Magnolia Problems

[arbornature]

I've inspected Magnolia (18 years old or so); it has tip borers as well as small infestation of scale. However, I have heard that large amounts of boron in the water could do that damage (which you can see in the pictures). The tree looked healthy in the beginning of the year; but started to progress quickly at the end of it.

Have you dealt with boron damages in the past?

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[Urban Forester]

That looks alot like old herbicide injury. A HIGHLY systemic herbicide at that. A lack of Boron would give a magnolia a chlorotic look. I've never seen the effects of an "over-dose" of Boron, but if salt based, the damage could appear as marginal dessication, I suppose. I think I'm sticking w/herbicide.

 

[beastmaster]

Are other near by plants and trees effected also. Is the tree near a train tracks or power utility? A soil and foliar analysis would maybe answer or at lest eliminate and narrow down possible causes. Magnolias are very sensitive to boron, and it shows up in the older growth. A water test might not hurt either if its important.
Has there been any use of herbicide near the tree?