The Lee County Bradford Pear Bounty is coming up on Saturday, October 28, 2023. As we approach the event, we are going to take some time to highlight how invasive species impact our modern landscapes. Remove any callery pears on your property by then and you can get free replacement trees, up to five trees.

Learn more about the program

Fungi are everywhere. I mean everywhere. They grow in the soil, associate with plant roots, fly through the air, and help us digest our food (and the food of all animals). There are hundreds of thousands of species of fungi around the world, most of which scientists haven’t even begun to describe. They have complex life cycles, and need one or more hosts to procreate (see my article on cedar apple rust!). Most are microscopic at best and only a few species make mushrooms you’d ever notice. They are the glue and the grease of many supporting ecosystem services and we, as humans, benefit from them being intricately involved in biological functions.

Yet, they can also be ecologically devastating. Ecosystems are finely-tuned machines when you get down to it. They are constantly tinkering with themselves, but they generally hum along. Humans move around at lightspeed compared to ecosystems and we have caused havoc moving fungi as we’ve traveled, and imported and exported goods around the world. We have a better understanding of these mechanisms and our impact on our environments, but we still have room for improvement. Here are a few cautionary tales.

American Chestnuts, Once Mighty Giants

My grandfather told stories of how his family would fill wagons full of American chestnuts, Castenea dentata, around Christmas time in the North Carolina mountains in the 1940s and 1950s, but those days are long past. Chestnut Blight, caused by the fungus Cryphonectria parasitica, was introduced to American forests when we started importing Asian Chestnut species, Castenea mollissima and C. crenata, in the late 1800s. After being first detected in forests in NY in 1920, the pathogen systematically killed off or weakened full-grown, giant Chestnut trees across their entire native range. Now only stumps remain, some trying to send up spindly sprouts that eventually get infected with the fungus and dieback again.

Thousand Cankers Disease- Are Black Walnuts the next mighty tree to follow the way of the American Chestnut?

With a name like Thousand Cankers Disease, you can picture in your mind what a tree might look like with this fatal fungus. Black walnuts, Juglans nigra, in Western U.S. states have been dying off from infestations that may start with hundreds of holes less than 0.5 mm and will eventually be surrounded by a black oozing wound. Thousand Cankers Disease is a fairly new disease, and is caused by the fungus Geosmithia morbida. The fungal spores are transported by walnut bark beetle, Pityophthorus juglandis, but they have been detected to be spread by other species of beetles, as well. The fungus infects the stem, and when there is a heavy infestation it can interrupt the tree’s ability to transport sugars and water, and it eventually dies.

If the Spring Peepers don’t herald Spring, who will?

Fungi don’t only infect trees! The amphibian chytrid fungi, Batrachochytrium dendrobatidis and B. salamandrivorans, cause Chytridiomycosis, and it has been devastating amphibians around the world. Frogs, toads, lizards and salamanders, just to name a few, have been dying off in droves and affecting ecosystem functions. The fungus infects the skin of the animals and makes it hard for them to regulate water and salt movement in their skins. These animals are important predators of insects and other aquatic animals, as well as critical prey for larger animals, like birds and large fish. The fungus is easily spread through infected water

.White-Nose Syndrome Knocks Out Our Natural Mosquito Control

Bats are some of the most voracious consumers of mosquitos and other agricultural pests. One of the more tragic and terrifying stories is the one of White-Nose Syndrome, which is killing bat species in the United States and Canada at a devastating rate. The fungus, Pseudogymnoascus destructans, is a psychrophilic (cold-loving) fungus that was first discovered in caves in New York in 2006. Scientists suspect spelunkers introduced the fungus into the cave after they had traveled from Europe to Upstate New York without disinfecting their gear. The fungus then mutated into a new species that then became a pathogen on bats hibernating in the caves. The fungus infects the tissues of their noses and skin, and does not allow for them to effectively hibernate. Infected bats suffer from dehydration, starvation, and frequently death. It is now present in 38 states and eight Canadian provinces. The populations of three species of bats (of the 12 that are affected) have declined by over 90 percent in less than 10 years. White-nose syndrome could lead to their extinction in a very short time.

Quarantine, Sanitation, Scouting and Eradication Work!

In the face of tiny organisms we can’t see, what can we do? Quarantine, sanitation, scouting and eradication work! You can do this in your own backyard and on your own property. Be mindful of what plants and animals you bring on to your property and be aware of issues in the community around you. Clean and/or sterilize tools and equipment when you move it between properties, and demand that people you hire do the same. A quickly spritz your tools with isopropyl alcohol to kill pathogens between pruning plants. Use an air compressor to blow off plant debris to stop the spread of weed seeds and pathogens to your property. Clean the soles of your shoes before and after you go hiking, especially across long distances. There are little things you can do to make a difference!

Resources

Towards management of invasive ectomycorrhizal fungi– Dickle, et al. (2016)

NC State University Profile on Chestnut Blight

Forest Pathology Write up on Chestnut Blight

Thousand Canker Disease moving east

Guide to Thousand Cankers Disease and Walnut Twig Beetle

GEOSMITHIA SPECIES IN FLORIDA: COMMON FUNGAL SYMBIONTS OF WOOD-BORING BARK BEETLES– Yin-Tse Huang and Jiri Hulcr

Diagnosing Thousand Cankers Disease of Walnut– Whitney Cranshaw and Ned Tisserat Colorado State University

Chytridiomycosis- Cornell Wildlife Health Lab

Pseudogymnoascus destructans growth in wood, soil and guano substrates– Urbina, et al.

Ecology and impacts of white-nose syndrome on bats– Hoyt, Kilpatrick and Langwig

White-Nose Syndrome- Cornell Wildlife Health Lab

Bats

Going out for dinner—The consumption of agriculture pests by bats in urban areas– Aguiar, et al.