Project duration: From October 1, 2001 to September 30, 2006

Issues and Justification

Stable fly, Stomoxys calcitrans, has emerged as a serious problem for grazing cattle in pastures and rangelands of North America. Blood feeding stable flies cause grazing cattle to bunch together, disrupting normal behavior. Resulting calf weaning weights are lowered by 20-30 pounds, and yearling weights by 30-40 pounds. Bunched herds trample vegetation in fragile soils and thereby accelerate soil erosion (blowouts).

The research in this project is vital to developing an IPM system for the stable fly on range and pastured cattle. Goals are to identify source(s) of the flies and to develop effective supplemental control methods that are practical for use in grazing production systems. The consequences of not providing a system for control of stable flies on range and pasture cattle will be a continuation of chronic irritation, along with losses in comfort and efficiency of the beef and dairy industries.

This multi-state project has assembled a critical mass of researchers with complementary skills and resources. Geographical replication and standardized methods will be used. Fly movement will be evaluated on spatial scales not possible by individual investigators.

Likely impacts of successfully completing the work are that beef and dairy producers will have the knowledge and tools needed to manage stable flies in range and pasture. This will mean that producers will be able to increase calf weaning weights, increase yearling growth rates, and increase lactation rates of milk cows. These increases in productivity will easily exceed the likely increases in control costs, and will thereby improve the efficiency of forage-based beef and dairy production, and increase the profit margins for these producers.