This is an introduction to a series about 5 common types of drains flies. I will be adding more information on each one over the next month. First never assume that your problem started indoors. Proper identification is necessary in some situations. To identify them you will need to catch one on a piece of tape or any other method that does not destroy what you are going to ID. A magnifying glass and flashlight will help you to get a closer look to make a positive ID.
Some of the flies like to breed on fresh moist decaying matter (fruit, vegetables, moist soil) like fruit and others types may prefer more advanced stages of decay(sewage, dead animals, rotten vegetation). In most cases flying and mating occur more in the evening hours. Under optimum conditions, population growth is explosive.
The only effective method to eliminate them is by removing or treating their breeding sites. Trying bleach, hot water, or ammonia is ineffective because the majority of the larva will still survive. Four of the five drains flies generally (unless you have a break in your sewer line or pipe leaking under the house for examples) do not start from your drains, so early detection of them and removal of their breeding sites may be done immediately to prevent an infestation.
As far as trying to reduce the number of fliers a good fogger or spray with the active ingredient pyrethrin is a great knock down and regarded a generally safe product.
The life cycle of the four types of small filth breeding flies range anywhere from 5 to 25 days. Generally, if you have had them in your establishment 5 days or more indicates that they have already found a breeding site.
In prevention of drain flies it is essential to remove breeding sites immediately to prevent infestation when you first see a couple of any of them. By covering your drains and keeping them covered so they can’t reach this breeding site and removal of other breeding sites for anywhere for a few days will help to ensure that they can’t reproduce in your drains and die off by breaking the life cycle before you get an infestation.
Generally they will startup in either the kitchen or bathroom. A good indication that you have an infestation is when they appear in both rooms and have been around for 5 days or more. Normal process is to treat these areas for 5-7 nights in a row before bedtime while eliminating the other breeding sites at the same time to break their life cycle. The red and dark-eyed fruit flies, moth fly, fungus gnat, and Phorid (humpback or coffin) fly are the 5 most common types of small filth breeding drain flies.
- Red-Eyed fruit fly– Light brown with bright red eyes. They are active fliers and generally start with fruits or vegetables and are attracted to apple cider or balsamic vinegar.
- Dark-eyed fruit fly– Dark colored with dark eyes. They are active fliers and generally start with fruits and vegetables and are attracted to beer, wine, and breads, and moist cat food. More advanced stages of decomposition are preferred than the red-eyed fruit fly.
- Phorid fly– Light brown and humped back no cross veins on their wings and tend to run before they take flight. Prefer advanced stages of decay and could start from outside. A fly sex attractant on a glue stick works well to catch them.
- Dark-Winged Fungus gnat– Tan to dark in color, dark eyes, dark wigs, and mosquito like in appearance. They are active fliers. They generally start with plants and are attracted to the color yellow.
- Moth (Drain) Fly– Brown to black, hairy wings and bodies, roof like wings (not laid back) and are poor fliers. These generally indicate poor drainage or a sewer line break. They leave a leave a powdery residue when squashed. They are attracted to light.
As you can see not all drains flies are treated the same. One thing they all have in common is that in order to eliminate an infestation the key is to remove or treat All of their breeding sites. If the problems still persists after one week then this probably means that all of the breeding sites where not found, improper, incorrect chemical use or the treatment process was not consistent at all breeding sites.
Sanitation and exclusion is your best prevention. Proper identification of what you are dealing with and using the right products in the right areas at the right time is your cure.