pine borer beetles tunnel into P. radiata

Here in Sebastopol, Sonoma County, California we are losing many Pinus radiatas. I'm a landscape architect and have not used Monterey Pines in a project for years. We had six of them on our property and had four removed this year. Two were dead and the other two were going fast.

My neighbors are surrounded by what looks to be hundreds of the pines (actually less, but it looks like hundreds) and one can see spots of dead needles scattered among the branches. A couple of the trees are already dead and at least one more is about half brown. I feel sorry for the neighbors as this is an expensive disaster. The trees will have to be removed over time.

The cause is Pine Borer beetles. They bore into the tree and lay eggs under the bark. They also carry a fungus disease from tree to tree.

Around twenty years ago Monterey Pines were a trend here. Their fast growth and easy care made them seem like a perfect solution for windbreaks and screens. People planted them willy-nilly everywhere, usually without much thought. They would then top them when they grew "too tall". The topping stresses the pines, which as it turns out, were already stressed by drought. The result is the attack by the borers.

I think the lesson for us all is not to plant one species of tree predominantly, but to diversify species, and DONT TOP TREES.

Sorry for "yelling" in print, but topping is an epidemic here. Many people plant tall growing trees when they really would like a shorter one. They then chop the poor trees just when they're starting to look good.

One of my favorite shorter substitutes for Pinus radiata is Myrica californica, Pacific Wax Myrtle. It's native to the coast ranges of the North American west coast from S. Calif. to British Columbia, Canada. It gets around 25 feet high and wide unpruned and away from coastal winds. I don't know how it does in other countries. It makes a great screen and windbreak as well as a dark green background for perennials.

Steve French
third year in a new location. Just starting a garden after spending money and time on construction projects.


On Aug 23, 2004, at 7:03 PM, Tony and Moira Ryan wrote:

Bill Grant wrote:
You know that we are losing a lot of our Monterey pines. The disease is
rampant here and most worrisome. None of mine so far are infected, but long
avenues of them are being cut down. I so worry the virus will jump the
Pacific. Have you had any news about this danger? bill grant@ebold.com

I had heard that they were suffering from some disease, but not that the cause was a virus.

I am sure that in view of the enormous importance to NZ of keeping our pines disease-free every precaution will be taken to prevent it ever entering this country.

We have had a few scares in recent years from various insect pests coming ashore, but so far such invasions have been successfully contained.

Moira
--
Tony & Moira Ryan,
Wainuiomata, North Island, NZ.     Pictures of our garden at:-
http://mywebpages.comcast.net/cherie1/Garden/TonyandMoira/index.htm
NEW PICTURES ADDED 4/Feb/2004


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