Boletinellus merulioides is an odd mushroom, both in appearance and ecology. The Ash Tree Bolete can be readily identified by its tube surface – which is only a few millimeters thick and looks more like a network of ridges – and by the fact that it fruits under only ash trees. B. merulioides appears under ash because it has a unique symbiotic relationship with a pest of ash trees: the Leafcurl Ash Aphid.
fungal interactions with trees
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
Sirex noctilio, known as the “Sirex woodwasp” or “European woodwasp” (sometimes spelled “wood wasp”), is an invasive species that attacks most species of pine trees. Interestingly, the insect is dependent upon the fungus Amylostereum aerolatum to complete its life cycle. The Sirex woodwasp carries the fungus with it to new trees and in return the fungus becomes a meal for the Sirex woodwasp’s larvae.
This emerging fungal disease of ash trees was first reported in 1992 in Poland. Over the past 24 years, Hymenoscyphus fraxineus has spread throughout Europe and (with the help of the invasive Emerald Ash Borer beetle) is now poised to eradicate ash trees from the entire continent.
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.
The banana that you know and love may soon be a thing of the past. I know, you probably think that I’m exaggerating the threat to this ubiquitous crop, but the possibility of bananas disappearing from grocery shelves forever is very real. In fact, it nearly happened once before. Here is a brief history of the modern banana: in the 1950’s, bananas were wiped out by a disease called Panama Disease. To save the crop, a resistant variety was discovered. Today, Panama Disease has evolved to attack the resistant variety, thus threatening to decimate banana production for a second time. This time, however, there is not a fallback option.
Unlike most fungal rusts, Cedar-Apple Rust produces large fruiting bodies during one stage in its life cycle. These structures are probably the strangest-looking fruiting bodies found in North America.
This fungus is one of a number of ascomycetes that form hard, flat fruiting surfaces on dead or dying hardwood trees. Most fungi with this fruiting habit are black, making the tree appear as though it were burned in discrete spots. However, at a certain stage in its fruiting body development, Biscogniauxia atropunctata is light gray or white and covered in small, black dots.
This woody shelf fungus is found on locust trees. Because of this, identification of this fungus is greatly simplified if you know your trees.
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.