Controlling Insects on Your Farm

Controlling biting insects such as flies and mosquitoes on your deer or elk farm is important as these insects are not only annoying to your animals, but may carry diseases as well. The challenge is to maximize effectiveness of your insect control programs at a cost you can afford.

Area-wide management programs that involve treating rivers and streams with microbial insecticides have been successful, but require good timing and co-ordination. More localized management practices include smoky fires to repel flies and moving livestock away from aquatic sources of infestation.

When considering insect control options for your deer and elk, producers should calculate potential costs and logistics and the amount of stress on the animal.

Spray concentrates

Spray concentrate formulations include emulsifiable concentrates, flowables and wettable powders that are diluted before the application.

Most concentrates are diluted with a large amount of water and applied with high pressure equipment to provide a coarse spray. The objective is to wet the animal thoroughly. A few concentrates can be diluted with low volume oil solvents and applied as a fine mist to moisten the animal’s surface.

Spray treatments offer the advantage of complete body coverage. They usually provide good initial control, but their residual effectiveness may be short lived. To spray livestock, producers need a corral, application equipment and a source of water.

Pour-ons and spot-ons

Pour-ons are formulated so a small amount of insecticide can be applied on the animal’s spine. Most are ready to use and require no further dilution. Some pour-ons are systemic insecticides that move into the animal and circulate through the body. Other non-systemic product spread across the body surface with body oil and moisture.

A spot-on differs only in that a small of material is applied at one location on the spine.

Pour-ons are easy to use and allow an exact dosage to be applied to each animal. To apply, producers will need a corral and squeeze chute. Some pour-ons can be more easily applied with a syringe gun. Residual effectiveness varies, but it is good for two or more weeks.

Insecticide ear tags

Ear tags can be impregnated with insecticide concentrate that is slowly released over an extended period.

The tag is a controlled-release applicator, but the amount of insecticide that is released decreases over time.

Ear tags are not systemic. Instead, the insecticide is spread over the body as animals groom themselves and rub against each other.

Producers will need an ear tag applicator, corral and a squeeze chute with a head gate.

Ear tags can be labour intensive, especially the time animals are tagged. However, they are also cost effective since they provide three to four months’ control of a susceptible target pest.


Dust formulations combine a low concentration of active insecticide with a dust diluting agent. They can be applied with hand shakers, mechanical applicators and self-treatment dust bags.


Feed-throughs combine a small dose of insecticide or insect growth regulator with feed or minerals. Most are mixed and formulated by the feed or mineral supply company.

Insecticide boluses can also be classified as a feed-through.

Feed-through chemicals pass through the animal’s digestive system and are excreted in the manure. The chemicals control fly maggots or the larval stage of the adult fly. They do not control adult flies.

Feed and minerals must be consumed continuously during the fly season so that the manure is always treated.

Self-treatment back rubbers

Back rubbers can be built by wrapping burlap bags around a cable or chain and hung where livestock can pass under them. They are charged with insecticide concentrates that are diluted with approved base oils following label instructions.

Apply one gallon of diluted solution per 20 feet of homemade burlap back rubber.

To get maximum benefits, place the back rubbers in alleys or locations where animals must pass regularly, such as between pastures and feeders, water or minerals. Free choice locations do not ensure regular use, but livestock can learn to use the back rubber in a shady, loafing area.

Their effectiveness is determined not only by the insecticide, but with frequency of use.

Dust bags

This self-treatment device operates under the same principle as a back rubber. Weatherproof dust bags are commercially available, but high humidity and steamy weather sometimes impair their effectiveness.


These include a variety of mechanical and electrical devices used to lure and destroy insects. Some examples are electrical bug zappers, mosquito magnets, fly traps, and sticky strips. They can be effective in reducing the number of insects in localized areas such as barns and handling facilities, but are less effective in pastures.


Insects do have natural predators such as birds, dragonflies and reptiles. Farmers should make their environment friendly and attractive to these insect-eating creatures.

Source: Louisiana State University news release