"Biological control of pest populations would boost efficiency for meat and milk producers, and relieve both urban and rural dwellers of a summertime nuisance." - Roger Moon

Minnesota is well known as a summertime habitat for flies. Many of these flies are considered to be pests both to people and livestock. Over the last three centuries, four such fly types have been accidentally introduced to the U.S. from their native range in Europe and Asia, causing various problems for rural and urban dwellers around the state:

Stablefly - will bite people, pets, and larger animals. In the case of beef cattle, it can actually act as an inhibitor to growth by forcing cows to bunch together in defense, which leads them to experience heat stress and waste energy that would otherwise be directed toward growth (the same condition is believed to afflict dairy cattle). Horses and dogs also attract this fly, causing them to stomp when bitten on the legs.

Hornfly - reduces the growth rate of pastured calves in the beef producing industry.

Facefly - spreads a bacterium that causes pinkeye in cattle.

Entomologists believe that many kinds of beneficial fly-eating insects dwell naturally within the native ranges of these flies. The goal of this project (MIN-17-050) is to identify fly-eating candidates in Asia and Europe and determine whether or not they would be suitable for deliberate release in Minnesota to improve biological control of the pest flies throughout the state.

Method

This project began in 1997 as an extension of previous research conducted in the area of natural biological control. While we have found that natural enemies native to Minnesota exert a degree of natural control on the introduced flies, those pest populations are still able to grow in spite of the native parasites. Our goal is to find better enemies in the pests' native range and re-unite them with the pests in Minnesota to achieve more effective control throughout the state. Similar efforts to control other pests have led to varying degrees of success, including cases where no further measures are necessary to control those pest populations after the beneficial species were introduced.

Very little information is available about natural enemies of flies in Old World habitats, so much of our initial work has gone toward surveying native ranges for possible beneficial species. Once potential enemies are identified, we will bring them into the U.S. through a quarantine procedure that excludes possible animal pathogens (bacteria/viruses) that could prove harmful to domesticated animals. We will then study the life histories of these insects to learn how to rear them and test their host range to determine whether or not they might kill other desirable insects that we don't want to eliminate. Once the candidate enemies have been screened, then further study will evaluate their potential to make their introduction worthwhile.

Results

We have identified five species of parasites (natural enemies) from Russia and Kazakhstan that are not already present in Minnesota. Thissummer, I will return to Russia and Kazakhstan to establish colonies for lab study.

There are approximately 20,000 horse owners and 12,000 beef and dairy cattle operations throughout Minnesota. They would all be at least indirectly affected by the success of our research, as they would experience fewer flies around their animals. It is difficult to place an economic value on the comfort of horses, but productivity of dairy and beef cattle would increase because the presence of flies increases the cost of production. For example, the four species listed above are together estimated to cause approximately $75 million in losses per year to Minnesota livestock and poultry industries (beef/dairy cattle, horses, hogs, and poultry) in the form of added inputs. Further costs (estimates not available) are incurred by residential households on related items, such as window screens. In particular, an increase in biological control of the horn fly on pastured cattle and stable fly on dry lot cattle would result in greater efficiency as producers could produce more beef with the same inputs.

It is too early to estimate the potential impact of this project on the above estimates, but further research will determine the realized potential. Depending on the difference that we can effect in fly abundance, the benefits here could be minimal to modest. Natural biological control is permanent, however, which would aid producers in their long-term farm management and allow them to allocate their time and financial resources to other areas of their operations. It is possible that some of the new parasites could be raised commercially for purchase and release as natural fly killers. At the same time, our research could affect chemical companies who market throughout the state, as pesticide sales would diminish to a degree.

Existing control methods for these flies rely mainly on insecticides. The introduction of fly-eating insects would provide a more effective biological alternative to chemically based pest control. While the extent of future chemical reductions are impossible to estimate, the degree to which we can alleviate pests through biological means can only reduce the amount of insecticides used around animals and people.

This research will be particularly beneficial in the area of animal comfort, both for food-producing animals, as well as dogs and horses. Not only does this improve their lives, but also the morale and lives of their owners. If successful, this project would reduce the number of flies that similarly act as a nuisance to individuals, families, communities, and outdoor businesses from late spring to early fall. It is impossible to estimate the degree to which pest populations could be reduced in residential/recreational areas. However, pests are known to represent a significant hindrance to many outdoor activities during the summer months.

Minnesota County
All Counties

Primary Researcher
Roger Moon
rdmoon@umn.edu

Participating Individuals
Kevin Janni - Biosystems and Agricultural Engineering David Ragsdale - Entomology George Heimpel - Entomology David Halvorson - Veterinary Pathobiology Sally Noll - Veterinary Pathobiology
1 Undergraduate Students
1 Graduate Students

Participating Institutions
Legislative Commission on Minnesota Resources (LCMR)

Department
Entomology

Government Funding Type
Federal
State

Additional Funding Information
Average annual funding is $22,320.00