By Dr. Denise Heard
U.S. Poultry & Egg Association
Special to Poultry Times
TUCKER, Ga. — One of the largest management problems facing the poultry industry today is pest control. Poultry operations can be infested by a variety of pests such as flies, mites, lice, bed bugs, fleas, beetles, ants, chiggers, gnats, mosquitoes, and more. But by implementing innovative integrated pest control measures, producers can minimize the damage from pests.
Pesticide treatments are highly regulated chemicals and may have hazardous potential for bird tissue residues and environmental contamination. Any pesticide treatment must be tailored to the particular pest in question. In many cases, the bird and environment must be treated simultaneously.
Over the past year, the U.S. Poultry & Egg Association published the findings of a completed research project and approved a new study both aimed at providing much needed insight into potential new pest control strategies. Following is a summary of the studies and their potential benefits towards improving pest control in the poultry industry.
House fly control
To control house flies, the poultry industry is estimated to spend $20 million dollars annually on pesticides alone. This estimate does not include the cost of animal loss due to house fly vectored pathogens causing disease, the cost of labor for pesticide application, or litigation that can be taken by residents living near production facilities due to increased fly numbers affecting their property values. One potential option to control pest flies is the integration of biological control agents into a layer facilities’ integrated pest management (IPM) program.
Many natural antagonists of the house fly are found within the environment of the manure pit. Augmentative releases of these antagonists and introduction of pathogenic organisms can help lower house fly populations to manageable levels.
Dr. Erika Machtinger and colleagues at Pennsylvania State University completed a research project that evaluated the use of biological control agents to decrease house fly populations. The most promising of these biological control agents on a commercial level are parasitoid wasps and the entomopathogenic fungi Beauveria bassiana. Parasitoid wasps are commercially available and commonly released into poultry systems as a form of biological control, but more research needs to be done to determine which species or combination thereof would be the most effective in different geographic locations. The fungi, B. bassiana, has been widely studied as a form of biological control for house flies in layer facilities as well but has not been widely adopted by the industry. Further research into improving its effectiveness and ease of use could change this trend.
The three objectives of the research were to collect new fungal isolates from flies in poultry facilities and screen them to identify strains with fast kill times, to test the most promising strains and subject them to selection for further improvements in kill times, and to ensure their compatibility with the most important natural enemies of flies (e.g., three species of parasitic wasps and the beetle predator Carcinops pumilio).
Results included the collection of five new isolates of B. bassiana that had mean survival times under eight days, an improvement from currently marketed B. bassiana products. The strains identified were the ones that were consistently the most virulent and produced the highest numbers of conidia on cadavers in fly-to-fly passages. Selection for faster-killing strains shortened the average time until death by three days, from 7.6 to 4.7 days, after nine generations of selection. Spalangia endius was the most resilient to the B. bassiana applications, whereas Spalangia cameroni and Muscidifurax raptor had decreased survival when B. bassiana was applied.
Overall, the B. bassiana strains isolated from house flies killed greater numbers of flies than the negative control. In parasitoids, all strains had a more limited effect than was observed in the house flies, except for in S. endius, in which there was no effect. The susceptibility of these house flies to the treatments, and the lack thereof, in all parasitoid species is a good indicator of the usefulness of field collected strains of B. bassiana and their use as a biological control tool. Given that the strains each demonstrated different traits in their infection of house flies, further research is needed to see the extent of each of these traits and if they could be useful for biological control.
Pesticide embedded paint
Some pest-control technologies that are currently in use for poultry facilities primarily rely on spraying pesticides to disinfect waterers and feeders. Despite its simple implementation, the current spray-based method is limited by multiple factors. Only a nominal percentage of the sprayed pesticide goes directly to the target pest. Further, sprayed pesticide can become aerosolized which can cause respiratory problems to poultry upon inhaling. Moreover, it can be readily degraded even at the ambient condition. Dr. Gibum Kwon at the University of Kansas is conducting ongoing research to investigate how ‘pesticide-embedded paint’ can overcome these limitations.
Specific ongoing research aims include synthesizing and characterizing pest-repellent paint by utilizing all plant-derived materials, optimizing the paint’s pest-repellency by modulating various experimental parameters, comprehensive and comparative repellency tests by using three independent methods that involve area preference test, mortality test and cage test, and evaluating long term efficacy and testing real world applications.
The paint is expected to demonstrate a sustained pest-repellency that can endure for at least 24 months. This will be an improvement to the currently used pesticides with relatively shorter service life, due to their susceptibility to degradation and weathering. A versatile pest-repellency will be demonstrated by the paint showing efficacy effective against a wide range of pest species in poultry facilities, including wingless pests such as ants and ticks, as well as flying pests such as mosquitos and flies.
Dr. Denise Heard is director of research programs with the U.S. Poultry & Egg Association based in Tucker, Ga. She can be reached by e-mail at dheard@uspoultry.org.
