Hi, I have an 80+ year old oak tree in my yard. Last year had Arborguard
come out and they told me it had a beetle infestation and that the cost to
treat it would be in the thousands. Needless to say, did not treat.
Haven't noticed anything all winter, but now I notice ants crawling around
the base of the tree and into the bark (maybe the beetles are coming!)
Does anyone know of a good way (preferable non-toxic to my cats) way to
help my tree out, maybe support it with more nutrition and also keeps the
bugs out? Do you think it will kill the tree? Thanks--
My valley white oak (Quercus lobata) always has ants, but it is
If you do have a problem with borers, there is a systemic
insecticide for trees that comes in little plastic "bullets". You
have to buy enough to space them about four inches apart around the
trunk about 3-6 feet above the ground. You use a drill to make
holes (the package describes the size) in a spiral that winds twice
around the turnk and insert the "bullets".
I used this on an ash tree that was severely infested with ash
white fly, which almost defoliated the tree and made a sticky mess
in my yard and even inside the house. I had to do this two years
in a row, until a newly introduced parasitic wasp brought the white
fly under control.
I don't remember the name of the product, but I found it at a local
nursery. Follow the instructions carefully. It should be safe for
your cats, which should avoid eating oak leafs (which can be
I would avoid over feeding an oak. Many oaks prefer a "lean"
soil. One light application of regular lawn food (without
insecticide or herbicide in it) might be okay. Scatter this across
the entire area under the tree's branches. Oak roots often spread
as wide as the canopy.
Be careful with water. If your oak is a variety that likes
moisture in the summer, be mindful of drought conditions and keep
it watered. If your oak is like mine -- native to a climate that
usually has no rain in the summer at all -- do not irrigate.
David E. Ross
Climate: California Mediterranean
The best thing you can do to promote general tree health is to mulch.
Use wood chips, pine bark, or any organic material that suits you
aesthetically. Apply it in a layer 3 inches deep all around the
trunk. Do not heap mulch against the base of the tree; you should be
able to see the root flares where they enter the soil. Cover as wide
an area as you are willing. I'd say minimum 6 feet from trunk, but
for a tree as large as yours you might even go farther.
Mulch reduces competition from grass and weeds, thus eliminating
injury from string trimmers. It blankets the soil so temperature
spikes are less severe. It retains moisture. As it decays, it
releases nutrients into the soil and loosens compaction, thereby
reviving the soil ecosystem and making roots happy. Happy roots make
happy trees. Happy trees are better able to resist attack from
disease or pests.
For more info about the International Society of Arboriculture, please visit
For consumer info about tree care, visit http://www.treesaregood.com /
I don't believe their diagnosis since the price of the treatment tells me
they are less than ethical. Have the tree re-diagnosed by a CONSULTING
arborist, i.e. one with no program to sell you. Go to the ASCA website to
find one in your area. - www.asca-consultants.org.
Mike LaMana, MS
Heartwood Consulting Services, LLC
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