Wednesday, May 21, 2014
Gooey Orange Fungi on Junipers
M. Grabowski, UMN Extension Educator
This time of year, several species of fungi from the genera Gymnosporangium are producing bright orange gelatinous spore producing structures on the branches of Junipers. The brilliant orange color of these fungi gives them their common name: Rust. Cedar apple rust is perhaps the most well known of the Gymnosporangium rust fungi, but here in Minnesota four different species can be found infecting junipers. Hawthorn rust, quince rust and juniper broom rust all produce similar gelatinous bright orange spore producing structures on junipers. Although these fungi can be startling to see, they rarely cause significant damage to the junipers. Spores produced in these orange gelatinous structures will not reinfect the juniper. Instead spores are carried by wind and rain to infect nearby trees and shrubs in the Rosaceae family. Each of the four Gymnosporangium rust fungi infect different members of the Rosaceae family including crabapple, serviceberry, and hawthorn. To learn more read Cedar Apple Rust and other Gymnosporangium Rusts by UMN Extension.