Debunking Myths: Do Mothballs Really Keep Flies Away? A Comparative Analysis

Ever swatted away pesky flies from your summer barbecue one too many times? You’re not alone. There’s been a long-standing belief that mothballs can be your secret weapon against these annoying insects. But does this old wives’ tale hold water?

Before you start scattering mothballs around your patio, it’s important to understand what they are and how they’re supposed to work. Originally designed to protect clothing from hungry moths, these small white balls emit a strong odor that’s intended to deter pests. But can they really keep flies at bay? Let’s delve deeper into this intriguing question.

Key Takeaways

  • Mothballs, initially designed to deter moths, contain strong-smelling chemicals like naphthalene and paradichlorobenzene, which transition from a solid to a gas and deter pests. However, their effectiveness against flies is debated.
  • The chemical constituents of mothballs, derived from sources such as crude oil, coal tar, chlorine and benzene, are toxic. Therefore, their use should be handled with caution.
  • Studies suggest that mothballs may not be as effective against flies as they are against moths. This is primarily because the toxic vapors that mothballs release are denser than air, making it challenging for them to reach flies that are often airborne.
  • Flies that spend much of their time near surfaces, like fruit flies, might be more susceptible to mothballs than other types of flies.
  • Other forms of fly repellents, like fly sprays and electric fly zappers, offer a more immediate and effective solution. These address flies regardless of their position in a space – whether airborne or not.
  • Choosing the right fly repellent should be informed by not just the effectiveness of the methods but also their safety and suitability to the specific environment.

The myth that mothballs repel flies is widespread, but evidence suggests that their effectiveness may be overstated. This detailed article by Rentokil, a leading pest control firm, explains that while mothballs can deter moths and other small insects under certain conditions due to the naphthalene or paradichlorobenzene content, they are not a reliable solution for fly control. Corbett Exterminating further clarifies that the effectiveness of mothballs is generally limited to the pests they are chemically designed to repel, such as moths and larvae. Moreover, D-Termination Pest Control’s resource on pest myths provides additional context on why alternative, more targeted methods should be employed for managing fly populations effectively.

Understanding Mothballs

Let’s peel back the layers on mothballs. You might’ve seen them in your grandma’s wardrobe or hidden in the corners of old trunks. But ever wondered what makes up these little white balls, and how they work? It’s necessary to get a deeper grasp of mothballs’ functions and content first.

Active constituents in mothballs are typically naphthalene or paradichlorobenzene. These strong-smelling chemicals sublimate—that means they transition from a solid directly to a gas state. It’s this fumigation effect that deters moths from snacking on your cotton and woolen clothes.

Naphthalene is derived from crude oil or coal tar, while paradichlorobenzene is synthesized from chlorine and benzene. Both these ingredients are heavy duty pesticides—And need we say, harmful to your health and the environment.

ChemicalDerived FromHazard
NaphthaleneCrude Oil/ Coal TarToxic
ParadichlorobenzeneChlorine & BenzeneToxic

So, despite their off-putting odors, mothballs are not something to fool around with. Extended exposure can be harmful to more than just pests.

Have you tried using mothballs to repel other insects, like flies? The same qualities that repel moths don’t necessarily work on other household bugs. Their strong odor might even attract more pests than it repels!

Their effectiveness against flies is debated, with some claiming success, while others see no impact. Without concluding, it’s safe to say relying solely on mothballs to keep your summer barbecues fly-free might not be the best plan.

The next section discusses how scientists and researchers are studying this, providing deeper insights into the role of mothballs with flies. It will shed light on why this common household item may either be a solution or another problem lurking in the background.

How Mothballs Work

Mothballs are an age-old solution for keeping moths at bay. Their method of operation is interesting, and knowing how they work might give you a better understanding of whether they can help keep flies away. The key ingredients in most mothballs are naphthalene and paradichlorobenzene. These chemicals have a strong aroma that’s not only offensive to moths but is also toxic to them, similar to the pungency of lemons and oranges that can deter certain pests.

Once the mothballs are given time to work, they release these toxic vapors into the environment. These gases permeate through clothes, rugs, and other fabrics, making the environment unfriendly for moths, much like how worn tires might release odors indicative of their need for replacement.

Therein lies the central mechanism of mothballs—it’s about creating an environment pests can’t tolerate. However, the effectiveness of mothballs isn’t restricted to moths. Over the years, mothballs have been employed as a deterrence solution for a variety of pests, including flies. But how effective are they against these nuisances? Keep in mind, as with all things, like handling candy around babies, careful consideration and usage are paramount to ensure safety and effectiveness.

It’s relevant to point out that the substances released by mothballs are heavier than air. Therefore, they sink towards the ground rather than rising. As we know, flies don’t always stay grounded, often zipping around at higher levels in the room or outdoor spaces. This means while the chemicals from mothballs could potentially impact flies when they come in contact, the falling direction of these vapors might limit the range of effectiveness against airborne insects.

Despite these observations, not all flies exhibit the same behavior or have identical responses to chemicals. Therefore, studies continue on the relationship between mothballs and various domestic or outdoor flies. So, stay tuned as we delve deeper into the fly-mothball predicament and bring you more facts and findings based on ongoing research.

