Are Lawn Mushrooms Poisonous to Dogs, Cats, or Humans?

Mushrooms have gained something of a reputation throughout the ages. Not only have they been revered in some cultures for their delicious taste and intoxicating effects, they have also been feared for the toxic and even deadly harm they can cause.

Mushroom foraging is an activity that dates back centuries and, these days, has become an increasingly popular pastime. Some of the most common fungi can even be found right in your backyard. However, where there are edible mushrooms, there may also be poisonous ones. 

Many common mushrooms are completely harmless but those that aren’t can have some scary and even fatal side effects. Poisonous mushrooms can grow everywhere that edible ones grow, making them a potential threat to an uneducated forager or their pet. 

Ideally, it’s a good idea to know the difference between edible and poisonous mushrooms but, for the average person, the details of poisonous fungi aren’t always common knowledge. I do, however, have a few basic rules you can follow if you’re unsure about the mushrooms growing in your own lawn, so read on to find out more.

Are Lawn Mushrooms Toxic To Pets?

Dogs and cats are curious creatures, so it’s somewhat common for pets to ingest mushrooms that they come across. Most of the mushrooms that may grow on your lawn are non-toxic but it is always better to approach the situation with caution than to carelessly allow your pet to eat unidentified mushrooms. 

If in doubt, try to avoid allowing your pet to eat any lawn mushrooms you see either by removing them yourself, blocking access to any areas you know mushrooms will be growing, or teaching your dog a command so they know not to eat them.

Toxins found in mushrooms affect dogs and cats in different ways. Some mushroom species emit a fish-like odor which is especially attractive to pets. A pet that has ingested a toxic mushroom will experience a range of symptoms, depending on the variety they have been exposed to.

If you suspect that your pet has ingested a toxic mushroom, you should contact your local emergency vet department or get in contact with someone at the animal poison control service. Try to obtain a sample of the mushroom they have eaten and have it identified by an expert.

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Are Lawn Mushrooms Poisonous To Humans?

It is far more likely that your pet will ingest and become poisoned by a mushroom than you or an adult member of your family will. This is because we are conditioned and have an awareness of the possible dangers of eating an unidentified fungus. However, that’s not to say that this isn’t a possibility.

As with pets, steer clear if you are unsure, clear lawns and trails of mushrooms if you see them growing, and let children and young people know of the potential dangers of eating mushrooms. In my experience, very young children are more likely to ingest strange mushrooms than the average pet and should be closely supervised.

For humans, the ill effects of eating wild mushrooms vary greatly depending on the species, ingester’s body weight, and amount consumed. Symptoms can range from gastrointestinal issues or discomfort, vomiting, headaches, hallucinations, coma, and even (in very rare cases) death. 

If you know or suspect that someone has ingested wild mushrooms, call your doctor, go to the emergency room, or contact Poison Control immediately.

Identifying Potentially Toxic Mushrooms

Of course, you can avoid ingesting poisonous mushrooms altogether if you know what you are looking for. Many harmless mushrooms have poisonous look-a-likes, so understanding the difference between them is crucial. 

The first basic principle is to avoid ingesting any mushroom that you can’t positively identify. This is the case if you have no mushroom foraging experience or even a great deal of knowledge. Here are some common features of poisonous mushrooms: 

  • White gills
  • A ring-like skirt on the stem
  • A volva (a cup-like structure at the base of some mushrooms)
  • Red caps or stems
  • Umbrella-shaped caps
  • Scaly caps

Amanita Fungi

Scaly textures, bulbous bases, red umbrella caps, and white gills are all features of the mushrooms in the Amanita family, which are potentially fatal to both pets and humans.

Amanita mushrooms have dry and scaly caps that stand out from other varieties of mushrooms. 

Amanita mushroom
Amanita Mushrooms

Another way to potentially identify poisonous mushrooms is to apply pressure to the cap. For example, poisonous Amanita mushrooms develop red bruises when damaged or broken. 

