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Gymnosporangium cornutum

Mountain ash juniper rust

Description

It is a dioecious rust. Primary host trees are junipers (Juniperus) on which are formed telia - 2-4 cm long lumps or rolls, so-called telial rolls. From them are released spores (teliospores) which infect the second host tree - mountain ash leaves. On mountain ash are formed concave yellow spots with outgrowths on the bottom side, aecial rolls from which the spores infect junipers. The fungus does not cause any serious damage to juniper, however, it aesthetically damages mountain ash.

Symptom

On mountain ash are formed concave yellow spots with outgrowths on the bottom side, aecial rolls from which the spores infect junipers.

Tree Species: Rowan, Whitebeam

Part of a plant- attacked: Leaf / Needle

Pest significance: Less harmful

Pest Category: Fungi

Invasive Species: No

Present in EU: Yes

Last observations

There are a total of 2 observations of the species in the system

Gymnosporangium cornutumMountain ash juniper rust
andrej
Number of votes: 0
Published: 10.8.2025

Gymnosporangium cornutumMountain ash juniper rust
andrej
Number of votes: 0
Published: 10.8.2025