Gymnosporangium juniperi-virginianae is a rust fungus known as Cedar-Apple Rust (sometimes abbreviated to CAR) that causes disease in Eastern Red Cedar and in apple trees. This fungus is unique among rusts because it produces large fruiting bodies. On cedar trees, the fruiting bodies resemble lumpy brown golf balls with long gelatinous orange tentacles bursting out of them. On apple trees, the disease causes more damage but produces only orangish spots. The complex life cycle of Cedar-Apple Rust means the fungus is easy to control, although these control methods resulted in a legal case that was argued before the Supreme Court of the United States!
fungal impacts on the economy
Wheat is the most widely grown crop in the world and is a staple food for billions of people. Diseases affecting wheat are therefore of utmost importance to food security. Some of the most destructive and difficult wheat diseases are the rusts. Wheat rust comes in three varieties: Leaf Rust, Stem Rust, and Stripe Rust, each caused by a different species of fungus. These all look slightly different but all cause rust-colored blemishes on wheat surfaces. The three species are closely related and have nearly identical life cycles. Despite this, managing the diseases is complicated and requires using resistant wheat strains, proper cultural practices, and fungicides.
Deoxynivalenol (DON) is a toxin found in grains infected with the fungus Fusarium graminearum and other Fusarium species. It is often called “vomitoxin” because it primarily causes vomiting in humans and livestock. Its long-term effects are mild, but it is still a very important mycotoxin because it is the most common mycotoxin found in food.
Fungi produce innumerable “mycotoxins” – compounds that are toxic to humans. In mushrooms, these cause symptoms ranging from gastrointestinal upset to death (see FFF#091–100 for more). Although these are of significant concern to mushroom hunters, their impact is relatively small. The most significant mycotoxins in terms of the number of people affected are produced by molds that naturally grow on food. Over the next few weeks, I will discuss some of the most problematic food-borne mycotoxins. Topping that list are the aflatoxins, which cause liver cancer and are especially problematic for people in developing nations.
Coffee Rust, also known as Coffee Leaf Rust and in Spanish as “roya,” is a disease of coffee plants that is caused by the fungus Hemileia vastatrix.1–3 H. vastatrix is, as its common name implies, a member of the rusts (FFF#130). Unlike most rusts, however, it has a simple infect-sporulate life cycle, which is likely one reason the disease has been so successful.1 Coffee Rust is a particular problem in Central America, produces 15% of the world’s arabica coffee and exports roughly 432 million kilograms of coffee to the United States annually. The region suffered a devastating outbreak of the disease in the early 2010’s and has yet to fully recover.4–6
Fungi appear in the news with surprising frequency. However, many of those stories do not provide any new information. Below is a summary of what we’ve learned about fungi from November 2016 Through February 2017. Read below to learn about: mycorrhizas, A. bisporus engineering, fungal evolution, psilocybin research, fungal concerns in medicine, rock-eating fungi, and more! Visit the associated links to get the full story.
This fungus spends its entire life inside Tall Fescue, a common livestock feed grass. While it is beneficial to the plant, it makes animals that feed on the grass sick. In the United States, the fungus costs the beef industry from $600 million to $1 billion or more every year.
Witches might not be real, but witches’ brooms certainly are – and they’re destroying chocolate! Yes, Halloween’s favorite treat (chocolate) is suffering at the hands of a disease with a Halloween-themed name: Witches’ Broom Disease. Witches’ brooms are actually fairly common and occur on many different plants. In chocolate trees (Cacao trees, Theobroma cacao, whose genus name literally means “food of the gods”), witches’ brooms are caused by the fungal pathogen Moniliophthora perniciosa and have an enormous economic impact on chocolate production in Central and South America.
Frosty Pod Rot, caused by the fungus Moniliophthora roreri, is one of the most significant pathogens of cacao trees (Theobroma cacao). The disease has been around a long time: it was first recognized in Ecuador in 1917 and first described in 1933. roreri likely evolved in Columbia, where the greatest diversity of the species is located and where cultivated cacao trees grow near closely related trees. Up until the 1950’s, Frosty Pod Rot was limited to northwestern South America. Since then, it has spread throughout Central America and into Peru and Venezuela. In these areas, Frosty Pod Rot is the most destructive cacao disease, resulting in the loss of about 30-40% of total production. The disease has not yet made it to Asia or Africa, where most of the world’s chocolate is produced, but it may just be a matter of time.
This fungus parasitizes caterpillars in the Himalayas and produces small, spike-like mushrooms. These mushrooms are highly prized for their supposed medicinal properties and have brought a lot of new wealth and new problems to the people living in the Himalayas. Ophiocordyceps sinensis fruiting bodies are known as “Yartsa Gunbu” in Tibetan and “Dōng Chóng Xià Cǎo” in Chinese, both of which translate to “winter worm, summer grass.” The English names for the fungus are much less colorful: “Caterpillar Fungus” or (more recently) “Himalayan Viagra.” sinensis (Fungi, Ascomycota, Sordariomycetes, Hypocreales, Ophiocordycipitaceae) is native to the meadows of the Himalayas and Tibetan plateau and can be found from 3,000m to 5,000m above sea level. The parasitic fungus infects a variety of species of ghost moth larvae that live underground. It initially infects the caterpillars in the late summer. By winter, the fungus is ready to kill its host. At that time, it...