Calycanthus floridus Krank?

[deluxe89]

Guten Abend zusammen,

ich habe letzen Herbst einen Calycanthus floridus gepflanzt,
nun hat er schon über die gesamte diesjährige Vegetationsperiode schwarze Flecken auf den Blätter.

Vielleicht weiß ja jemand nähres über diese Flecken und was man dagegen unternehmen kann.

Ich vermute das es eine Pilzkrankheit ist..bin mir aber nicht sicher

Vielen Dank schon mal im Voraus!

[bee]

Hallo,
dazu findet man leider wenige Informationen.
Auf deutschen Webseiten heißt es (ungefähr) "PIlzkrankheiten unbekannt".

Hier (engl.) steht allerdings doch, dass für schwarze und braune Flecken auf den Blättern Pilze oder Bakterien verantwortlich sein können. (Und man ist so schlau wie zuvor...)
http://www.backyardgardener.com/plantname/pda_a209.html

unter "Problems":

Problems
Fungi : Powdery Mildew
Powdery Mildew is usually found on plants that do not have enough air circulation or adequate light. Problems are worse where nights are cool and days are warm and humid. The powdery white or gray fungus is usually found on the upper surface of leaves or fruit. Leaves will often turn yellow or brown, curl up, and drop off. New foliage emerges crinkled and distorted. Fruit will be dwarfed and often drops early.
Prevention and Control: Plant resistant varieties and space plants properly so they receive adequate light and air circulation. Always water from below, keeping water off the foliage. This is paramount for roses. Go easy on the nitrogen fertilizer. Apply fungicides according to label directions before problem becomes severe and follow directions exactly, not missing any required treatments. Sanitation is a must - clean up and remove all leaves, flowers, or debris in the fall and destroy.

Fungi : Leaf Spots
Leaf spots are caused by fungi or bacteria. Brown or black spots and patches may be either ragged or circular, with a water soaked or yellow-edged appearance. Insects, rain, dirty garden tools, or even people can help its spread.
Prevention and Control: Remove infected leaves when the plant is dry. Leaves that collect around the base of the plant should be raked up and disposed of. Avoid overhead irrigation if possible; water should be directed at soil level. For fungal leaf spots, use a recommended fungicide according to label directions.