New Guide Charts Path to Improved IPM for Fly Pests of Cattle

As researchers dedicated to veterinary entomology and economic entomology, we each found our way into this field differently, but we’ve nonetheless arrived at a common pursuit to improve the management of flies in animal production. Consider our backgrounds:

Katy grew up on a beef cattle farm in rural middle Tennessee. Each spring when flies appeared on the cattle, her family knew it was time to bring out the fly spray. There was never any counting or species identification involved. When Katy’s stepfather took over the daily operations of the family’s cattle farm, he didn’t know the first thing about raising cattle, but he was willing to try just about anything. He started asking farmers down the road, people he ran into at the local co-op, and telling Katy to ask her professors at school, “What do you do to handle XYZ?” His curiosity led her to realize that the way things had always been done on the farm might not be the best way and sparked her interest in producer decision-making from a pest control perspective.

At the same time, Becky would speak with producers and they would all agree that flies on livestock were a normal occurrence, and producers managed flies to keep them from getting worse. To her, it seemed that producers wanted to reduce flies on cattle but were not aware of the different reasons to manage flies or (more importantly) when and why one manages flies on a farm. This is important, because time is a producer’s most valuable resource, and many producers are balancing another job while maintaining the family farm. It quickly became evident to Becky that producers were trying their best but may not have realized the potential benefits to proper fly management and the reasons to (or not to) manage their flies. It felt to her that producers had given up on managing flies and were not thinking about flies as a solvable problem that could be successfully managed with data; instead, producers treated flies as an endemic pest and a part of the normal farm community.

As two people with very different past experiences, our conversations always overlapped about the costs of flies on cattle. When we first sat down to brainstorm, we knew we wanted to approach veterinary entomology from an economic perspective. Katy had previously interned with Corteva Agriscience, where she saw firsthand the damage that insect pests can inflict on row crops. She wanted to take her knowledge of that industry and compare it to veterinary entomology. Horn flies, face flies, and stable flies are economically important pests of animal agriculture, particularly beef cattle. We know that extensive research exists regarding the biology and management of these pests, but very few researchers have examined the costs associated with these flies. Most papers evaluate weight gain, but few actually look at those losses and expenditures—in other words, the economics of the flies. The most recent estimates we could find of how these flies impact animals economically were written 40 years ago, something Katy’s master’s advisor (and collaborator) agreed was outdated.

So, in a new article published last week in the open-access Journal of Integrated Pest Management, we along with our brilliant coauthors lay the foundation for developing a transdisciplinary integrated pest management (IPM) approach that considers the economics of controlling flies in animal production. The goals of this paper are to:

• highlight losses and expenditures associated with the damages caused by these flies
• discuss current management strategies for the system
• propose industry needs in terms of research and mathematical modeling gaps and producer education to enhance sustainable beef production

Currently, economic impacts of biting flies on cattle production are associated with losses in production and are evaluated by measuring performance and efficiency parameters such as weight gain, weaning weights, and feeding efficiency in the form of gain-to-feed ratios. Recent research has shown that cattle producers’ spending on horn fly control methods is associated with producer and farm demographics, producer perceptions of horn flies, and management practices, with management costs varying based on a producer’s level of education and income, breed of cattle, herd size, and control method used. Tennessee and Texas cow-calf producers surveyed indicated these producers primarily rely on insecticides for preventing and treating pests of cattle and have never used or discontinued other options. These producers also ranked pests based on perceived cost and damage, with filth flies ranked the highest.

Producers who use IPM attempt to control pests with a combination of tactics producing the best outcomes, but producers may not be making these decisions based on economic, ecological, or sociological consequences. There is a long-term and continually growing need to refine IPM to increase producers’ profitability by helping producers make data-driven and sustainable decisions for pest management. In this paper, we explore reasons and ideas for how producers can use data to sustainably manage flies while raising healthier cattle that have a reduced negative impact on climate.

Rebecca Trout Fryxell, Ph.D., is an associate professor and Katy Smith, is a Ph.D. student and graduate research assistant in the Department of Entomology and Plant Pathology at the University of Tennessee.