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Every so often, a damaging insect comes along that is so severe it has the potential to wipe out a species. The Bronze Birch Borer is one of those.

It has been in the Northwest for almost a decade but is gaining momentum.  This pest is small but severe. It kills a birch tree by eating the conductive tissue under the bark, thus cutting the root off from the branches. If left untreated, this will kill the tree within a few years. If you have any type of birch trees, please keep an eye on them.

This pest will target trees under stress. One of the primary reasons for stress is drought and the resulting slow growth. It is suprising how dry the soil may become within the drip line area. Even with regular summer watering, roots may become much dryer than you think. I myself was suprised to find that the soil in the drip line region in my own landscape was bone dry even though I have a sprinkler system. Birches are thirsty plants, often native to moist lowlands. This is the kind of stress that can trigger an attack. The bottom line is water more, and check the soil now and then.

To protect or begin the control process for Bronze Birch Borer, the trees must be treated with an approved soil active systemic product during the cool months, which is then absorbed by the root system in the early Spring. Not all systemic products will work. Most 'over-the-counter' Rose type systemics will do nothing. Foliar spray treatments will do little. Because this pest is so severe I recommend preventative treatments yearly. If the pest invades to the point of severe damage, it may be too late.

If you have Birch trees please contact us for an evaluation for Bronze Birch Borer. We have the proper material and equipment for treatment.

Steve

Photos: Above-the crown of the birch tree, or just one side of it, will often begin to die first. Left: The adult Bronze Birch Borer leaves a distinctive 'D'-shaped exit hole as it burrows out of the tree. Many times, the area around the exit hole is stained this bronze color.