Purple loosestrife is a beautiful plant. It’s tall… and each cone-shaped stem produces hundreds of flowers. When the plants bloom in mid-summer they can create a sea of purple in wetlands throughout the region, but the ability of the plant to spread and reproduce in great numbers is what concerns scientists and land managers. Over the years they have been working to control it. The Great Lakes Radio Consortium’s Mark Brush says one way they’re trying to control it is by releasing a bug to eat the plant:
Purple Loosestrife is a beautiful plant. It’s tall… and each cone-shaped
stem produces hundreds of flowers. When the plants bloom
in mid-summer they can create a sea of purple in wetlands
throughout the region… but the ability of the plant to spread and
reproduce in great numbers is what concerns scientists and land
managers. Over the years, they have been working to control it.
The Great Lakes Radio Consortium’s Mark Brush says one way
they’re trying to control it is by releasing a bug to eat the plant:
Roger Sutherland has lived next to this wetland for more than 35
He helped build a boardwalk over the soggy marsh so that he can
get a close-up view of some of his favorite plants:
“You see that plant with the big green flower? Yep. That… and
there’s more along here… that’s a pitcher plant. These are insect
eating plants and there’s another one called sundew here… here’s
some right in here…”
But like many wetlands throughout the country, this wetland has
been invaded by a plant originally found in Europe and Asia.
Purple Loosestrife was introduced as an ornamental plant.
It was a
beautiful addition to gardens, but once it took
hold in the environment,
it out-competed native plants.
Frogs, birds, and insects have relied on these native plants for
thousands of years. Purple Loosestrife is crowding out their habitat.
“We’re going to get a lot more shade with this loosestrife.. and so
these plants that are on these hummocks here…
these little insect
eating plants and so on… just can’t tolerate that shade, so we’ll
probably lose ’em unless I can keep it open here… and I am trying
to keep some of it open.”
The plant spreads quickly… that’s because one plant can produce
more than two million seeds that spread with the wind, like dust.
So when it moves into an area, it often takes over creating a thicket
of purple with a dense root system.
Land managers have seen populations of ducks, and turtles
disappear when loosestrife takes over…
And research has shown that the plant can reduce some frog and
salamander populations by as much as half.
So land managers wondered what to do to stop the spread of this
They initially tried to control the plant by digging it up… or by
applying herbicide to each plant.
Trying to kill the plants one by one is hard work… especially
considering how abundant purple loosestrife is.
But researchers have hope because of a bug.
(Sound of volunteers planting loosestrife)
Volunteers have gathered here in Ann Arbor, Michigan to plant
They’re putting dormant loosestrife roots into potting containers and
When the plants leaf out they’ll be covered with a fine mesh net and
become home to a leaf-eating beetle known as galerucella.
And galerucella loves to munch on purple loosestrife.
The volunteers are creating a nursery to raise more beetles.
Once they’ve got a bunch of beetles growing on the plant… they’ll
take it to a nearby wetland… and the bugs will be released into the
Linda Coughenour is a member of the Audubon Society.
Her group is working with state and local agencies to raise and
release these beetles.
She says tackling purple loosestrife invasions is a big task – and
governments need help from volunteers to deal with the problem:
“This is a serious problem throughout the entire Great Lakes
wetlands… it has migrated from the East Coast to the Midwest…
so, uh.. the problem’s just too big – so they thought up doing this
volunteer project and they’ve enlisted people all over the state… and
we’re just one of those.”
Volunteers have have been releasing their beetles into this wetland
for few years now and they’re beginning to see progress:
“It’s going really well… for a while we got off to a slow start, but for two
years now we’ve found evidence that the beetles are reproducing on their
own. We see little egg masses, we see larva that are starting to eat
the plants, we see adult beetles on the plants that have wintered
over. And that’s the thing, to get them to do it on their own.”
But releasing a foreign species into the wild is always a concern.
There are a number of examples of bugs released into the wild to
eliminate a pest, but ended up causing a problem themselves.
But before importing a bug that will prey on plants – the federal
government requires testing to make sure it won’t eat other plants.
The tests have been done.
And researchers feel that this is an extremely finicky bug…
Berndt Blossey is a specialist on invasive plants and ways to control
He says the beetles were tested on native plants before they were
allowed to import the bugs:
“And it was shown there that they will not be able to feed and
develop on the plants. They will occasionally nibble on them, but
they will not be able to develop on them and they usually move off
after they have taken a bite, and they move off to other plants.”
The leaf beetle is not the only bug researchers are importing.
They’re also importing two other beetles known as “weevils.”
One that feeds on loosestrife flowers, and one that feeds on its root
Blossey says more than one bug is needed to keep the plant from
“Loosestrife will rebound from resources in the root stock. If you
have the root feeder in the system as well, these fluctuations will be
dampened, so loosestrife will not be allowed to comeback to higher
(sound of wetland up)
People who admire the diversity of plants and animals in wetlands
like the idea of keeping purple loosestrife in check.
Roger Sutherland welcomes the bugs.
He believes they’ll help him keep this wetland open for the plants,
birds, and insects he’s come to know over the years:
“We know that the purple loosestrife will probably always be here.
But if we can bring it down to a manageable level, where you’re going
to have a pocket here and a pocket there… and you can kind of
maintain the integrity of this wetland system… then you can’t ask for
anything more than that.”
And researchers say that’s the goal.
To help these wetlands reach a balance… so that plants and animals
that have evolved to rely on these wetlands for thousands of years…
can continue to do so.
For the Great Lakes Radio Consortium, I’m Mark Brush.