Photo by Guido Blokker on Unsplash.

OK, so they’re not plants but every good gardener knows that mycorrhizae, the thread-like fungi that lace our soil, are of our best friends for soil health and plant growth. With that in mind, here are a few recent stories about fungi and mushrooms.

Renato Tomassetti and Bella after she found a truffle. “Black gold,” Mr. Tomassetti said. Photo credit: Stephanie Gengotti for The New York Times

The Perils of Hunting for Truffles

Jason Horowitz, the New York Times’ Rome bureau chief writes about the highly competitive business of truffle-hunting in Italy. Competition is so cut-throat that some have taken to poisoning the dogs of known truffle hunters. Horowitz’s article focuses on 80-year-old Renato Tomassetti and his dog Bella, an energetic Lagotto Romagnolo, a stocky, curly-haired breed also known as  Italy’s “Truffle Dog”. The article is lushly illustrated with photos by Stepanie Gengotti.

Mushrooms can live without us, but we can’t live without them. (Photo: Zahra via Unsplash.

No fungi? No forests, no food, no future!

David Suzuki with contributions from senior editor and writer Ian Hanington writes about the importance of fungi to humans. Cheese, bread, wine, beer, kombucha and chocolate would not exist without fungi. It makes all these tasty items possible. In fact, almost all food production relies on fungi. Most plants need it to obtain nutrients and water. Trees and other plants in a forest connect through intricate fungal, or mycorrhizal, networks of tiny mycelium threads that transfer nutrients, water and information between them, and that facilitate decomposition, without which life couldn’t go on. All fermented foods — including beer, wine, chocolate, cheese, bread, soy sauce and tofu — require yeasts, a single-celled fungus. Fungi have also been indispensable in preserving foods. And cows and other ruminants need gut fungi to break down grass. This Guardian article reports that fungi are also responsible for many important medical breakthroughs and for a lot of carbon sequestration.

For such an important group of organisms, we know almost nothing about fungi. Until the 1970s, fungi were classified as plants. We now know they are closer to animals. “They’re really weird organisms with the most bizarre life cycle. And yet when you understand their role in the Earth’s ecosystem, you realise that they underpin life on Earth,” said Kathy Willis, director of science at the Royal Botanic Gardens, Kew, which leads “State of the World’s Plants and Fungi” assessments.

Photo by Irina Iriser on Pexels.

Growing Mushrooms without Pesticides

Ali Jones reports in Horizon, the EU research and innovation magazine, on how La Rioja in northern Spain is both a centre for mushroom growing and research into greener growing strategies. Growing mushrooms commercially requires managing humidity, temperature and light to produce a regular, quality crop while contending with pest control. For now, pest control means relying on pesticides, which are becoming expensive and, of course, have environmental risks. Pablo Martínez, an agronomist, was drawn to the specialist mushroom sector after a chance conversation with a former colleague. Based at the Mushroom Technological Research Centre of La Rioja (CTICH), Martínez manages a Europe-wide project to tackle the environmental challenges faced by the industry.

Mushrooms are grown on a substrate, or base layer, made of straw and animal manure, then covered with a thick blanket of peat known as the casing. Made up of partially decayed vegetation, peat perfectly mimics nature’s forest floors that so readily yield mushrooms. The depletion of precious finite peatlands is a global concern. These wetlands store more carbon than all other vegetation types in the world combined and their conservation is ever more important for countering climate change. “Mounting restrictions on peat extraction in European countries threaten the long-term continuity of peat supplies,” said Martínez. “We’re looking to develop a new product for growing mushrooms that could cut pesticide use by 90% while reducing the industry’s reliance on peat.” EU-funded research aims to to create a low-peat sustainable casing for cultivated mushrooms made from renewable materials sourced close to existing mushroom production. While the exact details are under wraps, it will combine with a substance known as a biostimulant to enhance the natural growing processes and strengthen the mushroom mycelium in their early phase, protecting them against disease without the need for chemical pesticides.

Meanwhile, in Norway, two mushroom enthusiasts have pioneered a project to explore whether the crop could be cultivated in food waste. The EU-funded initiative is called VegWaMus CirCrop.

The death cap mushroom (Amanita phalloides), a small, green-tinged mushroom, sprouting from a forest floor. (Image credit: Pierre/Alamy Stock Photo)

How the world’s deadliest mushroom conquered California

Writing in Live Science, Ben Turner reports on the spread of the aptly-named death cap mushroom. The poisonous “death cap” mushroom (Amanita phalloides) is an invasive fungus whose fatal amatoxin accounts for more than 90% of deaths from mushrooms worldwide, but how it spread from its European origins to colonize every continent except Antarctica has long been a mystery. Now, a study published to the preprint server biorXiv, has found a reason why: the California version of the death cap can fertilize itself and produce perfect copies, sidestepping the need to mate before wafting its spores over an unconquered region.

“The diverse reproductive strategies of invasive death caps are likely facilitating its rapid spread, revealing a profound similarity between plant, animal and fungal invasions,” the researchers wrote in the preprint.

Photo credit: Tim Sandall

Adding fungi makes rosemary tastier

Finally, research from the Royal Horticultural Society (RHS), Vitacress Herbs and Royal Holloway has shown that the addition of mycorrhizal fungi to soil leads to increased production of essential oils in rosemary, making the plants more aromatic and flavorsome. Adding mycorrhizal fungi did not affect the shape or structure of the plant, just the production of the compounds that enhance the flavor and taste of rosemary. This means that home gardeners and trade growers will be able to produce rosemary plants with a consistent appearance but with the potential for extra flavor. The research was published in Life.

Pests & Diseases Pollinators, Molluscs and Other Invertebrates

Natural Pest Control

Replacing pesticides with ants to protect crops: A team of researchers affiliated with several institutions in Brazil, working with one colleague from Spain and another from the U.S., has found evidence that suggests ants can be used as a natural pesticide for a wide variety of crops.

In their paper published in Proceedings of the Royal Society B: Biological Sciences, the group describes how they analyzed studies conducted by researchers across the world to learn more about the possible use of natural pest control options by farmers and what they learned by doing so. Because of concerns about pesticide use, researchers around the world have started looking into the possibility of using natural pesticides.

One such natural approach has involved the use of ants—they leave the crops alone and instead feed on the insects that damage plants. Use of ants to control pests has a long history, citrus growers in China, for example, have been using ants to control pests in fruit trees for centuries. In this new effort, the researchers wondered what other researchers have found when looking into the use of ants as a natural pesticide.

Fifty-two published research papers involved looking into the use of ants as a way to control pests, covering 17 different types of crops. In analyzing the papers, the researchers found that most of the studies had led to discoveries of ants providing a high level of pest control—and in some cases, the ants were even better at it than commercial pesticides. They also found that the ants did their best work when used with crops grown in partial shade, and were the least effective when used with crops that produce honeydew—in such plants, ants tended to farm the insects, such as aphids, in order to provide themselves with the sweet liquid.

The researchers conclude by suggesting that the use of ants to control pests appears to be a sustainable and inexpensive way to control pests on both large and small farms.