Remember these keys for successful fly control

Prepare for flies, then maintain the control momentum throughout the season.

March 15, 2017

6 Min Read
Remember these keys for successful fly control

Source: Bayer Animal Health


For cattle producers, the change in seasons brings much to anticipate—green grass, healthy calves and flourishing cows. A change in seasons also brings much to anticipate as far as summer pests. While the appearance of flies is challenging and costly, here are some steps you can take throughout the season to help minimize their impact.


Prior to the start of fly season, it’s time to do a little early “spring cleaning.” This can include:

  • Eliminating potential breeding areas by removing left-over hay and other spilled feeds from winter feeding; this should include tilling the areas around round bale feeders to help dry these areas out and reduce stable fly breeding

  • Cleaning facilities, particularly areas with manure, to eliminate potential breeding grounds

  • Ensuring standing water is limited to what is necessary

Beginning of Season

Once spring has sprung and fly season begins, it’s time for producers to implement their fly control plan. When doing so, it’s important to have a good understanding of the types of flies that pose the biggest threat to an operation.

Not all flies are the same, so knowing the type of flies you’re dealing with (and where they breed, rest and feed) is necessary to help you choose the best strategies and products to control them.



Horn Fly

Fresh, undisturbed manure

Spends majority of life on cattle

Takes blood meal from cattle

Face Fly

Fresh, undisturbed manure

On fence posts, trees, bushes, other objects

Feeds on saliva, tears, nasal mucus


Manure, mixed with moist decaying organic matter

Barns, walls, fences, weeds, other surfaces

Takes blood meal from cattle (and people)

House Fly

Manure, moist and/or decaying organic matter

Manure, contaminated  soil, fences, buildings, trees

Old feed, manure, waste, sweat, tears of animals

Horn flies and face flies are almost always associated with cattle on pasture. House flies and stable flies are most often found around confined cattle and their premises.  Once producers know what flies are an issue, they can better determine how to fight them, such as via the Defense Point system. The system works by dividing an operation into four key treatment areas where pests thrive – on animal, facility, environment and feed through – and choosing the products suited to those locations.


As spring turns in to summer, producers should take time to monitor and evaluate their fly control efforts and make any adjustments needed based on fly pressure. Some of the more common issues may include:

  • A resurgence of flies, often brought about by a weather change, for example, rainfall after an extended dry spell

  • An abundance of flies from not initially treating properly for fly control

  • Ear tags wearing out, especially in locations with longer fly

Fortunately, creating and implementing a mid-season strategy can still help producers defend against the impact of potentially damaging pests.


Once fly season ends, producers should take steps to prepare for the next season, including removing ear tags to avoid resistance issues. In addition, producers should take the time to evaluate what was most effective and determine any adjustments to make the next season.


Resistance Reminder

Pests can develop reduced susceptibility to an active ingredient over time. Rotation between products with different modes of action (MOA) can help reduce the risk of insecticide resistance.

It’s important for livestock producers to implement a strategy of rotating about every year and remember to rotate between different MOA groups, not just brands or active ingredients in the same chemical class. Modes of action available include:


  • Pyrethroids – Sodium channel modulators that disrupt the normal flow of sodium ions

  • Organophosphates – Cholinesterase inhibitors that prevent the breakdown of acetylcholine

  • Neonicotinoids – Acetylcholine receptor agonists that mimic the action of acetylcholine


Limiting pests’ exposure to any one insecticide MOA helps sidestep the potential impact of cross-resistance and helps reduce selection pressure for resistance by any mechanism, minimizing the emergence of new resistant pest populations.

There are a variety of insecticides available with different modes of action to help producers keep their method of fly control active.

In addition, producers also should consider the following rotation-related tips:

  • Rotate insecticides with different MOAsiii, not just different brands or active ingredients

  • Rotate late in the season to cut down on resistant overwintering fliesii

  • Discontinue using insecticide ear tags as soon as horn fly numbers decline in the fall, to minimize the flies’ exposure time to the insecticide and help ensure fly populations that proliferate later in the season remain susceptibleii

  • Rotate MOA classes between applications when applying insecticides more than once per season or yeari

  • Use insecticides at their full doses according to product label recommendationsi

  • If mixing insecticides as a short-term measure for a resistance problem, be sure each component of the mixture is from a different MOA groupiand use both at the full label


The Defense Point System

Flies and lice can wreak havoc on the productivity of livestock. They can transmit disease, destroy property and disrupt feeding — and cattle that aren’t eating aren’t growing.

 That’s why Bayer Animal Health introduced its Defense Point System, which offers a specific strategy for effective pest control throughout a producer’s operation. The system works by dividing the operation into four key treatment areas where pests thrive, and identifying the products best suited to those conditions.

Defense Point 1 – On-Animal

Animals are ground zero for pest damage. Many pests spend the majority of their life cycle on cattle and take blood meals several times a day. An infected pest can also transmit disease, which can lead to serious loss of productivity. Products that can be used on animal include pour-ons, on-animal sprays and dusts.

Defense Point 2 – Facility

Where cattle sleep and take shelter is a prime location for pests to pass from one animal to another. Treating the facilities on an operation may aid in stopping the spread of pests among livestock. Products to treat facilities include sprays and baits.

Defense Point 3 – Environment

Pests may use the areas beyond the immediate housing facilities to breed and replenish their numbers. Treating potential pest breeding areas that surround livestock buildings and horse stable areas may play a significant role in reducing the pest population. Grassy areas surrounding lagoons and feed spillage areas are examples. Products that can be used in the general environment of an operation include sprays and baits.

Defense Point 4 – Feed-Through

Several species of flies flourish on the natural actions of cattle, both feeding and laying their eggs directly in cattle manure. With the use of a feed-through product, producers can take a proactive effort toward disrupting the fly’s life cycle. Products that can be used as a feed-through include oral larvicides.

With this approach, producers can take a comprehensive approach to pest control, maximizing their efforts to reach their entire operation.

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