Understanding and managing phorid flies

Phorid flies. Photo: ©Gene White

Phorid flies, also known as humpbacked or coffin flies, are small nuisance pests found worldwide in various habitats, including homes, hospitals, and agricultural settings (Disney, 1994). This article explores the biology and habits of Phoridae flies and provides effective control strategies to manage infestations.

Phorid flies undergo complete metamorphosis, progressing through four life stages: egg, larva, pupa, and adult. The duration of each stage is influenced by environmental conditions such as temperature and humidity. These flies are attracted to decaying organic matter, such as rotting fruits, vegetables, animal carcasses, and garbage. They can also infest drains, sewage systems, compost piles, and even breed in mushrooms, posing a significant threat to mushroom crops (Disney, 1991; Disney, 1994). Phorid fly larvae feed on decomposing materials, fungi, and dead animal tissues using their specialized mouthparts.

Effective Control Strategies:

Controlling phorid fly infestations requires a systematic and targeted approach. By implementing the following effective control strategies, you can successfully manage and eliminate these nuisance pests from your environment:

1. Identification: Accurate identification of phorid fly species is crucial for implementing the appropriate control strategy. Misidentification can lead to ineffective treatment options.

2. Inspection: A critical step in effective phorid fly control is conducting a thorough inspection of the infested area. This inspection aims to identify and eliminate breeding and feeding sources, which are key to reducing the fly population. During the inspection process, it is important to be thorough and meticulous. Here are some common breeding sites to focus on:

1. 1. Drains: Phorid flies are frequently found breeding in drains, particularly in areas with organic debris buildup or sewage leaks. Inspect drains thoroughly, including sink, floor, and shower drains, and ensure they are clean and properly maintained.
   2. Trash containers and dumpsters: Phorid flies are attracted to rotting organic matter, making trash containers and dumpsters prime breeding sites. Inspect these areas, paying attention to any signs of decaying waste. Proper waste management, including regular cleaning and timely disposal, is essential.
   3. Rotting produce and recycle bins: Fruits, vegetables, and other organic materials that have started to decompose are attractive to phorid flies. Inspect areas where rotting produce is stored, such as kitchens, pantries, or outdoor compost bins. Additionally, check recycle bins for any discarded organic matter that may serve as a breeding site.
   4. Grease traps and garbage disposals: Phorid flies can breed in grease traps or garbage disposals that have accumulated organic debris. These areas should be inspected and cleaned regularly to prevent fly infestations.
   5. Crawlspaces and areas with accumulated organic matter: Phorid flies may find suitable breeding conditions in crawlspaces, basements, or areas with accumulated organic matter, such as leaf litter or decaying plant material. Inspect these areas thoroughly and take measures to eliminate or manage the organic debris.

Dr. Mohammed El Damir, BCE

3. Residual Insecticides: In certain situations, the use of residual insecticides can provide short-term relief. Apply them as crack-and-crevice treatments or spot treatments in areas where phorid flies are observed or rest. Always follow the label instructions, as some pesticides may not be suitable for specific environments.

4.Communication: In managing phorid fly infestations, effective communication with clients is crucial. It is important to educate clients about the persistence of phorid flies and the necessity of eliminating all breeding sources to achieve long-term control. Here are some key aspects to consider when communicating with clients:

1. Persistence of phorid flies: Explain to clients that phorid flies can be persistent pests, especially if breeding sources are not eliminated. Emphasize that simply treating adult flies may provide temporary relief but will not solve the underlying problem. Inform them that the focus should be on locating and eliminating breeding sources to achieve long-lasting control.
2. Management plan: Outline the management plan to address the phorid fly infestation. Clearly explain the steps that will be taken, including inspection, identification of breeding sources, treatment methods, and ongoing monitoring. Provide clients with a timeline and expectations for the control process.
3. Inaccessible breeding sources: In some cases, breeding sources may be challenging to access. Inform clients about such situations and the necessary steps that may need to be taken to eliminate hidden breeding sources. For example, if a breeding source is located under a basement slab, it might require temporarily removing or lifting an area or areas of the floor to access and eliminate the underlying breeding site.
4. Collaboration and cooperation: Stress the importance of collaboration and cooperation between the client and the pest management professional. Encourage clients to follow any instructions provided, such as maintaining proper sanitation, removing potential attractants, and allowing access to necessary areas for inspections and treatments.

5. Monitoring: Use insect light traps to monitor the fly population and assess the effectiveness of the treatment. This helps identify any new introductions and adjust control measures accordingly.

In conclusion, phorid flies can be persistent pests, but with a comprehensive approach that includes proper identification, elimination of breeding sites, targeted treatments, and ongoing monitoring, infestations can be effectively managed.

References:

Disney, R. H. L. (1994). Scuttle Flies: The Phoridae. Chapman & Hall.

Disney, R. H. L. (1991). A key to the British species of Megaselia Rondani (Diptera, Phoridae) with notes on their biology. Field Studies, 7(1), 119-165.