Fire Blight and Fruit Trees

Withering Leaves, Candy-Cane Crooks – Is it Fire Blight?

Kari A. Peter, Ph.D. Assistant Professor, Tree Fruit Pathology Kari A. Peter, Ph.D. Penn State Fruit Research and Extension Center

Kari A. Peter, Ph.D.

Have you noticed withering leaves, weeping sores, or candy-cane like crooks at the tips of your fruit tree’s branches? You might have a fire blight  infection on your hands. Recently, the Urban Forestry Radio Show sat down with Dr Kari A. Peter, Assistant Professor of Fruit Tree Pathology at Penn State Fruit Research and Extension Center to discuss fire blight, which can damage or kill your fruit trees, and even entire orchards.

How Fire Blight Spreads

Blossom Blight. Photo credit: Dr Kari Peter

Blossom Blight. Photo credit: Dr Kari Peter

When a tree is in bloom, the fire blight bacteria enters the blossoms with the help of pollinators, which spread the infection from tree to tree. The fire blight bacteria will then eventually progress throughout the tree, infecting the tree’s youngest shoots. Untreated, the blight will overwinter, and persist from year to year. If it’s a young or small enough tree, the infection can reach the trunk and kill the tree outright.

Fire blight is a bacterial disease believed to be native to North America. It affects a number of species, including apple and pear trees. Early signs of fire blight include blackening around the leaves, gradually causing withering and wood death throughout the branch.

Learn More About Fire Blight

If you have concerns or curiosity about fire blight, tune into Episode 12 of the Urban Forestry Radio Show to listen in on an in-depth question and answer session with Dr Peter. This episode features listener questions and a more in-depth discussion of what fire blight is, as well as possible ways to manage the disease.



Kameron Chausse

Kameron Chausse

Intern at

Kameron Chausse is a Windsor, Ontario based writer and student at St Clair College. He is currently an intern for the fruit tree care education website