If you are still unsure if you have poisonous mushrooms on your lawn, especially Amanita mushrooms, you can cut the stem and do what’s called a spore print. To do this, cut the mushroom cap off and place it gill-side down onto a piece of dark-colored paper.

If you have an Amanita mushroom, there will be a white outline on the paper within a few hours. Always wear protective clothing and gloves when handling mushrooms and avoid ingesting, getting on skin, or rubbing eyes after touching them.

Identifying Look-A-Like Mushrooms

Several types of edible lawn mushrooms have poisonous look-alikes. Morels and false morels, chanterelles and jack o’lantern mushrooms, and honey mushrooms and Galerina mushrooms are all examples of these potentially deadly pairings. 

To tell a morel from a false morel, examine the cap and stem. A real morel is hollow inside of the cap, while a false morel’s cap looks almost like cotton on the inside. 

To tell the difference between an edible chanterelle and a deadly jack o’lantern mushroom, check the gills. Chanterelle mushrooms have false gills that are inseparable from the cap, while jack o’lanterns have true, jagged gills. 

The best way to tell the difference between honey mushrooms and Galerina mushrooms is to take a spore print. Honey mushrooms will produce a white spore print, while Galerinas will make a brown spore print. 

Even experienced foragers can misidentify fungi. If you’re interested in foraging for edible mushrooms — even if your chosen variety lacks any close look-a-likes — I highly suggest working with a very experienced forager and using multiple identifiers before settling on a positive ID.

Symptoms Of Mushroom Poisoning

Symptoms of mushroom poisoning will vary from one variety of fungus to another. Symptoms will also vary in severity from humans and pets and depending on how heavy the person or pet is and how much they have ingested.

Symptoms In Dogs

Mushroom poisoning in dogs can result in symptoms as mild as an upset stomach or as extreme as death. Some of the most common symptoms to watch out for if you believe that your dog has ingested toxic mushrooms are: 

  • Diarrhea
  • Vomiting
  • Weakness
  • Inability to wake
  • Tremors
  • Loss of coordination
  • Abnormal vocalizations 
  • Sleepiness
  • Coma

If you suspect that your dog has ingested a poisonous mushroom, contact the emergency vet department or poison control for pets right away. While some dogs may exhibit symptoms right away, others may take days. 

One of the most devastating effects that mushroom toxicity has on dogs is coma induction. Many toxic mushrooms will put your dog in a coma-like sleep that can be difficult or impossible to wake from. 

Symptoms In Cats

Mushroom toxicity in cats has many different forms. Many cats love the fishy odor of Amanita mushrooms, so it’s crucial to keep a close eye on your cat if allowed out during the fall and early winter when these mushrooms typically grow naturally. 

Some of the most common symptoms of mushroom toxicity in cats to look for are:

  • Diarrhea
  • Vomiting
  • Dilated pupils
  • Increased body temperature
  • Lethargy
  • Tremors
  • Increased grooming
  • Inability to wake

If you suspect that your cat has ingested toxic mushrooms, you should contact an emergency vet or poison control for pets immediately. 

Symptoms In Humans

Humans can be more resilient when it comes to mushroom poisoning than animals are. This is mostly because the average person is larger than the average pet. For this reason, however, children are more susceptible to serious symptoms.

For the most part, humans will experience gastrointestinal discomfort that usually goes away within a few days. Some of the more detrimental symptoms of mushroom poisoning include:

  • Hallucinations
  • Liver failure
  • Kidney failure
  • Dizziness
  • Fever
  • Seizures 

If you’ve ingested a mushroom and are experiencing side effects, contact the emergency department or poison control immediately to get help. 

Mushroom Poisoning Treatments

After mushroom poisoning is diagnosed, it’s crucial to begin treatment immediately. For both pets and humans, the first course of action is usually stomach pumping or gut irrigation. This can help rid the body of toxins before they’ve had the chance to absorb them into the bloodstream. 

Despite common beliefs, please DO NOT ingest vomiting in a cat or dog without veterinary oversight. You can easily do more harm than good.

