A Beautiful Mushroom… but One That Needs to Be Known Thoroughly

In recent years, the Golden Oyster (Pleurotus citrinopileatus) has become one of the most popular gourmet mushrooms. Its bright yellow color, rapid growth, and delicate aroma have made it a favorite among mushroom growers.

But as often happens in nature, even beauty can have a downside. Recent studies conducted in the United States are raising an important question: can this fungus, introduced from East Asia, adapt and reproduce in natural environments outside of cultivated areas?

Origin and Spread of the Golden Oyster

The golden oyster mushroom is native to eastern Russia, China, and Japan. It belongs to the Pleurotus genus, the same as the common oyster mushroom ( Pleurotus ostreatus ), but is distinguished by its golden cap and greater resistance to high temperatures.

Since the 2000s, the Golden Oyster has been introduced to Europe and North America for commercial purposes: easy to grow, scenic, and very profitable.

In Italy, however, many large cultivation companies market this species under the incorrect name of Pleurotus cornucopiae , a species that is actually native to our country.

This can be confusing, as in most cases it is actually Pleurotus citrinopileatus — the true “Golden Oyster” of Asian origin — and not the European P. cornucopiae .

What Does “Invasive” Mean for a Fungus?

When we think of invasive species, our minds immediately turn to plants or animals, but fungi can also colonize new environments unexpectedly. In ecology, there are three categories:

• Introduced species: brought by humans to a new territory.
• Naturalized species: it is able to reproduce spontaneously in the new environment.
• Invasive species: it spreads actively, competing with native species.

In the case of the Golden Oyster, some field observations indicate that in certain areas of the United States the fungus is fruiting spontaneously on logs and dead wood in natural environments, far from the crops from which it originated.

First Reports in North America

In recent years, American researchers have documented the presence of the Golden Oyster in the wild.

A recent study conducted by the University of Wisconsin–Madison has highlighted that the presence of this fungus in Wisconsin forests can have negative effects on local biodiversity .

Analyses carried out on logs colonised by Golden Oyster show a profound alteration of the fungal communities inhabiting the wood and a significant reduction in species diversity .

What does it mean?

That when the Golden Oyster mushroom establishes itself in a natural ecosystem, it alters the ecological balance of the forest and can contribute, over time, to the local disappearance of native fungal species .

Source: Veerabahu et al. Invasive golden oyster mushrooms are disrupting native fungal communities as they spread throughout North America. (2025)

The Situation in Italy

Currently, there are no studies exploring the presence of Golden Oysters in Italy or the rest of the European Union. It is not yet clear whether this species is naturalized in Italy. However, there are observations reported on the iNaturalist platform, which could indicate a possible presence of these species in natural environments. Most observations in Europe appear to be in Italy.

During a direct discussion with Aishwarya Veerabahu, a researcher from the University of Wisconsin-Madison , we were informed that preliminary distribution models of the species show that most of Europe — with the exception of the north-eastern areas, including Finland and Russia — and especially the Italian peninsula , has climatic conditions favorable to the establishment of the Golden Oyster.

These studies are a wake-up call: if an introduced species is able to reproduce autonomously, it means it can interact with local fungal communities and, over time, modify them.

The Ecological Risk

It is important to be clear: the Golden Oyster is not yet recognized as an invasive species , but it is a species that should be monitored carefully .

Its spread, if it were to begin, could be rapid and unpredictable , with trajectories that are difficult to anticipate.

Potential risks include:

• Competition with other native species and local decomposers.
• Alterations in wood decomposition cycles and carbon emissions
• Extinction of native species
• Alteration of native fungal communities and forest ecosystems.
  
• Reduction of biodiversity of species related to deadwood.
  

To date, no control strategy is available.

Cultivate Responsibly

Being a farmer today also means being a custodian of biodiversity.

The industry's responsibility is not only to produce quality mushrooms, but also to protect the ecosystems around us. Therefore, as a cultivation company, Growers of Mushroom declares that:

"Having assessed the evidence currently available on the risk of invasion in Italy and the possible environmental damage that may result, as a company we will stop selling crops, grain spawn and cultivation kits of Golden Oyster ( Pleurotus citrinopileatus ) . This will stop and prevent us from further contributing to the release of spores of this species into the environment.

We invite all mushroom growers in Italy to remove P. citrinopileatus and P. cornucopiae from their production and to join in raising awareness of this issue.

In addition to doing this, we decided to create an observatory to collect data regarding the presence of P. citrinopileatus in the ecosystems of our peninsula."

The Project: The Citrinopileatus Observatory

To contribute concretely to the knowledge and management of this species, Growers of Mushroom has launched the Citrinopileatus Observatory , the first Italian data collection project dedicated exclusively to this mushroom.

The goal is:

• Collect and verify reports of possible presences in nature.
• Collaborate with researchers who are studying the phenomenon internationally.
• Raise awareness in the cultivation sector towards more sustainable practices.

👉 Join the Golden Oyster Observatory
Contribute by submitting photos, coordinates, and direct observations. All collected data will be sent to researchers analyzing the species' distribution in the wild.

Conclusion – Cultivating Awareness, Not Just Mushrooms

The Golden Oyster is a marvel of nature: elegant, productive and delicious.
But the time has come, as growers, to take responsibility for growing with ecological awareness.
We are, first and foremost, nature lovers and guardians of these organisms that offer us so much—the same fungi that make our work possible and that deserve to be respected and protected.

What can you do as a Farmer?

• Choose species native to your area, preferably with local genetics.
• Avoid the dispersion of spores: use sterile strains or collect mushrooms before they begin to sporulate (e.g. Reishi).
• Educate your community and customers about the environmental risks of invasive species.
• Involve everyone in the Citrinopileatus Observatory project, contributing to data collection and the protection of local ecosystems.