randy oliver wrote:
> 
> 
> Trees use antimicrobial resins to protect new leaf buds, and any wounds in
> the bark.  Bees simply coop the plant defenses.  I haven't observed populus
> trees in the fall when bees are gathering propolis, but would GUESS that it
> would be at wounds.

In fall and winter our South Carolina Piedmont bees are very busy on the 
leaves of Baccharis halimifolia, called broom tree around here.  At 
first I thought they were collecting pollen fallen from the 
fall-blooming male plants, but on closer inspection they are usually 
harvesting the resin gland material.  This is the same genus as the 
source of the green propolis from South America which has gotten so much 
attention.  I saw a video, the plant looks identical.  Don't know if 
some of the same compounds are present.

They also love to harvest from empty equipment.  I no longer scrape the 
propolis off except when necessary for a better fit, so that it is 
available to them.  However, I have not used any chemical whatsoever in 
hives since 2001, and then only formic acid and mineral oil.

Carolyn in Plum Branch, SC 29845-0007

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