Don’t Fall Behind: Late Season Feeding with the 30/30 Approach for Fly Control

Published on Thu, 07/21/2022 - 11:12am

Don’t Fall Behind: Late Season Feeding with the 30/30 Approach for Fly Control.

 Article courtesy of Central Life Sciences.

 Before the fall approaches and cold weather is near, it’s critical to continue late-season feeding of Altosid® IGR to prevent the emergence of overwintering flies. Then, come next spring, you’ll be glad you did.

Fly activity is influenced heavily by weather, with active fly presence lowering as the temperatures drop in fall and pupae begin to overwinter. The following spring, the warmer temps mark the start of the fly season when overwintering horn flies start to emerge, ready to feed on cattle with painful bites and spread disease-causing bacteria.

To achieve the best results with Altosid® IGR and limit horn flies on cattle, we recommend following the 30/30 approach. The 30/30 approach helps account for the variability in weather patterns to maximize control of overwintering fly pupae. These overwintering flies will be the first to emerge once the weather warms, jumpstarting fly populations in the spring. By feeding later into the fall, you can limit the total number of overwintering flies. Once spring arrives, an earlier start to your fly control program protects against temperatures warming earlier than you anticipated, putting you behind schedule right from the start of your fly control program.

The Problem
Fly infestations significantly impact production on beef cattle operations. When left untreated, horn fly infestations can reach up to 4,000 flies per animal, staying on the cattle both day and night, which translates to a substantial economic loss. For every 100 animals, that results in an average of 1,600 pints (200 gallons) of blood lost per herd, per season, which averages 6.67 pints (0.833 gallons) lost per day. In addition to causing blood loss, a horn fly infestation also leads to increased cattle stress and annoyance. This can cause cattle to burn excess energy to combat the flies, interrupt grazing patterns, and cause cattle bunching. Altosid® IGR from Central Life Sciences helps provide producers with protection against the damaging impact of horn flies. The product does not directly affect production but helps provide control of the nuisance horn flies that do. Altosid® IGR is mixed into cattle feed and passed through the cow’s digestive system and into manure, where it interrupts the horn fly life cycle. This prevents the emergence of biting adult flies that eat into your beef cattle margins and cause discomfort to your cattle. In addition, the mode of action of the active ingredient (S)-methoprene is specific to insects and is not harmful to birds, fish, reptiles, mammals, or beneficial insects.

30/30 Approach
With the annual spring emergence of flies starting the pest’s life cycle each year, limiting the number of overwintering pupae is an essential step in controlling horn fly populations before the season begins. However, precisely planning exactly when to target the overwintering pupae can be challenging given the unpredictability of seasonal weather patterns. For example, Madison, Wisconsin, typically experiences the first frost of the season in the first week of October. However, the date has been recorded as early as September 12 and as late as November 12.

It is also common for many regions of the country to experience several weeks of warm weather after the first recorded frost of the fall/winter season or before the final frost in spring. When you need to account for the unpredictable nature of frost dates, Central Life Sciences recommends taking a “30/30” approach to fly control on your operations.

The “30/30” approach encourages operations using Altosid® IGR to start including the products in their feed or supplement early in the spring.

Get started with the 30/30 approach with these three easy steps:
1. Know when to start feeding, which is approximately 30 days before the average daily daytime temperatures reach 65° F. This is when overwintering flies emerge.
2. Continue feeding through the fall, 30 days after the first frost has been recorded. This is to help reduce overwintering pupae, giving you a jump start on the next fly season.
3. Implement a comprehensive Integrated Pest  Management (IPM) program that includes biological, physical-mechanical, and cultural efforts to reinforce your fly control.

Put an IPM program into place to keep cattle performing their best and maintain control of your bottom line. An IPM program is a pest control strategy that uses an array of complementary methods, best cultural practices, and fly control products. An effective IPM program should include these three key components:
1. Cultural Control
2. Biological Boost
3. Chemical Containment

After a proper IPM program has been established and put into action, it’s essential to continually monitor fly populations to evaluate the effectiveness of the program. Track fly populations with speck cards and fly traps, and adjust the program as needed to maximize control efforts.

The Solution  
To account for the unpredictable nature of frost dates, Central Life Sciences recommends taking a “30/30” approach to horn fly control on beef operations. Feeding rates are 1.13 mg per kg per day for Altosid® IGR, though users should always consult the product label for exact instructions. Maintain the process into the fall season until 30 days after the first frost has been recorded. Countless studies have shown that flies can cause severe economic damage to beef operations. The effects are very real to producers, and the importance of controlling fly populations has never been more critical.

By following a “30/30” approach, producers can get ahead of the horn fly population in the spring before it builds to a level that exceeds the economic threshold. By continuing to feed 30 days past the average first frost date in the fall, producers can reduce the total number of overwintering pupae, thus giving them a head start on the population for the following year. When incorporated into a complete IPM program, the use of Altosid® IGR with a “30/30” approach can help producers account for the unpredictability of the seasons and significantly lower horn fly populations while increasing cattle comfort and profitability.

For more information on late season feeding, IPM tips for beef cattle and the “30/30” approach, visit   

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