CARLOS LOVERA m wrote
in pdirect.com:

I have a guava tree on which I been noticing dead branches. I finally
went to investigate and noticed a huge hole when a branch must have
broken off. The were a lot of dead tissue in the hole and carpenter
ants. I cleaned out the area with drill, sprayed the ants as they fled
and proceded to filling the area with Durhams putty after spraying all
the surfaces with tar paint. This morning as I am applying Tanglefoot I
noticed that the ants are also at the base. They seem to have eaten
away a good portion of the tree from below. I cleaned and sprayed the
area. My issue. I want to reach from beneath and apply a good measure
of roofing cement to the affected area and thus keep ants from entering
their old home. Will roofing cement do the trick. It cant hurt at this
point. That and keep area around d the tree clean.
Thnk you

I don't know anything about guava trees. However, it is my understanding
(and experience) that carpenter ants like to chew up _decaying_ wood and
that suggests your tree is in trouble, and no plugging up of holes is likely
to be a long term solution.