6/4/14 EDITION OF "ASK THE ARBORIST"

Today we are going to study in detail a disease that can cause aesthetic problems and partial defoliation of Apple and Hawthorn trees.  Cedar apple rust (CAR) or sometimes referred to as cedar hawthorn rust depending on which tree species you have.  (CAR) Gymnosporangium juniperi-virginianae is an unusual tree disease in that it requires two separate host trees to complete its cycle. According to literature cited from "Cornell University" (CAR) overwinters on cedar or juniper trees in the form of spherical galls.  These galls resemble parts of the Cedar tree and may not be visible to the untrained eye.  As the weather warms in spring and the rainy season begins, the once unnoticed Cedar galls will begin to swell and open with horn-like highly visible, orange-red jelly structures referred to as telia. When we have a wet spring season, spores called basidiospores (a type of micro spore structure) are released into the air.  These tiny micro spores can travel for miles depending on weather patterns and how wet our spring season is.  The basidiospores are actively looking for their summer host trees which are Apples, Crab apples and Hawthorne trees.  Once the micro spores fall onto the newly developing leaves of Apple or Hawthorne trees, its primary goal is to make residence with its summer host.  If the newly formed leaves are wet the opportunity for the micro spores to germinate into the leaf are greatly increased.  On the other hand if we have a dry spring the spores will not have the wet Apple or Hawthorne leaves available for easy germination.  Once (CAR) has germinated into the unsuspecting Apple or Hawthorne tree leaves, it produces orange-red lesions that can either become unsightly or in worst cases, defoliates the tree.  In late summer the lesions from the Apple or Hawthorne leaves, once again release their spores for migration back to the Cedar or Juniper for winter.  The interesting point about (CAR) is that it is rarely a problem for the Cedar or Juniper trees.  There are a number of preventative maintenance fungicides that can be applied to the Apple or Hawthorne tree as the leaves are opening up to provide a protective layer against (CAR).  Your Yacko and Sons Tree Service staff Forester is available to consult on Cedar apple rust or any disease, insect or tree pruning needs for your trees.  Contact Forester Jeff for your FREE TREE LOOK-UP FROM THE TRUNK-UP! and receive your free Yacko and Sons Tree Service official green and yellow Frisbee.   jeff@yackoandsons.com or 203-733-9219