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ISSUE 8  JUNE 24, 1999


North-Central ND

Fly Control for Pastured Cattle

    There are several species of fly that annoy cattle in the pasture — horn flies, face flies, stable flies, horse flies, deer flies, black flies and mosquitoes. These flies bite and feed on the blood of cattle except for the face fly. It is well known that these flies decrease production by subjecting the cattle to constant daily annoyance, disrupting the normal grazing patterns, reducing weight gains, and lowering vigor / milk production. High populations of horn and face flies have been reported on cattle in the North Central Region. The most common methods of management for the horn and face flies include: impregnated ear tags, self-treating devices such as oilers, backrubbers or dust bags, and pour-on insecticides. An integrated fly management program using several different control strategies may be the best strategy for long-term fly control.

    Ear Tags: Use ear tags when fly numbers exceed 100 per side. It is recommended to use two tags per cow. Many brands of ear tags are registered and marketed under different names. Select a different class of insecticide or combination insecticide ear tags each season to prevent the development of insecticide resistant. Pyrethroid resistant horn flies occur in many locations in North Dakota. One of the advantages of ear-tags is that their cost is relatively low about $2-3 per head. Horn flies are easier to control with ear tags than face flies, because horn flies spend more time on the cattle and thus are exposed to the insecticide longer. Examples of some ear tags are:

Brand Name

Active Ingredient(s)


diazinon 20%
pirimiphos-methyl 20%

Cutter Gold

fenvalerate 8%
flucythrinate 7.5%
permethrin 10%

Ear Force Ranger, Car-Mac

Pyrethroid Combinators


  Self-Treating Devices: These devices can be effective if properly placed and maintained in loafing areas around water sources or shade areas. Devices that force the cattle to pass through and even get toxicant on the head have an added advantage of reducing fly populations. Insecticides registered for use in self-treaters include malathion, permethrin, fenvalerate, dichlorvos, to name a few.

    Pour-On Insecticides: Livestock sprays have not been widely used because they do not fit well with the traditional summer range management of North Dakota ranchers. Some current pyrethriods insecticides used for control of flies are CyLence (cyflutrhin), Saber (lambacyhlothrin), and Atroban (permethrin). These pyrethroids can provide up to 3 weeks of protection. It is easiest to spray on insecticides when a catchpan or crowded corral is available in the pasture to confine the cattle. Periodic spraying is recommended when fly populations are high. For getting good coverage, use a sprayer capable of developing at least 200 PSI with sufficient hose length for easy movement.

Janet J. Knodel
Area Extension Specialist Crop Protection
North Central Research and Extension Center
Minot, ND

South-Central ND

    The ND Ag Weather Network weather stations in this region recorded a trace of rain at Linton to 2 inches at Bismarck during June 16 to 22. Rain received this past week generally was welcome. However, portions of Emmons, Logan, and McIntosh counties received heavy rain and hail that caused extensive crop damage in localized areas. Estimates of unplanted cropland in this region range from 6 to 18%, with the higher level of unplanted acres in Barnes, Dickey, LaMoure, Ransom, and Sargent counties.

    Alfalfa, hayland, and pastures generally are in very good condition. Alfalfa and grass hay harvest continues but frequent rain events are hampering progress. Crop planting is essentially complete. Annual warm-season forages will continue to be planted. Most spring-seeded small grain are in the jointing stage or beyond. April-seeded small grain is in the boot- to early-heading stages. Most canola has begun flowering but very young stages of the crop can still be found. Field pea, corn, soybean, dry bean, and sunflower generally are in good condition. Growth of warm-season crops is modest due to cool night air temperatures. Some growers are reporting emergence problems of beans due to crusted soils.

    Weed control operations generally are completed in small grain for wild oat and are rapidly progressing for foxtail and broadleaf weeds. Growers are continuing herbicide application in corn, field pea, and flax. Herbicide application and between-row tillage also are beginning in soybean, dry bean, and sunflower.

    Growing degree units for the orange wheat blossom midge have totaled over 1300 units in Dickey, Ransom, and Sargent counties, as of June 22. The balance of the south-central counties are between 1100 and 1300 units. As 1300 units accumulate and wheat begins to head, the crop should be monitored for economic levels of this insect. Growers should continue monitoring sunflower fields for sunflower beetle. Alfalfa weevil and leaf miner are being found in alfalfa in most counties. European corn borer and diamondback moths are being trapped at the Carrington Center and will continue to be monitored to alert growers of potential threats during the growing season.

    Generally low levels of leafspot disease (tan spot, leaf rust, and septoria) continue to be present in most spring wheat fields. Assessments should be made as wheat begins to head whether fungicides are needed for control of head blight (scab) and leaf disease. Canola growers also should consider fungicide use on early-flowering fields if yield and disease potential are high.

Greg Endres
Area Extension Specialist/Cropping Systems
Carrington Research and Extension Center
Carrington, ND

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