Pucciniastrum areolatum

Twin-spotted quaker

Description

On Norway spruce, female flowers that are infected in the spring form cones with whitish pycnia (spermogonia) on the inner side of the cone scales. During the summer the cones develop numerous spherical brown aecia. At high relative humidity, the scales of affected cones appear ruffled, while the healthy cones remain closed. The affected cones produces only a few seeds if any at all. The rust produces spores of stages 0 and I on Norway spruce, II and III on leaves of various bird cherry species (uredinia on upper and telia on the lower side). Basidiospores (stage IV) infect female flowers of the first host (Norway spruce). The rust is also a cause of young shoot malformation in Norway spruce, resembling shoots of Scots pine infected with Melampsora pinitorqua.

Symptom

The affected cones produces only a few seeds if any at all. The rust is also a cause of young shoot malformation in Norway spruce, resembling shoots of Scots pine infected with Melampsora pinitorqua.

Tree Species: Spruce

Part of a plant- attacked: Leaf / Needle, Fruit / Seed

Pest significance: Harmful

Pest Category: Fungi

Invasive Species: No

Present in EU: Yes