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Common Molds and other Contaminants of Mushroom Cultures to help you identify what you are dealing with

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Trichoderma or as I like to call it "Emerald Death" is a very common aggressive Mold that no Mushroom Cultivator wants to deal with.
It has ruined countless Mushroom Grows for many People and likes to contaminate your Grow Area with Spores.
The early Mycelium Stage of Trichoderma is often Light Grey in Color and not always easy to spot.
Likely the Contamination will first appear as a thick, white fluffy Patch on top of your Substrate.
Trichoderma Spores produce a yellowish to greenish Mycelium that often has a bright white Ring surrounding it.
Contamination with Trichoderma can happen at all stages and it is very hard to get rid off once it produces Spores.
Smell Testing can help you spot Trichoderma early. It smells a little bit like Coconut but not all Trichoderma Strains have a distinct Smell.
Fighting Trichoderma is often a lost Cause but many People have reported that burning it with Fire slows it down
enough for your Grow to produce at least one more Flush.


Also known as Green Mold or Blue Mold Penicillium is a very common Fungus with Spores everywhere in the Air.
These Fungi are one of the biggest Concerns for Mushroom Cultivators working with Agar and Grain Cultures.
Penicillium Contamination starts out with white Mycelium which makes it hard to distinguish from normal Mushroom Mycelium.
By the Time it produces colorful Spores on top of the Substrate the Penicillium Mycelium usually buried itself deep into the Substrate.
Penicillium is very agressive. It spreads very quickly and can take over other Mushroom Mycelium within Days.
Colonies of Penicillium are usually circular in Shape and can often be found on Wood, so it is advised not to use wooden Trays.
Penicillium usually only affects uncolonized Grains or Agar and is rarely seen after the Spawning Stage.
It has a musty Smell that resembles Dirt.


Aspergillus Mold is a very common Fungus that is everywhere in the Air and survives on many Surfaces.
Because of this it is very easy to contaminate your Mushroom Grow with an Aspergillus Strain.
Aspergillus Mycelium is usually light-gray and hard to tell apart from your normal Mushroom Mycelium.
Different Aspergillus Strains produce different kinds of Spore Colors like Black, Brown, Yellow or even Green and Blue.
Colonies of Aspergillus sometimes form a Ring of dense Mycelium at the Edge and often have a musty and oily Smell.
You can try to fight Aspergillus by spraying it with a Hydrogen Peroxide (H2O2) Solution.


Cobweb Mold looks like fluffy cottony Mycelium that completely covers your Substrate and softly envelops your Mushrooms.

This Fungus is just a little bit darker than your regular Mycelium and can be very hard to identify without Experience.

Cobweb Mold starts as a little Patch and grows explosively fast covering your whole Casing Layer within one or two Days.
Stale Air and high Humidity Levels attract Cobweb Mold so make sure to increase Air Circulation and Air Exchange regularly.

You can try to fight Contamination with Cobweb Mold by spraying it with a Hydrogen Peroxide (H2O2) Solution.


Also known as Pin Mold or Pinhead Mold Rhizopus is a very fast growing Fungus that develops small black Pinheads to release Spores.
Rhizopus loves to grow in Places where there are plenty of Carbohydrates (CO2) readily available for Consumption.
It is commonly found in Straw but old Fruits or old Grain is also not safe from Rhizopus. Grain Spawn is a perfect Place for it.
Rhizopus Contamination is rarely found after the Spawn Stage, but if you do, you can fight it with a Hydrogen Peroxide (H2O2) Solution.


Lipstick Mold is a Fungus that loves to colonize Compost and Casing Layers feeding on Fats.
It grows very slowly and the Spores have a Pink, Red and sometimes even Orange Color.
Spores of the Lipstick Mold are realeased into the Air when the Culture comes in Contact with Water.
It is very uncommon and Contamination can easily be avoided by keeping your Growing Area clean.
You can try to fight Lipstick Mold by spraying it with a Hydrogen Peroxide (H2O2) Solution.


Also known as Red Bread Mold or Pink Mold Neurospora is a very resilient and fast growing Contaminant.
It is commonly seen on Grain and Agar in Mushroom Cultivation and on Dung, Soils and dead Plant Matter in free Nature.
Neurospora can grow right through Filters so a single contaminated sealed Jar can contaminate your whole Area.
The Pink Mold Variant of Neurospora is especially hard to eliminate and should be disposed of immediately.
After the Disposal of contaminated Cultures a thorough Cleaning of your Grow Area is 100% necessary or it will come back.
Neurospora Contamination is definitely not a Joke.


Verticillium is the Fungus that causes the so called Dry Bubble Disease infecting the Fruit Bodies of a Mushroom Grow.
Depending on the Stage the Mushrooms are in when catching the Dry Bubble Disease the Symptoms can vary.
Verticillium Infections in the Pin Stage can lead to Deformations, a Grey or Brown Discoloration and even Aborts.
Infections at a more mature Stage can lead to a very thick Mushroom Base and bizarre crooked Deformations.
Verticillium produces sticky Spores that latch on to Dust, Dirt and Insects.
For this Reason you should avoid using a Vacuum Cleaner near your Grow which swirls up a lot of Dust.


Otherwise known as Sour Rot or Wet Spot Bacillus will make your Grain look excessively wet.
It looks like a Grey or Brown Slime and smells of rotten Apples or dirty Socks and sometimes even like burnt Bacon.
Bacillus can provide a strong defensive Shell for itself when facing harsh Environments over long Periods.
For this Reason it often survives the Heat Sterilization of your Grain and other Methods of Decontamination.
To counter this, soak your Grain for 24 Hours before sterilizing. This way the Bacillus lowers the Defense and is killable.


Bacterial Blotch can be identified by Yellow to Brown Spots at the Edge of the Caps that look like Injuries.
It is caused by excess Amounts of Water on the Mushrooms over long Periods of Time.
If Bacterial Blotch remains uncontrolled it will develop a watery Slime on the Mushroom Caps.
It will also cause a faster Deterioration of the Mushrooms after Harvest.
Measures of avoiding Bacterial Blotch involve a clean Environment and not spraying the Mushrooms with Water directly.
Bacterial Blotch is 100% safe to eat and only lowers the perceived Quality of especially Gourmet Mushrooms.
You can fight Bacterial Blotch by spraying it with a 15% Chlorine Solution.


Overlay or Stroma otherwise known as Mycelium Scar Tissue or Aerial Mycelium is actually not a Contamination but will prevent Growth.
It is caused by an overcolonized Casing Layer that has been exposed to high Temperatures or high CO2 Levels for way too long.
Stroma can be identified by thick smooth Mycelium Layers on top of the Substrate that are watertight.
This watertight Overlay prevents the Mycelium from hydrating and pinning. It will even abort existing Pins.
You can try to scratch it off the Surface and rehydrate the Myelium Cake but Chances for Recovery are slim.
To prevent Overlay or Stroma, put your Colony into Fruiting Conditions at the right Time and provide regular fresh Air Exchanges.

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