motor man wrote:
We have a mature tree that during about three months ( we were on
vacation) has lost the bark on parts of the tree. It looks like
something has eaten the bark away and the tree is dying above the
damage. Before cutting the parts off i would like to know what is
causuing the problem so I can prevent it elsewhere. I can send a jpg if
anyone can help on this urgent problem.
Thank you.
PS the tree is in Santa Barbara CA.


Even without a picture, I strongly guess that the tree was attacked by
brown snails (Helix aspersa). This is a serious problem in the
commercial citrus orchards here just south of you in Ventura County.
They climb lemon trees and eat the bark, leaves, and fruit. They can
kill a tree by girdling the trunk (eating the bark off completely around).

There are several ways to control brown snails. See
http://axp.ipm.ucdavis.edu/PMG/r107500111.html.

I would start with a combination of copper and poison bait. Use copper
foil as recommended in the above Web site; I have also heard of using
copper mesh. Use the bait through February. Hand pick any snails that
are up in the tree; carefully check for small, young snails that might
hide in the leaves.

In the spring, feed the tree well to promote new growth. The injuries
should heal, but it might take a year or two. Keep checking the copper
to ensure it wraps around the tree without cutting into it.

In April, when the bait has not been used for at least 6 weeks,
distribute canivorous decollate snails (Rumina decollata). You may have
to hand pick the brown snails for a year or two, but the copper should
protect your tree.

--
David E. Ross
Climate: California Mediterranean
Sunset Zone: 21 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a, very close to Sunset Zone 19)
Gardening pages at http://www.rossde.com/garden/