Question
I have two lavender oclored Crype Myrtle trees on my parkway in Houston, TX.  They are a little over 1 year old and have been blooming wonderfully.  Within the last 2 weeks I've noticed one tree has a lot of yellow leaves, and they are sticky to the touch.  The other tree has sticky leaves as well, but no yellow leaves.  I don't see any insects on either tree, but I am concerned about the dying leaves.  I used my garden hose to try to clean off the leaves, which was somewhat helpful with removing the sticky substance.

Answer
Bob:
Sticky leaves are usually a sign of "honeydew" which is insect "poop" on which sooty mold grows, causing the leaves and stems to become black.  Looks like shellac on the leaves.  See the link below to an article on "honeydew" and sooty mold. This is caused by insects, either on this plant or one above it. Check under the leaves too.

http://www.uaex.edu/Other_Areas/publications/PDF/FSA-7555.pdf

Yellow leaves and leaf drop are often associated w/drought conditions.  A good deep drink may be called for, especially if it has been hot and dry like it has been here in Arkansas.

Regards
Steve