Pine wilt, caused by the pinewood nematode, was discussed in issue No. 8 of
Home, Yard and Garden Pest Newsletter. We have
confirmed several cases
of pine wilt at the Plant Clinic in the last two weeks, so
it is appropriate to review the symptoms of this
disease. Trees dying now were likely infected in spring
or summer.
Watch for the appearance of entire dead
branches or sudden decline and death of an entire pine
within
a few weeks or months of initial symptoms. Be
particularly suspicious of 15- to 20-year-old Scotch
pines with these symptoms. Austrian pine is the
only species that may show tip dieback as the first
symptom. For symptoms on white pine, see issue No. 12
of this newsletter. (Although we have assayed many white
pines for pinewood nematodes, we have
never confirmed the pinewood nematode in that species.)
Sawyer beetles vector the nematode from pine
to pine. Because there is no easy way to stop the
beetle and because no treatments exist for infected
trees, early detection is critical to disease control. To
break the disease cycle, quick removal of an infected tree
is important. Consult Report on Plant Diseases
No. 1104 for details about pine wilt.
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