What Causes Mushrooms To Grow In Grass?

Mushrooms are most commonly seen growing in the wild between September and November. This is when temperatures begin to drop a little but before any heavy frosts that the winter months can bring. They prefer slightly warmer as well as damp conditions in order to thrive. 

According to the University of New Hampshire, one of the key factors contributing to mushroom growth is a prolonged rainy season. During these long periods of damp and humid conditions, the fungus produces fruiting bodies that grow to produce spores that travel to grow other fruiting bodies. 

Mushrooms thrive on soil with heavy amounts of organic material present, so lawns with rich soil are more susceptible to mushroom growth. Poor soil drainage is also another contributing factor. 

How To Get Rid Of Lawn Mushrooms

What many people don’t know about mushrooms is that the fungus that produces the fruiting bodies can live in the soil for a year or more waiting for the perfect conditions to grow. Therefore, getting rid of mushrooms in your lawn before they sprout is essential to prevent them from being accidentally ingested. 

Some of the most common ways to get rid of lawn mushrooms include fungicides, vinegar, baking soda, and regular maintenance. 

Fungicide

Fungicides are pesticides designed specifically to target fungus and mushroom growth. Fungicides damage fungal cell growth and inhibit enzyme production. 

Fungicides take an average of 7 to 10 days to work but they can remain in the soil for up to a month. To apply a fungicide to your yard, follow the directions on the packaging. 

Vinegar

The active ingredient in vinegar is acetic acid. Acetic acid is a powerful non-toxic herbicide that enters a cell’s membrane and disrupts cell function, inhibiting enzyme production, which kills the fungus. 

You can use regular household vinegar, or you can purchase a stronger acetic acid concentration pesticide. Applying a vinegar solution as a fungicide to your yard is very easy to do. All you need to do is put the vinegar into a sprayer and spray the affected area. 

Just bear in mind that vinegar is non-selective and will kill everything it comes into contact with, so avoid using this on lawns you wish to preserve. For best results, you should avoid doing this when there is rain in the forecast so that the vinegar can seep into the soil and achieve the maximum desired effect.

Baking Soda

Baking soda is another non-toxic fungicide. Baking soda essentially dries out the soil, which discourages fungus growth. Baking soda can also kill current fungal growth by drying out its cells. 

To use baking soda as a fungicide, sprinkle it over the affected area and allow it to sit for a few days. This method works best when there is no rain in the forecast so that the baking soda has time to fully dry the mushroom out. 

Applying baking soda to your lawn can also help prevent further mushroom growth from occurring since it will help dry out your soil. Again, bear in mind that baking soda will also cause harm to your lawn so you may need to select a selective fungicide to avoid lawn damage.

Avoid Overwatering Your Lawn

The best way to stop poisonous mushrooms from growing on your lawn is to prevent them from ever growing in the first place. Because garden mushrooms thrive in warm and wet conditions, over-watering your yard can encourage fungus growth. 

By avoiding over-watering your lawn, you are discouraging any fungal spores present in your soil from sprouting. After so long, these spores will eventually die in the soil if their conditions for growth aren’t met. 

Dethatch, Aerate, and Fertilize

In addition to wet conditions, mushrooms thrive in soil that is rich in organic matter. To discourage mushroom growth in your lawn, it is crucial to regularly dispatch, aerate, and fertilize your lawn to encourage healthy plant growth. 

Dethatching and aerating your lawn breaks up the organic matter and creates a less appealing environment for fungus growth. When you apply fertilizer after aerating your lawn, you are encouraging healthy plants to grow, causing competition in the soil. Many fertilizers contain a fungicide that will also help to prevent the growth of mushrooms in your lawn.

Frequently Asked Questions

Final Thoughts On Lawn Mushroom Safety

Unless you are an expert, determining the difference between edible and poisonous mushrooms is a risky game with little reward. Lawn mushrooms can be just as poisonous as any other mushrooms, so avoiding them is the safest option. If you or your pet accidentally ingest a toxic mushroom, seek medical help immediately.