Question
Dear Stephen,
Some three years ago we planted two plants of wisteria sinensis, in the very
south of Sweden. They have done well, and even bloomed. Four days ago they
were both still in good shape, but one morning we saw that one of them had
just collapsed. ALL the leaves were curled up and entirely dry. From top to
bottom. Several branches were also dry. We have seen no significant amount
of animals/insects - except a nest of earwigs. We did notice that several
leaves had collections of dark spots, surrounded by yellowish circles. The
other wisteria seems fine, except it too has dark spots surrounded by
yellowish fields. And earwigs. Acting in something of a panic we sprayed the
collapsed wisteria with the same thing we use for roses. We were given the
advice to cut the tree back significantly, which we have done. The trunk
seems healthy - greenish, and white in the middle. Having scraped the bark
carefully, we see that underneath it is bright green. We have searched for
signs of crown gall down to ca 10 cm below earth level, but have found
nothing.  Both wisterias are planted in planting soil, but the original soil
contains clay. Deeper yet are stones and macadam. We did not find the soil
drenched. Do you have any idea of might have happened, and do you have
any advice about what to do. Thank you so much for your time.
Martin and Roberta
Lund
Sweden

Answer
Martin:
From your description, this plant went from healthy to "graveyard dead" literally overnight.  I doubt seriously if crown gall or any other bona fide infectious disease could do this- as I picture it.  As far as I know earwigs do not do this either. Look closely at the basal portions of the plant looking for any evidence of physical damage--string trimmer etc. that may have damaged the bark. Also, review any potential applications that may have been sprayed directly to or applied to the soil. If the internal tissues are still green, this conditions may be temporary. Wait a few days before you remove.

Another head scratcher for us!

Steve