causes defoliation in mature plants, kills seedlings and destroying or
preventing the formation of flower spikes. H. Transversouittatus appears to be a
very likely candidate as a biological control agent for purple loosestrife but
several years of trials will be necessary to determine it’s effectiveness. It
could take up to ten years to show it’s full potential.
Galerucella Calmariensis and Galerucella Pusilla can be classified together
because they are both leaf feeding beetles that have similar life histories,
occupy the same habitat and affect purple loosestrife in the same manner. These
two species are often found together in Northern Europe with one of the species
dominating destruction of the stand. G. Calmariensis extends farther north than
G. Pusilla and will be better suited for Canada’s northern sites of purple
loosestrife. Both species are parasites which have good host finding
capabilities. Females will move from one host to the next, once a certain level
of feeding damage has been reached, this guarantees the spread of the attack in
large purple loosestrife stands. After being put through the same tests as H.
Transversouitatus, Galerucella Calmariensis and Galerucella Pusilla were found
to be extremely host specific and do not pose a threat to native species in
Canada. In Europe these beetles are more commonly found than H.
Transversouitatus.All three of these insects appear to be very promising in
their control over purple loosestrife stands but, as mentioned earlier, it could
take a few years to notice any progress. The idea of introducing another species
to Canada’s wetland ecosystem is not approved by all due to the purple
loosestrife infestation incident. Many believe that tampering with nature is
what has caused the problems in the first place and hopefully by letting nature
run it’s course all will turn out for the best . Unfortunately this viewpoint
can not be supported for long. Canada is at a point right now that without the
biological control agents, purple loosestrfie will destroy a lot of wetland and
farmland. With biological control we can only hope that the ecosystems can be
brought back under control.
Purple loosestrife is a very serious problem. It’s rapid invasion is threatening
wetlands, waterfowl and fisheries as well as the diversity of Canada’s flora and
fauna. If this plant is not brought under control quickly then the result of
this exotic species being brought to Canada could be disastrous. The use of
cultural and chemical control has not been effective so we now rely on the
success of biological control to stop the spread of this hardy invasive plant
and to replenish the diversity of Canada’s wetland ecosystem. As a country we
must do everything we can to reduce the spread and growth of purple loosestrife.
As a concerned Canadian you can report any local purple loosestrife stands,
spread your knowledge about the problem, strongly discourage the plantings of
any new plants or the selling of the weed in nurseries and join the Ontario
Federation of Anglers and Hunters. By doing this you are donating money and
support the tests that are being conducted. We must work together to remove the
purple blanket that silences our wetlands.
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