Warning: New York Apple Trees at Risk From 'Exploding Hearts'

Recent weather in the Hudson Valley has been the perfect recipe for one of the most frustrating fungi in the state... and it could be threatening New York apple trees.

It's already been a tough 12 months for apple growers in the Empire State. From the "apple-apocalypse" of 2023 to recent frosts that led some orchards to rely on wind machines and hovering helicopters to save budding blossoms, it seems like work never ends to protect one of the state's most famous crops. Now, a new threat has emerged.

A fungus called Cedar Apple Rust may be currently threatening New York state apple trees (TSM Poughkeepsie)

Cedar Apple Rust in New York State

Cedar Apple Rust (Gymnosporangium juniperi-virginianae) has made itself at home in the northeast United States. The fungus thrives when two specific trees are in close proximity to one another, specifically a species of juniper tree such as red cedar, and an apple tree. Together, they can wreak havoc on both hosts.

Cedar Apple Rust often begins as galls on red cedar trees in New York (TSM Poughkeepsie)

What Is Cedar Apple Rust?

The fungus begins as a gall on the juniper tree, like the red cedar above. After absorbing enough water from spring rains, the often heart-shaped galls begin to erupt small spikes called telial horns, which continue to grow until they "explode" into gelatinous tendrils (below). This is also a sign that spores have been released in the air and are on the search for a nearby apple tree.

Cedar Apple Rust galls emit gelatinous "telial horns" (TSM Poughkeepsie)

How Cedar Apple Rust Affects New York Apple Trees

While galls form on the cedar trees, the "rust" part of Cedar Apple Rust's name begins when spores find apple tree leaves. By the month of June, affected trees can start to show "rust spots" on their leaves (below). In certain cases, the fungus can lower apple production and even kill the tree in serious instances.

Leaves suffering from Cedar Apple Rust can literally give the appearance of "rusting" (David Taylor via USDA)

Fighting Cedar Apple Rust in New York State

In some cases, juniper trees within a three mile radius of apple orchards are removed to avoid the possibility of a fungus infection. While the fungus can be harmful, many trees (both apple and cedar) often tolerate Cedar Apple Rust. Galls can also be pruned before telial horn begin to grow.

5 of New York's Most Devastating Invasive Species

Here are 5 species that have invaded New York State and in some cases they must be killed. We are talking about fish that walk on land, plants that cause severe burns and insects that could wipe out a variety of crops that we rely on.

Keep an eye out for these species and you hike, work around the yard or do some fishing this year. Should you locate any of these it is important to report where and when you found them to the New York State DEC.

Gallery Credit: Karolyi

New York State's Invasive Plants To Be On The Lookout For

These seven invasive plants have become a nuisance to the wildlife and people living in New York State. Learn more about them and how to remove them at the New York State Department of Environmental Conservation here.