were already in place for 2-3 years prior to the project and were helpful in controlling pest flies and parasites in 2014. Fecal samples of beef calves showed that 4 out of 5 calves had no detectable parasites in August and the 5th calf did not have a level of parasites that indicated any treatment.
Unfortunately, horn flies exceeded the economic and animal comfort threshold so chemical fly control was applied in 2014. A failure of the first pesticide used was noted and a rescue chemical application using a more eco friendly pesticide turned out to give an outstanding reduction in horn flies (98%). Only one outbreak of horn flies required treatment in each pasture.
NZI fly traps and one Walk Through Horn Fly Trap were constructed. The two types of traps have not been used on beef cattle at pasture in northeastern South Dakota before but there is a need for pest fly control that does not use chemical pesticides. Fly traps are one of the few non-chemical options. These two types of fly traps were only available through building plans, were built as part of the project and were not completed until the end of the fly season in 2014.
Adding additional ecosystem-friendly fly control practices instead of chemical controls could create a sustainable and economically effective package of practices that control pest flies without harmful levels of pesticides/vermicides and without economic losses to the producers.
Overall in 2014 construction, design and a trial of sampling methods were done so that data collection in 2015 will make a good comparison between careful use of pesticides, 2014 and reducing pesticides for fly control by using ecosystem friendly mechanical and biological control of flies.
Documentation will be extended from collecting dung beetles and keeping track of conventional pesticide fly control treatments to include the results of mechanical fly traps. Some of the livestock are sheep and cattle, some in continuous grazing, some in a rotational grazing system and some in feedlots. Dung beetle collection will continue and the best of several sampling methods tried will be used.
Identification of the dung beetles collected in 2014 should be accomplished in 2015 with the help of Extension Service or ARS entomologists.
The two mechanical methods of fly control were constructed, tested and modified so they will be ready for the start of the 2015 season so the slow but steady full season control provided by these sustainable, low input methods will have a chance to exert their effect on the fly populations of the different groups of livestock and different pastures.
Fly parasatoids may or may not be used pending the results of a survey of pest fly larvae using a protocol suggested by University of Nebraska, Lincoln’s Dr. Baxendale/ARS; but not used in 2014 because none of the project personnel could be trained in time.
Two types of fly traps were completed late in 2014. 5 NZI traps (a type of trap that has been tested on many fly species view at www.nzitrap.com) and one Walk Through Horn Fly Trap (a type of horn fly trap for cattle that can be viewed at http://extension.missouri.edu/p/MX1904C6).
The second fly season in the project will start in late April of 2015 and all practices can be used then because the fly traps are built, the rotational grazing system is in use and manure management and other farmyard practices are in use.
The two mechanical methods of fly control were constructed, tested and modified so they will be ready for the start of the 2015 season so the slow but steady full season control provided by these sustainable, low input methods will have a chance to exert their effect on the fly populations of the different groups of livestock and different pastures. The two types of traps have not been used in Grant or Roberts County and elicited interest from over a dozen people involved in raising cattle even without formal outreach.
5 NZI traps were constructed. Plans for NZI traps go to: www.nzitrap.com
1 Walk Through Horn Fly Control Trap was constructed. Plans for Walk Through Horn Fly Control Trap: request University of Missouri Extension publication G1195 or go to: http://extension.missouri.edu/p/MX1904C6 and http://extension.missouri.edu/p/G1195
Dung beetles were found to occur in great frequency in two pastures all season long.
Rotational grazing was accomplished for two beef herds.
Parasites of beef calves were found to be at a very low level, far below economic thresholds for treatment with animal drugs or pesticides, most of which are known to be harmful to dung beetles and other beneficials.
A pesticide failure occurred during treatment for horn flies and the rescue treatment with a more ecosystem friendly pesticide was very successful (98% reduction)
Livestock producers and/or landowners and others produced an interest in viewing the project results in every case.
Impacts and Contributions/Outcomes
Producer inquiries indicated that cattle and sheep producers in the area (Grant and Roberts counties South Dakota) are highly interested in fly control that uses less pesticide and if the least pesticide method is low in labor inputs they actually wish to try it on their own herds. There is also a lot of interest in dung beetles from local producers and professionals. The most common question from producers was “How do I know if I have dung beetles?” This project has already become a point of interest for a wide variety of producers and conservation minded locals, people supportive of alternative agriculture and innovations in beef production. The second most common question has been “How can I keep my dung beetles?”
Producers are requesting easy-to-read and easy-to-use guides to answer the two questions above for this part of South Dakota. Certainly this project can help satisfy the demand for information on the local ecosystem and how an ecosystem approach to fly control could work under local conditions.
Building a Walk Through Horn Fly Trap in northeast South Dakota is a first and being able to display a finished trap will give producers a chance to see that Missouri Extension Service plans are valid. Some may choose to invest in materials to build their own trap once they see the finished trap in use through this project. Several beef producers came to the shop during construction of the Walk Through Horn Fly Trap and expressed interest in seeing the finished product. Presenting a new addition to horn fly control could lead producers to a holistic approach to fly control in contrast to just one or two chemical-based practices.
A presentation on this project was given at the 2015 Farmers Forum, held in conjunction with the Northern Plains Sustainable Agriculture Society (NPSAS) Winter Conference. A video recording of this is available online through NCR-SARE’s YouTube channel at: https://youtu.be/iY8NNvMN-90?list=PLQLK9r1ZBhhFIETmMLo1dZBEVYZWXBIM1
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