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strate the advantage of a white list over a banned list.</div><div><br>&
On 10/26/2010 8:27 AM, Randy Lauff wrote:
>
> I am, however, confident that any of the jobs you've attributed to [Purple Loosestrife]
> can be done by native plants. And, you have conveniently overlooked
> their ability to dominate wetlands. Perhaps a drive to Ottawa, through
> Quebec would convince you...I did this this summer. Loosestrife has not
> only invaded huge areas, it I fear, has won.
* this thread has been fascinating, and I haven't been sure I had
anything to add, though there have been thoughts about the question if
some plants become invasive just because they've only been introduced a
few times, and haven't brought their pests along through multiple
introductions, as widely introduced species such as Apples have.
This summer we were very impressed by how sparse Purple Loosestrife was
in New Brunswick and Nova Scotia, in comparison to southern Ontario and
Quebec, where Purple Loosestrife has been "controlled" by the
introduction of Galerucella Beetles, and is much less widespread than it
was before 2004. You can recognize Loosestrife that's been hammered by
Galerucella by the holes in the leaves and the twisted and forked
character of the stems.
This summer, after an irregular spring, herbivorous Insects in general
did poorly in eastern Ontario, and the Loosestrife "got away from" the
Beetles. Many places where Loosestrife hadn't flowered for some years
were again purple. My conclusion is that these were plants that had
previously been suppressed by the Beetles, but not killed, in previous
years, so that the extent of Loosestrife hasn't yet come to equilibrium
with the presence of Galerucella.
I think that in another decade a lot of these wounded plants will have
died, and that in a year when herbivorous Insects don't thrive, there
won't be such a resurgence of bloom as we saw this summer.
fred schueler
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Frederick W. Schueler & Aleta Karstad
Bishops Mills Natural History Centre - http://pinicola.ca/bmnhc.htm
now in the field on the Thirty Years Later Expedition -
http://fragileinheritance.org/projects/thirty/thirtyintro.htm
Daily Paintings - http://karstaddailypaintings.blogspot.com/
RR#2 Bishops Mills, Ontario, Canada K0G 1T0
on the Smiths Falls Limestone Plain 44* 52'N 75* 42'W
(613)258-3107 <bckcdb at istar.ca> http://pinicola.ca/
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