Four key components of effective fly control

Flies are a nuisance. They are irritating to cattle, horses, stock dogs and, of course, humans. More concerning, they are also vectors for diseases. An integrated pest management program (IPM) is important to control fly popula­tions. Effective fly management is especially critical in feeding oper­ations and dairies because of their confined nature.

No one practice is sufficient to control flies. Effective IPM plans use a variety of practices and control methods to keep fly populations in check, and these measures should start well before fly season begins. There are four important branch­es of an IPM program: cultural, physical, biological and chemical. While each branch is important, the cultural and physical branches are the fundamental components of fly control.

Cultural practices make a world of difference in fly management. These practices include manure management, regular cleaning of spilled milk and feed, removal of vegetative buildup and soiled or de­caying bedding in cattle areas, and landscape maintenance. Removing these breeding sites for flies dramat­ically reduces their population in a cattle operation.

Additional cultural elements also help fly control. These prac­tices include removing tall grasses and weeds, where flies can rest in the plants, regularly cleaning and moving calf hutches and pens, and ensuring that pens are well venti­lated.

Physical efforts are perhaps the most obvious method of fly control, though it is not always the easi­est. Structures and facilities can be designed to deny flies access to locations, or at least make the areas less hospitable for them. Patching or sealing cracks in structures, in­stalling mesh screens over windows, and sealing around electrical outlets can close off entry points for flies. Installing fans that provide a down­ward and outward air flow reduces fly activity in buildings. Addition­ally, consider strategically placing non-insecticidal sticky, jug or bag traps to aid these efforts.

Biological control involves harnessing the power of natural predators of flies. Parasitic wasps, predatory mites, predatory beetles and fly pathogens are all used to control flies. These methods interrupt the lifecycle of the fly. For instance, predatory beetles feed on fly larvae found in dung, while parasitic wasps lay their eggs inside fly pupae.

Chemical control is the final component of a well-managed four-branched IPM program. Most producers are familiar with the conventional chemical control methods for flies. These include foggers, baits, perimeter sprays and on-animal treatments. When using these products, remember to rotate active ingredients so flies do not become resistant. This is most important with baits.

Chemical control also includes feed-through insect growth regula­tors (IGRs). Feed-through products prevent the emergence of adult flies. These products work by delivering an important active ingredient di­rectly to cattle, where it is eventual­ly passed into the animal’s manure. Flies then lay their eggs on the manure, and the IGR interferes with the lifecycle of the fly. This process prevents biting, breeding adult flies from developing out of the eggs laid in the manure.

A common free-choice MFA cattle mineral used for controlling horn flies on pasture cattle is Ricochet Altosid IGR Shield Mineral. Another IGR is Clarifly, with the active ingredient diflubenzuron, which has a label for four species of flies. It is fed to confined cattle and also approved for swine, horses, goats and sheep.

To use a feed-through product, begin feeding a product about a month before flies begin to appear and continue until about a month after the first frost. This program of 30 days on each side of fly season suppresses fly activity early and reduces overwintering pupae. If a feed-through product is started late, after flies are already active, additional fly control measures will be required. Feed the product to animals of all ages to treat as much manure as possible.

As you implement an IPM plan, monitor its effectiveness. Evaluate fly populations throughout your operation with traps and speck cards. Record which steps are successful and where additional improvement is needed. By carefully evaluating your IPM program, you can make appropriate adjustments as needed.