Fungus Fact Friday

Tagged: economy

fungal impacts on the economy

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Fungus Fact

#019: Apiosporina morbosa, Black Knot

And now for something completely different: how to recognize different types of trees from quite a long way away.*  Black Cherry (Prunus serotina) is the easiest tree in eastern North America to identify, thanks to the fungus Apiosporina morbosa, commonly known as Black Knot.  Most Black Cherry trees are infected with A. morbosa, which causes dark swellings on branches and trunks.  Older tree trunks are often marred by large swellings caused by A. morbosa that are up to twice the size of the trunk.  These “knots” are easy to spot from a distance (especially in winter), so take advantage of this and amaze your friends by pointing out Black Cherry trees without relying on bark, leaves, or other details!  On twigs and smaller branches, Black Knot makes the branches lumpy and thickened in places, looking remarkably like “dried cat poop on a stick” (thank Michael Kuo for that apt analogy).

cryphonectria parasitica on wood 1

Fungus Fact

#222: Cryphonectria parasitica, Chestnut Blight

The American Chestnut Tree, Castanea dentata, was once one of the dominant trees in eastern North American forests. It rivalled oak trees in terms of size and abundance. The trees were also highly valued for their rot-resistant wood and edible seeds, making it one of the most economically important trees in eastern North America. So, if the trees were so common and so important, where are they today? The downfall of the American Chestnut began in New York in 1904, when a disease called Chestnut Blight suddenly appeared and swept across the continent. By 1950, the disease had infected and killed almost every American Chestnut. Chestnut Blight is caused by the Asian fungus Cryphonectria parasitica, which grows in the outer wood of the tree and essentially chokes trees to death. The aggressive pathogen has doomed the American Chestnut to extinction, unless humans can come up with a solution.

Cedar-Apple Rust telial horns 8

Fungus Fact

#087: Gymnosporangium juniperi-virginianae, Cedar-Apple Rust

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!

Wheat Leaf Rust, Wheat Stripe Rust, and Wheat Stem Rust 1

Fungus Fact

#208: Rust Diseases of Wheat

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.

Fusarium head blight 1

Fungus Fact

#203: Deoxynivalenol

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.

Aspergillus flavus 3

Fungus Fact

#202: Aflatoxins

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 0

Fungus Fact

#049: Coffee Rust

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 in the News Image 0

News Update

Mycology News: April to June 2016

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.

#115: Neotyphodium coenophialum, Tall Fescue Endophyte 1

Fungus Fact

#115: Neotyphodium coenophialum, Tall Fescue Endophyte

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.

#113: Moniliophthora perniciosa, Witches’ Broom Disease of Cacao Trees 1

Fungus Fact

#113: Moniliophthora perniciosa, Witches’ Broom Disease of Cacao Trees

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.