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Research Project: Management of Filth Flies

Location: Mosquito and Fly Research

Title: Biological control of livestock pests: Pathogens

Author
item Weeks, Emma
item Machtinger, Erika
item Leemon, Diana
item Geden, Christopher - Chris

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 3/1/2018
Publication Date: N/A
Citation: N/A

Interpretive Summary: Livestock around the world are subject to attack from a variety of pests including ticks, mites, lice, biting and non-biting flies and others that cause direct effects on production economics and transmit devastating diseases. Insecticides have long been the mainstay for livestock pest control but there increasingly fewer options to choose from, many pests are resistant to products registered to control them, and there is increasing public demand to reduce overall use of insecticides. This article by scientists with the University of Florida, Pennsylvania State University, the Queensland Department of Agriculture and Fisheries (Australia), and USDA’s Center for Medical, Agricultural and Veterinary Entomology (Gainesville, FL) reviews the status and potential of insect pathogens as management tools for livestock pests. Parasitic nematodes have potential against a wide range of pests but the narrow range of environmental conditions that they can tolerate limits their use as practical management tools. Fungal pathogens have the greatest overall potential for use as microbial insecticides because of their ease of use, low cost, good storage qualities, and the fact that they can be formulated in many ways and applied with conventional application equipment. The main drawback to their use is the long time that it takes them to kill the target pest, but progress is being made on several fronts to speed up their kill rates.

Technical Abstract: Interest in biological methods for livestock and poultry pest management is largely motivated by the development of resistance to most of the available synthetic pesticides by the major pests. There also has been a marked increase in organic systems, and those that promote animal welfare by reducing animal densities and allowing greater freedom of movement. Such systems, especially organic operations, are in need of new tools and strategies to manage pest problems. This chapter reviews the status of entomopathogenic fungi, viruses, and nematodes for management of pests of livestock and poultry production. The pests covered here are limited to the research that has been conducted to date, but include biting and nuisance flies, ticks, poultry ectoparasites, and litter beetles. Many of the same pests affect horses as well, although little work has been done in this area. The fungal pathogens Beauveria bassiana and Metarhizium anisopliae s.l. have received the most attention and have been evaluated against most of the major livestock and poultry pests. These pathogens have the greatest potential for practical use, but more work is needed to identify efficacious isolates and develop formulations for both on- and off-host use. The slow kill rate of these pathogens has been considered a liability in the past, but a growing body of work has demonstrated important sublethal effects of infection that includes reduced feeding, movement, and pathogen transmission. Two pathogens of house fly, the fungus Entomophthora muscae and salivary gland hypertrophy virus, are effective under some conditions but have biological characteristics that have limited their development as practical management tools. Entomopathogenic nematodes (Steinernema and Heterorhabditis spp.) also have potential but are limited by environmental constraints, especially temperature and substrate moisture. Discovery of, or selection for, strains with wider environmental tolerance could broaden the range of situations where they can be used effectively.