Colorado peach growers are suffering millions of dollars in losses due to cytospora canker, a fungal disease that has infected every orchard surveyed in the state. A recent study estimated the disease causes at least $3 million in annual economic losses for Colorado growers, with 100% of orchards on Orchard Mesa found to have infected trees.
The disease dramatically shortens the productive life of peach trees. While growers expect trees to live for 20 years, cytospora canker has halved orchard lifespan in Colorado to 10 years or fewer. Trees infected in their first or second year typically die by year four or five, before reaching peak production. In severely infected large branches, known as scaffolds, damage can result in a 50% loss of peaches per tree.
Cytospora canker enters through wounds caused by pruning, freezing, or hail. Freeze events are particularly damaging in Colorado, such as a major event in 2020 when temperatures dropped from 65F to below 10F within 48 hours near Hotchkiss, killing tens of thousands of peach trees and leaving survivors vulnerable to infection.
The disease, caused by fungi in the genus Cytospora, has been present in US fruit trees since at least 1892. Management strategies are limited, with growers advised to remove infected trees, protect wounds with chemicals, and reduce stress.
Colorado produced roughly 15,000 tons of peaches in 2024, valued at $34 million. However, fruit tree production in the Intermountain West faces additional threats from diminishing water supplies, spring frosts, and variable winter temperatures, which further exacerbate the impact of the disease.
