Glomerella Leaf Spot – a new disease affecting Golden Delicious apples in NY?

From Dave Rosenberger, Cornell University, Dept. of Plant Pathology, Hudson Valley Lab:

Golden Delicious trees in Hudson Valley Lab research orchard are yellowing and defoliating. Upon closer inspection, and based on an alert from Dr. Keith Yoder in Virginia, it may not be the physiological leaf blotch (necrotic leaf blotch or Golden Delicious leaf blotch), but a fungal disease, Glomerella leaf spot. Jeff Alicandro of AgriAssistance had also raised questions earlier this week about whether defoliation of Golden Delicious that he is seeing in Wayne County, NY, might be caused by Glomerella.

Look for dead spots on leaves with a concentric ring pattern. If you are seeing the symptoms described by Keith Yoder on his blog at http://treefruitdisease.blogspot.com,

then you may want to consider an application of Pristine to slow it down, especially on late-maturing apple cultivars. Golden Delicious, Gala, Pink Lady, Goldrush, and Pristine cultivars are known to be susceptible. This disease can result in fruit rots, as well!