Ivy Anthracnose

Often called the architect of "Ivy Anthracnose," Colletotrichum trichellum is less of a forest toadstool and more of a microscopic landscaper—though not a very helpful one! Rather than a traditional cap and stem, this fungus manifests as a series of dark, "freckled" lesions on the leaves of English Ivy. It is a master of the damp, shaded corners of the garden, where it quietly reshapes the appearance of its host.

🔍 How to Identify

• 🍂 Concentric Spots: Look for circular, tan-to-brown lesions on ivy leaves, often bordered by a distinct, dark purple or black ring.
• 🪡 Tiny Bristles: If you look closely (or use a magnifying glass), the black dots in the center of the spots feature tiny, dark, needle-like hairs called setae.
• 🕳️ Shot-Hole Effect: In advanced stages, the center of the infected leaf tissue may dry out and crumble away, leaving ragged holes in the foliage.

🌲 Habitat & Ecology

• 🌿 The Ivy Specialist: This fungus is a specialist that primarily targets Hedera species (English Ivy). It survives the winter on fallen leaf debris, waiting for the return of wet weather.
• 💧 Splash Distribution: Unlike mushrooms that use wind to spread spores, this species relies on "splash dispersal." Raindrops or garden hoses hit the infected spots and catapult the spores onto neighboring healthy leaves.

⚠️ Safety & Toxicity

• 🚫 WARNING: While Colletotrichum trichellum is not a "poisonous mushroom" in the sense of a toadstool, it is a persistent plant pathogen. It is not known to be toxic to humans or pets through casual contact.
• 🧤 Garden Hygiene: The primary "danger" is to your landscape. To prevent spreading the infection, avoid handling healthy plants after touching infected ivy, and always use clean shears. Do not put infected leaves in your home compost pile, as the spores can survive the process.

✨ Fun Fact

The term "Anthracnose" used to describe this fungus comes from the Greek word for "coal" (anthrax). This refers to the dark, scorched, or carbon-like appearance the fungus leaves on the plant's foliage as the tissue dies.