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On July 16th, 1999 Partnership members Mike Grisar and Fred Rompelman
released up to 15,000 leaf eating, Galerucella calmariensis, beetles
in Ulao Creek to help control infestations of Purple Loosestrife.
Past results of the beetles’ work has been very encouraging.
These beetles have done extensive damage exclusively to purple
loosestrife.
Fred and Garrett Rompelman
raised the beetles in the family’s yard on behalf of the Ulao Creek
Partnership. The Partnership is
hoping the beetles will help to control Purple Loosestrife and curb its spread.
The beetles eat the loosestrife leaves and damage the flowers resulting
in less seed production. Less seeds is an important step in controlling loosestrife,
since each flower stalk can produce 100,000 seeds!
Purple Loosestrife is a perennial herb native to
Europe that has become established in many North American wetlands.
It can be identified by its large purple flowering spike, which blooms
from mid-July through mid-September.
North American loosestrife
populations are invasive, and once established, can quickly form dense stands
that displace native plant species. One
reason that Purple Loosestrife out-competes North American flora may be that it
has no natural enemies.
The U.S. Department of
Agriculture has approved Galerucella calmariensis, along with three other
insects native to Europe, for release in the United States.
These insects feed exclusively on Purple Loosestrife.
Although biological control will not eradicate purple loosestrife
entirely, preliminary results suggest that these insects may reduce purple
loosestrife infestations by as much as 90%.
At the time of insect release, site
characteristics including habitat and soil type, size of infestation and water
levels are recorded. Follow-up
visits to the site occur later in that season, and in subsequent years, so that
survival and establishment of the beetles can be assessed and their impact on
the plant population evaluated.
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