Question
My Yoshino cherry tree looks as if it is dying.  It has been a long dry summer, but others in my yard look fine.  I noticed today that there is what looks to be a gel on the bark in various spots.  I touched one and they are hard, like a resin.  What is it and what can I do about it?

Answer
Hi Deb:
This gel is a product of the tree. It is produced as a defense mechanism to injury. Most often, this "injury" is a very small insect that is boring into the wood. Enough tunneling can cause the tree to decline over time. I am not sure of the types of insecticides that are currently available. The effectiveness of these materials is questionable since the insect is already inside the tree. This makes control difficult. Most insecticides are more effective as preventatives- applied as trunk spray to prevent the "critter" from entering.
Check in w/ your local garden center or nursery for some options as far as insecticides go.

Regards
Steve