Oregon White Oak

David Biek dbiek at delphi.com
Mon Jun 5 01:45:20 EST 1995

Around Tacoma, Washinton, I've noticed that the leaves of Quercus garryana
are dotted with a clear, sweet exudate. From a near distance, the leaves have
a varnished look; under a lens the there is no sign of aphids or any other
insect which might be responsible. The amount of liquid varies, but not in
any patterned way that I've been able to determine; one one leaf, a droplet
had formed at the leaf's tip.
Can anyone explain for me what's causing this? I haven't noticed in years
past anything like this.

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