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Published on: July 30, 2017
Exposure of Bed Bugs to Metarhizium anisopliae at Different Humidities
Kevin R Ulrich1, Mark F Feldlaufer2, Matthew Kramer3
1Department of Entomology, University of Maryland, College Park, MD 20742. kru@umd.edu.
Abstract:
Bed bugs Cimex lectularius L. were exposed to conidia (spores) of the entomopathogenic fungus Metarhizium anisopliae by feeding, aerosol spray, or contact with a treated surface. Feeding experiments demonstrated that bed bugs were innately susceptible to this fungus. However, only at 98% humidity were mortality rates high, regardless of whether bed bugs were sprayed with a fungal solution or contacted a treated surface. Mortality in treated bed bugs at ambient humidity did not increase when these bed bugs were kept in aggregation with other bed bugs that had recently blood fed to repletion. Based on these laboratory studies, we conclude that M. anisopliae is a poor pathogen for use in control of bed bugs, particularly at humidities that would likely be encountered under field conditions.
Insights
Metarhizium anisopliae, an entomopathogenic fungus, shows limited effectiveness for controlling bed bugs (Cimex lectularius L.). High humidity is crucial for significant bed bug mortality when using this fungal agent.
Area of Science:
- Entomology
- Pest Management
- Microbial Control
Background:
- Bed bugs (Cimex lectularius L.) are significant public health pests.
- Effective and environmentally friendly control methods for bed bugs are needed.
- Entomopathogenic fungi are explored as potential biological control agents.
Purpose of the Study:
- To evaluate the efficacy of the entomopathogenic fungus Metarhizium anisopliae against bed bugs.
- To determine the impact of different exposure methods and humidity levels on fungal efficacy.
Main Methods:
- Bed bugs were exposed to Metarhizium anisopliae conidia via feeding, aerosol spray, and surface contact.
- Experiments were conducted under varying humidity conditions (ambient and 98%).
- Mortality rates were assessed, and the effect of aggregation with blood-fed bed bugs was observed.
Main Results:
- Bed bugs exhibited innate susceptibility to Metarhizium anisopliae when ingested.
- High mortality rates were only achieved at 98% humidity across all exposure methods.
- Mortality did not increase at ambient humidity, even with aggregation of treated bed bugs.
Conclusions:
- Metarhizium anisopliae demonstrates poor efficacy for bed bug control under typical field humidity conditions.
- High humidity is a critical factor for the effectiveness of this fungus against bed bugs.
- Further research may be needed to optimize fungal application or explore alternative biological control agents.
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