Control of Insect and Related Pests of Livestock and Poultry in British Columbia

Mosquitoes

Host: Livestock and People

Description of Injurious Stages and Damage

Adult female mosquitoes cause annoyance to livestock by sucking blood. Animals are not able to graze properly, often resulting in reduced weight and decreased milk production. During mosquito outbreaks, cattle will gradually bunch up to avoid attack. If the attack persists, cattle will stampede, causing injury to themselves and damaging fences.

Summary of Life History

There are 46 species of mosquitoes known in B.C., most of which are injurious. All require water for their larval and pupal stages. Some species deposit eggs in permanent bodies of water such as sloughs, but our most troublesome species breed in temporary bodies of water created by melting snow or heavy rains. Species common to forest regions have only one generation per year. Species common to agricultural and urban areas in southern B.C. may complete their life cycle in 4 weeks or less and have several generations per year.

Control Recommendations

Provide a grass-free area, preferably on a rise or knoll, within the pasture where cattle can get some relief from mosquito attack. Dairy cattle can be sprayed with a livestock repellent; wipe-on repellents are available for horses.

Beef cattle: 0.012% permethrin spray or 0.5% permethrin backrubber solution.

Non-lactating dairy cattle: 0.05% permethrin spray. Do not apply within 30 days of freshening or within 7 days of slaughter.