Are Flies Attracted to Mold? Understanding the Connection

More and more people are becoming aware of how dangerous mold can be in homes, offices, and other indoor places. Not only does so-called “Toxic Black Mold” harm your health and lungs, but even less dangerous molds that live in the air can cause a wide range of health problems. This is especially true for people who have respiratory allergies, long-term lung conditions, or genes that make them more likely to have chronic inflammation.

Sometimes an indoor mold problem is obvious. In damp, wet parts of your home, you may see spots that are black, gray, or other colors; in a crawl space in your basement, you may smell something earthy. Though there are certainly other times when a mold problem can be hard to detect without professional diagnostics. Especially if the mold has grown in your walls or other places that are hard to see.

Phorid flies, sewer flies, or other gnats or bugs in your home or office could be a sign that you don’t know about a mold problem.

Finding flies hovering around mold growth in your home can be concerning. It’s natural to wonder – are flies actually attracted to mold? What causes this relationship between flies and mold? Let’s take a closer look at why these pesky insects gather around mold.

An Overview of Flies and Mold

  • Mold refers to fungi that grow in warm, damp environments indoors and outdoors. Different mold species exist.

  • Flies are insects with two wings that go through complete metamorphosis. Many fly species exist.

  • Certain flies are drawn to the dampness, rotting odors, and food source found in mold.

  • Mold creates ideal breeding conditions for flies by providing food and moisture.

  • The most common flies attracted to mold are fungus gnats, moth flies, fruit flies, and phorid flies.

  • Getting rid of mold removes the developmental environment for flies and breaks the attraction cycle

Why Are Flies Drawn to Mold?

There are a few key reasons flies seek out mold

Moisture Source

  • Flies need moisture to complete their life cycle. Mold indicates a damp area where flies can lay eggs.

Food Source

  • Some flies directly feed on mold as a food source. Their larvae eat decaying organic matter.

  • Mold breaks down materials, creating rotten food attractive to flies.

Organic Scent

  • Flies detect the musty, earthy odor molecules released by mold growth. They are attracted to these scents.

Shelter

  • Dense mold provides flies with protection and a place to safely reproduce.

Common Fly Species Associated with Mold

While many flies may occasionally visit moldy areas, these are the main species with a strong attraction to mold:

Fungus Gnats

Tiny black flies drawn to moist potting soil and rotting plant matter. Their larvae feed on fungi.

Moth Flies

Known for hovering near drains, moth flies breed in damp slime and sewage.

Fruit Flies

Tiny flies that lay eggs on ripening produce and vegetables, attracted to mold and fermentation.

Phorid Flies

A small fly that deposits eggs in damp decaying materials, fungi, and sewers.

Health Risks of Flies and Mold

The combination of flies and mold poses potential health hazards:

  • Flies transfer mold spores to surfaces, spreading allergens.

  • Breeding flies indicate high levels of fungus, raising allergy and asthma risks.

  • Flies can transmit bacteria picked up from garbage and fecal matter.

  • Mold exposure is linked to respiratory issues, headaches, fatigue and more in sensitive individuals.

  • Flies regurgitate on food as they eat, contaminating surfaces.

How to Get Rid of Flies in Moldy Areas

To clear up flies in moldy parts of your home:

Fix Moisture Issues

Eliminate leaks, improve ventilation and reduce humidity. Drying up mold removes the fly habitat.

Clean or Remove Moldy Items

Clean off non-porous surfaces with detergent and water. Porous materials may need disposal.

Use Fly Traps and Baits

Fly traps capture adult flies. Baits poison larvae but won’t combat mold.

Apply Pesticide Sprays

Insecticide sprays kill flies on contact but won’t provide ongoing prevention.

Seek Professional Help

For large infestations, professional exterminators employ the latest pest solutions.

Prevent Access to Food

Store food sealed and dispose of ripe produce to avoid attracting fruit flies.

Maintaining a Mold and Fly-Free Home

Prevention is the best long-term solution to keep flies away from mold:

  • Allow ventilation for moisture control and dry out wet spots quickly.

  • Fix plumbing leaks right away to avoid moisture buildup.

  • Clean fruits and vegetables immediately, storing produce properly.

  • Take out trash regularly before odors develop.

  • Keep surfaces free from dust, dirt and grime where flies can breed.

  • Install screens on windows and doors to block flies entering the home.

With vigilance, you can maintain a home free from both flies and mold!

The Phorid Fly Lifecycle

Unfortunately, phorid flies are also very good at quickly establishing a presence in indoor spaces. Often, this is because female phorid flies can lay up to 40 eggs that will hatch in just 12 hours. After being laid, the eggs can hatch into larvae in as little as one day. Female phorid flies can also lay about 500 eggs.

Phorid fly larvae develop fastest in the presence of moist conditions with decomposing organic matter nearby. This includes things like fermenting fruits, garbage containers, rotten vegetables, improperly stored meats. Even some organic glues and paints made from natural materials can be good places for a lot of phorid fly larvae to lay their eggs.

These basically give the young phorid flies the food and water they need to become adults in as little as 14 days. Though cool, dry conditions can slow the larval maturation process to nearly 40 days. So, the speed with which an indoor phorid fly infestation grows can also show you if your walls are wet or if there are other problems in your home.

How Can Phorid Flies Be A Sign Of Mold?

Because they are smart and persistent, phorid flies are likely to show up in your home sometimes. It’s when you start seeing them frequently and in increasing numbers that you should be concerned about. Especially if they start to gather quickly in damp places like the bathroom, laundry room, basement crawl space, or areas close to the “Wet Wall” that holds your home’s main plumbing pipes.

How To Deal With Fruit Flies And Drain Flies

FAQ

Why are flies attracted to mold?

Not only do they feed on the mould itself, but they also use the dampness as an ideal place to breed and lay eggs. Rodents, flies, moths and even cockroaches are all attracted to moist environments, so it’s important that you take steps to remove any mould before it gets out of control.

Can mold create flies?

The answer is yes. Rot, mold, and associated moisture in storage spaces will attract fruit flies. Empty and clean your storage spaces regularly. Transfer your food to airtight plastic containers to deter fruit flies and other pests.

What do mold flies look like?

Chances are you’ve even seen them before. They look like tiny flies that are roughly in between the size of a common black house fly and an annoying fruit fly. They look like a slightly larger fruit fly, without the telltale red eyes.

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