Artillery fungus is a common nuisance mold found outdoors that can leave tiny black spots on houses, cars, patio furniture, and other surfaces. Learning how to identify artillery fungus and prevent its spread can help homeowners minimize the annoying black specks caused by this mold.
What Is Artillery Fungus?
Artillery fungus, also known as shotgun fungus, is a type of saprophytic fungus that gets its name from the way it shoots its spores out into the air. The fungus goes through a life cycle that allows it to fling out these sticky spores up to several meters away from its original location. When the spores land on a surface, they leave small black dots, usually around 1mm wide.
This fungus thrives outdoors in mulch, soil, and decaying matter. It needs moisture and organic material to grow. The spores tend to be dispersed more during wet weather. When the blackened spores accumulate on outdoor surfaces, it results in the appearance of tiny black speckles on siding, cars, outdoor furniture, etc, often called artillery fungus black spots.
While annoying, artillery fungus spores are not harmful to human health. The black spots are just a cosmetic nuisance. However, they can potentially damage some materials over time if left to accumulate, and they are difficult to remove from porous surfaces. So it’s useful to know how to recognize and manage artillery fungus.
Identifying Artillery Fungus
Learning how to identify artillery fungus damage is the first step in prevention and treatment. Here are the key signs that point to artillery fungus as the cause of tiny black spots on your home or belongings:
Small Round Black Spots
The most telltale sign of artillery fungus is the appearance of small, round black spots, usually around 1mm in diameter. They will appear scattered in a speckled pattern, not in large continuous stains. The small size and shape of the dots distinguish them from other types of black mold.
Mainly on Outdoor Horizontal Surfaces
Artillery fungus spores will be most noticeable on outdoor horizontal surfaces such as roofs, decks, siding, and cars. The spores shoot out from the ground so they tend to land on surfaces that face downward. The spots will be especially concentrated on surfaces closest to mulched areas.
Spots Difficult to Remove
The black artillery fungus dots often adhere quite stubbornly to surfaces and can be hard to scrub off. Unlike surface dirt, they will not just hose off easily. This resistance to removal is because they contain pigments that can stain.
Worsens in Wet Weather
Artillery fungus thrives in moist conditions. Its spores tend to be spread in largest amounts during spring and summer rainy periods. Downpours will lead to an increase in dots appearing on outdoor surfaces.
May Slowly Damage Material Over Time
Although not a hazard to health, artillery fungus spores can potentially degrade certain materials if allowed to accumulate for years. For example, some types of vinyl siding may become brittle and crack. Keeping surfaces clean prevents buildup.
If your home is plagued by difficult-to-remove black spots that display these characteristics, artillery fungus is most likely the culprit. Examining the spots under magnification can also reveal the characteristic shape and texture of the fungal spores.
Where Does Artillery Fungus Come From?
Artillery fungus originates in the soil and organic materials outdoors. Some key sources that encourage artillery fungus growth include:
Mulch
Mulch provides an ideal environment for artillery fungus. The decomposing wood supplies nutrition, while the moisture retention nurtures growth. Artillery fungus sends out runners through mulch, multiplying. Its spores then get kicked up from the mulch onto nearby surfaces. Keeping mulch fresh can help reduce artillery fungus.
Leaf Piles
Leaf litter offers another favorable place for artillery fungus to thrive. The fungus will grow on decaying leaves. Raking up and removing leaves eliminates this reservoir.
Rotting Logs
Old rotting logs or stumps can harbor colonies of artillery fungus. Again, the decomposing wood feeds the fungus. Removing or replacing any rotting logs can impede the mold.
Soil
Nutrients in soil also allow artillery fungus growth. Good lawn care and avoiding over-watering reduces fungus-friendly conditions. Using lime or fungicides on soil may help.
To control the overall source, reducing moist organic matter where the fungus can grow is key. Proper mulch care, lawn care, and yard cleanup will reduce reservoirs.
How Does Artillery Fungus Spread?
Understanding how artillery fungus propagates can help guide prevention methods. This fungus has an ingenious mechanism that allows it to fling spores long distances. Here is how it spreads:
Growth Phase
During moist conditions, the threadlike mycelium of the artillery fungus grows through soil and mulch, extracting nutrients needed to produce spores. The mycelium can extend away from the main mass.
Builds Pressure
In bulbous areas of mycelium, pressure builds up from the release of sugars and carbohydrates. This pressurized area morphs into a round sac filled with spores in fluid, called a peridiole.
Sudden Release
When mature, the peridiole ruptures at a weak point at the top, launching the liquid contents into the air in a sudden burst. The popping sound led to the “artillery” name.
Spores Travel Far
The droplets expelled from the peridiole get dispersed over a wide area due to the pressure impulse. Spores may travel up to 10 meters horizontally. The popping action also gave rise to the name “shotgun fungus”.
Spots Appear
Wherever the droplets land on surfaces, the spores stick and germinate, producing pigments. These pigments stain surfaces with small black round spots – the telltale signs of artillery fungus.
Understanding this dispersal method helps guide prevention. Reducing moisture and nutrient sources disrupts the fungal life cycle. Careful aiming of landscape sprinklers also reduces spread.
