Colorado Peach Trees Face Devastating Canker Disease

Cytospora canker, a significant fungal disease, is severely impacting western Colorado's fruit tree orchards, particularly those famous for Palisade peaches. A recent Colorado State University survey revealed that 100% of orchards in Orchard Mesa are affected by this pathogen.

This disease results in an estimated $3 million in annual economic losses for Colorado growers. It damages large branches, potentially causing a 50% reduction in peaches per tree and drastically shortening orchard lifespans from an expected 20 years to 10 years or less. Trees infected early may not reach peak production.

Fungal spores typically enter peach trees through wounds, which can be from pruning or damage caused by severe weather. Freeze events, common in Colorado, are particularly harmful. A major freeze in 2020, following a warm October, caused temperatures to plummet dramatically, damaging trees and creating entry points for the cytospora fungus.

This correlation between cold damage and fungal infection is a key reason for the disease's prevalence in Colorado. Management strategies include removing infected trees and protecting wounds, but their efficacy is limited by growing conditions. Researchers are exploring chemical treatments and cultivar tolerance.

The cytospora working group, a collaboration of growers, researchers, and extension personnel, is dedicated to developing solutions. They are investigating factors influencing disease development and establishing best practices to ensure the continued vibrancy of Colorado's peach industry.