Question
I live in North Dakota.  We planted a weeping birch in our yard the year 26 yrs ago.  It is a beautiful tree.  Has never had birch bore that we know of.  Each year it seems to produce seeds earlier and more of them.  This year has been terrible.  Is this normal or is there something we should be doing?
For the last several years we have had a local tree service inject the tree with something (I do not know what it is) to prevent birch bore.  This year we did not do that as last year they charged us $180 for the injection (usually 6 vials are injected into trunk that take about 8 hours to be absorbed).  Is that an unreasonable cost or should we bite the bullet and go ahead with it again this year?  Is there a particular time of year this should be given?  Is there something we can do ourselves to prevent birch bore?
Thank you for any help.  This is a huge magnificent full healthy appearing tree and I want to do anything to keep it that way.

Answer
Control The best control for bronze birch borer is to maintain a healthy tree as the borer larvae cannot live in healthy vigorously growing trees. This means sufficient watering! Because of the birch tree's high water use, fall and spring pruning are not recommended for birch trees. The wounds resulting from improperly timed pruning may bleed enough sap, that branches higher on the tree will be drought stressed. Yellow-bellied sapsucker and woodpecker injury may also induce drought condition, resulting in top dieback if their holes girdle the trunk.

It is possible to prevent the adults from laying eggs by spraying the top and trunk of the tree with chlorpyrifos (Dursban) in June. Repeat twice at 3-week intervals.
Two or three trunk sprays with Dursban during spring and early summer generally work well for borer control. While a number of products are labeled for 揵orers?on trees in home landscapes, it is unclear just how effective these materials will be on specific insects like ash lilac, flatheaded and roundheaded appletree borers. One product that lists both flatheaded and roundheaded borers on its label is Bayer Advanced Tree and Shrub Insect Control. The active ingredient in this product is imidacloprid, a systemic, soil applied insecticide which is taken up by tree roots. Although imidacloprid is long acting once inside the plant, it must be applied well in advance of the expected infestation to be effective.