I am an arborist in Porland, OR. and I'm wondering what could cause necrosis between the veins in a vine maple. The twigs are somewhat sticky, like honeydew but there is no stickiness on the glass table below. One whole leader is dead and has what looks like sunscald. The leaves on the remainder of the tree are drying out. There is also a white powdery stuff that resembles scale but is in smaller patches. Any hints? It has also been very dry. Could it be more than one thing?

Reply to post by James Wentworth-Plato, on August 15, 2000 at 22:25:50:

Without seeing the tree, my first thought was root problems. One leader is dead, others failing. This is a wide-spread systemic problem, not localized as insect infestation would be. The interveinal necrosis may be simply the result of the lack of moisture to the leaves, due to poor root capability. Girdling roots, root loss from infection or construction are the first places to look. Also check for the possibility of vascular infection (Verticillium, etc.), if it is known to be common in your area.

Arborist News magazine (August 2000) has a good article dealing with diagnosis protocols.