How to Remove Artillery Fungus Spots
Once artillery fungus has already created spots, removing the black specks can be challenging. Here are some methods to try:
Daily Power Washing
For heavy spot buildup on house siding or decks, power washing daily may eventually remove artillery fungus stains. It takes persistence to break down the pigments.
Bleach or Peroxide
Applying diluted bleach or peroxide solutions directly to the spots can lighten them over time through several treatments. This works best for non-porous surfaces.
Repainting or Re-staining
On surfaces like wood or composite decks, refinishing with stains or paints provides a new covering that hides old fungus spots. This is often the most effective remedy for porous surfaces.
Replace Mulch Regularly
By replacing mulch annually, you remove the food source before substantial spore buildup. Fresh mulch will stay fungus-free longer.
Clean Cars Frequently
Frequent washing removes spores from car paint before they bond and stain. Waxing also makes car paint slicker so spores wash off easier.
Though difficult to remove entirely once settled in, staying vigilant by frequently cleaning or refinishing surfaces can help control artillery fungus spots. Avoiding buildup is most effective.
How to Prevent Artillery Fungus
Preventing artillery fungus from taking hold in the first place is the best approach. Here are some key prevention tips:
Allow Surfaces to Dry Out
Keeping outdoor surfaces drier denies artillery fungus the moisture it relies on. Letting the sun fully dry out decks and roofs discourages spore spread and growth.
Direct Sprinklers Away
Adjust sprinkler directions so water doesn’t directly soak siding and structures. This reduces spore dispersal and conditions for fungus growth on surfaces.
Replace Mulch Regularly
Replacing mulch annually or biannually eliminates older mulch where fungi flourish. Fresh mulch resists fungus for longer.
Remove Leaf Litter
Rake up and dispose of leaf litter to avoid moist organic buildup where fungus can grow. Removing fallen leaves starves the fungus.
Apply Fungicidal Products
Applying fungicidal sprays or powders onto mulch and soil can inhibit artillery fungus at the root. Products with chlorothalonil are effective.
Allow Air Circulation
Promoting air flow around structures leaves less surface moisture for fungi. Proper pruning opens up air flow.
Clean Gutters
Keeping gutters clear prevents moisture buildup that drips fungus-feeding organic matter near foundations.
Repeat applications of fungicides or sodium chloride may also suppress artillery fungus growth on soil. For severe cases, excavating and replacing the soil removes the spore source.
How to Get Rid of Artillery Fungus in Mulch
Mulch is the most common source of artillery fungus. To eliminate fungus from mulch beds:
- Remove old mulch completely and replace with fresh mulch. Discard old mulch away from property.
- Before installing new mulch, spray soil with fungicide like copper sulfate.
- When adding new mulch, mix in fungicidal powder labeled for mulch.
- Use less organic mulch near foundations, more rock or gravel instead.
- Maintain 2-3 inch mulch depth, no more. Excessive depth holds moisture.
- Rake mulch frequently to aerate and check for fungus.
- During wet months, sprinkle mulch with baking soda, borax or lime.
Replace mulch at least once a year. Removing the food source interrupts the fungus lifecycle.
With vigilance to limit moisture and food supply, artillery fungus can be controlled. A dry environment and fungicide treatments restrict growth both on surfaces and at the soil source. Through prevention and reduction of fungal habitats, artillery fungus spots can be minimized.
Frequently Asked Questions About Artillery Fungus
Does artillery fungus go away on its own?
No, artillery fungus does not disappear by itself. Once it has established itself in an environment, especially in mulch or soil, it will continuously spread spores during moist conditions. To get rid of artillery fungus, moisture sources must be reduced, spores scrubbed from surfaces, and fungicidal products applied.
Does artillery fungus spread to lawns?
Artillery fungus prefers mulch and woody materials to lawns. It relies on the nutrients in decaying organic matter more than live grass. So lawns are rarely affected, though fungus may grow in thick thatch buildup. Proper lawn aeration reduces chances of fungus growth.
Is artillery fungus harmful to pets?
Artillery fungus does not pose any health hazards to pets. Dogs and cats may pick up spores on their fur, tracking the black dots indoors, but the spores will not harm them if licked or ingested. The fungus can be an irritant to pets if it colonizes mulch where they frequent.
Can you prevent artillery fungus?
Yes, taking proactive prevention measures can help avoid artillery fungus or limit its severity. Removing conducive conditions before fungus takes hold is the best approach. This includes proper mulch care, pruning for air flow, fungicide use, and directing water away from structures.
Will replacing mulch get rid of artillery fungus?
Replacing all of the mulch can eliminate artillery fungus, but only temporarily. Spores may still remain in the soil or adjacent areas, and eventually spread back into new mulch. Combining new mulch with fungicidal soil treatment provides more long-lasting prevention. Annual mulch replacement is recommended.
Conclusion
Dealing with artillery fungus can be frustrating given the difficulty in eradicating its stubborn black spots. However diligent prevention and control practices can help minimize the annoying spore speckles. Reducing moisture sources, frequent cleaning, fungicide applications, and replacing fungus-prone mulch and materials can significantly reduce artillery fungus problems. With proper identification and knowledge of its growth habits, artillery fungus can be managed for cleaner outdoor living spaces. Implementing preventive measures is the best tactic against this nuisance fungus.