Swiss needle cast of Douglas fir Phaeocryptopus gaeumannii
Symptoms / species
Impact / measures
Needles grey and later brown,(only) on the lower surface small black dots in rows, remaining attached to the twigs for a long time, mostly shed only after 2-3 years.
Affected tree species
Common weak parasite of Douglas fir, often a consequence of or associated with frost damage, sometimes only following stand density (light deficiency, high air humidity); no serious danger for the tree. Further information (in German) Gehölzkrankheiten in Wort und Bild (TUM Weihenstephan).
Curative measures No curative measures recommended. Preventive measures: hygienic: thinning of plants, use of chemical compounds (see federal register of plant protection) only in cultures or young stands, which are heavily infested: fungicide treatment as a prevention for the next season (repeated application).
Fruiting bodies on the lower surface of the needle, emerging through stomata
numerous fruiting bodies on the lower surface of the needles