Managing horn flies - effective control methods for cattle

By Scout Nelson

Horn flies pose a significant threat to pasture and rangeland cattle in Nebraska, impacting milk production and weight gain once their population surpasses the Economic Injury Level (EIL). As spring weather conditions fluctuate, predicting horn fly emergence becomes challenging. With proper management strategies, farmers can effectively combat horn fly infestations.

Now is the time to develop or refine horn fly management plans for 2023. Evaluating last year's strategies and making necessary adjustments is crucial for successful fly control. Selecting the most suitable control method depends on factors such as efficacy, cost, convenience, and herd management practices.

Several delivery methods are available for horn fly control, including dust bags, back rubbers, oilers, pour-ons, animal sprays, oral larvicides, insecticide ear tags, compressed air application, and traps. Each method offers unique benefits and considerations.

Dust bags, back rubbers, and oilers are effective when strategically placed in forced-use arrangements, encouraging cattle to pass under them regularly. Pour-ons and animal sprays provide temporary relief and require reapplication throughout the fly season. Oral larvicides, such as feed additives and boluses, disrupt horn fly larval development in manure pats, offering long-term control.

Insecticide ear tags release small amounts of insecticide over time, providing continuous protection against horn flies. Timing is critical, and tags should be applied during late May or early June for maximum efficacy. Compressed air application devices, like the Vet Gun™, offer targeted insecticide delivery and provide control for several weeks.

Traps, such as the Bruce fly trap, physically capture horn flies, reducing overall population when used consistently. Studies have shown that traps can significantly decrease horn fly numbers, especially when employed in force-use situations.

Farmers should assess their operation's needs and choose control methods that align with their goals and resources. Implementing comprehensive horn fly management plans early in the season can mitigate economic losses and ensure the well-being of cattle throughout the fly season.

Photo Credit -gettyimages-prill