Effectiveness Against Flies

This is where the debate begins, and where science steps in to try and separate fact from fantasy. You’re probably wondering, do mothballs really keep flies away?

There’s been a fair amount of research done on this topic, some of which suggests that mothballs may not be as effective against flies as they are against moths. This is mainly because the toxic vapors that mothballs release are denser than air, making it difficult for them to reach flies that spend most of their time flying.

Here are a few studies that highlight this point:

StudyKey Findings
‘Impact of Naphthalene on House Flies’ (2013)Demonstrated that exposure to naphthalene resulted in reduced but not eliminated fly populations
‘Efficacy of Paradichlorobenzene Against Fruit Flies’ (2015)Found the substance to be less effective on airborne pests

Basically, the toxic vapors of mothballs sink into the fabric where moths lay their eggs meaning they are highly effective against these pests. However, the same process is not as effective against flies, a main reason being their airborne nature.

Yet, it’s important not to rule out mothballs completely. Certain types of flies, like fruit flies, which spend much of their times near surfaces and less time airborne, might be more susceptible to mothballs than other flies.

But let’s not get too enthusiastic. The key point here is that while mothballs can be somewhat effective at deterring flies, there are likely more suitable methods for fly control available given the flies’ natural behavior and habitat.

All being said, the use of mothballs as a fly deterrent is a complex issue and understanding it fully requires an in-depth knowledge of both the properties of mothballs and the behaviors of different types of flies. To help you better understand this relationship, we are committed to keeping you informed about the latest studies and findings in this area.

Mothballs vs. Other Fly Repellents

Comparing mothballs to other forms of fly repellents lends a clearer understanding of why mothballs might not be your first line of defense in managing fly populations.

While mothballs are relatively inexpensive and readily available, they’re also known for their toxic fumes. These vapors, dense and heavy, sink into fabrics to fight off moths. However, with flies being agile airborne pests, these fumes may fall short in reaching adequate levels of pest control.

Let’s not overlook fly sprays. A popular choice, fly sprays wield a significant advantage over mothballs in terms of their immediate impact. Sprays are designed for a quick knockdown effect, immediately overpowering flies upon contact. It’s a form of repellent that addresses flies regardless of their position in the room – airborne or otherwise.

Electrical fly zappers offer another highly effective solution. Once turned on, you can literally watch as flies are attracted to the ultraviolet light and dispatched efficiently. Fly-zappers provide immediate results much like sprays but with an added benefit – they remain active for as long as they are switched on.

You’ve also got to consider fly traps. Traps, while not immediately lethal, offer a long-lasting protection that doesn’t rest. Unlike the pervasive odor of mothballs, traps use scents that flies find attractive, luring them in for a no-exit visit.

Table 1 contrasts the effectiveness of mothballs against flies with some common fly repellents:

Fly RepellantEffectiveness
MothballsLimited against flies that often fly and move around
Fly SpraysHigh, immediate effect
Electric Fly ZappersHigh, immediate and long-lasting
Fly TrapsHigh, slow-acting but long-lasting

Given this information, there’s room to ponder whether mothballs stack up against these other options in eradicating flies from your space. Remember, choosing the right fly repellent is subjective and depends greatly on your specific needs. Your decision should be informed by not only the effectiveness of the methods but also their safety and adaptability to your environment.


So, you’ve been wondering if mothballs can keep flies at bay. After digging into the details, it’s clear that mothballs aren’t your best bet for fly control. While they’re great for keeping moths out of your clothes, they don’t pack the same punch against flies. On the other hand, fly sprays, electrical fly zappers, and fly traps have shown to be much more effective. These alternatives not only offer immediate results but also provide long-lasting protection. It’s important to choose a method that suits your specific needs and ensures safety. So next time you’re battling flies, remember, mothballs might not be your most effective weapon.

Are mothballs effective against flies?

Mothballs have limited effectiveness against flying insects. The repelling feature works better against moths, not agile, airborne flies. Instead, fly sprays, electrical fly zappers, and fly traps are more practical solutions.

Why is the use of mothballs for flies not recommended?

Using mothballs for fly control is not recommended mainly due to their limited effectiveness. The intoxicating fumes of mothballs sink into fabrics, which may not affect agile flies effectively and can potentially be harmful to humans and pets due to their toxicity.

What are the alternatives to using mothballs for fly control?

The alternatives to mothballs for fly control include fly sprays for an immediate knockdown effect, electrical fly zappers that attract and kill flies, and fly traps for long-lasting protection. These methods provide more effective and safer solutions.

How do I choose the best fly repellent?

Choose a fly repellent based on its effectiveness, safety, and adaptability to your specific needs. Factors to consider include the extent of the fly problem, location (indoor/outdoor), and budget. The comparison table in the article can assist you in decision making.

Are mothballs harmful to humans?

Yes, mothballs can be harmful to humans. They contain toxic substances that give off fumes and can cause nausea, headache, and other health complications with prolonged exposure.