Weevils vs. The Mile-A-Minute Weed

  • The mile-a-minute weed (Photo courtesy of the USDA)

Sometimes biologists fight foreign
pests with other foreign animals. But that
can be risky because it can create a bigger
problem than the one it’s supposed to solve.
Sabri Ben-Achour reports on one of the latest attempts to stop a weedy pest:

Transcript

Sometimes biologists fight foreign
pests with other foreign animals. But that
can be risky because it can create a bigger
problem than the one it’s supposed to solve.
Sabri Ben-Achour reports on one of the latest attempts to stop
a weedy pest:

On farms, backyards, and rights of way up the Eastern Seaboard a pointy leaved thorny
newcomer is becoming increasingly visible. It’s called mile-a-minute weed.

Bob Trumbule is an entomologist. He leads me through a stream valley north of
Washington DC where blackberries and small trees are being swallowed up by this
invasive vine.

“So now we’re getting into the mile-a-minute here. Basically what it does it, it’s an
annual vine, it grows up and over plants, it smothers them, out competes them for
sunlight, and weighs them down.”

The weed is native to Eastern Asia: China and Japan. It was introduced accidentally in
Pennsylvania in the thirties. From there, it’s spread to seven other states. It prevents new
trees from sprouting in forests. But back in Asia, it’s not a dominating species like it is
here.

Judith Hough-Goldstein is a professor at the University of Delaware.

“Part of the reason is because it doesn’t have anything that’s feeding on it. It’s gonna be
without its predators so it can out-compete other plants.”

Over several years, biologists searched for something that would eat the vine. They
found a tiny, black weevil in China. It feeds on the plant and lays it’s eggs there, keeping
things in check – in Asia.

“Here are the weevils. I’m gonna give you a glimpse of them here in the cup. They look
almost like little ticks. I’m gonna put them down here in the mile a minute weed patch,
and basically what they’ll do – they’re tough little guys – they’ll climb around and in the
past experience have started to feed almost immediately.”

Up close, they look like little anteaters, poking around the leaves with long snouts.

This may sound risky. There are lots of examples where similar approaches have gone
wrong. A parasite was introduced in North America to control gypsymoths. It attacked
native silkmoths. Mississippi catfish farmers used Asian carp to control algae. They got
loose and are taking over the Mississippi River system and threatening the Great Lakes.

And Trumbule admits nobody knows for sure exactly what might happen.

“Any scientist that might say otherwise is not being honest with themselves or the person
asking the question.”

But he says a lot’s been learned since the days when any scientist could introduce a
species on a whim. These days, exhaustive testing and federal permits are required
before anything is released.

That’s why for almost ten years Judith Hough-Goldstein has been trying to determine if
the weevil would eat anything else. Tests were conducted in a U.S. Department of
Agriculture ‘quarantine facility’ with sealed windows and its own re-circulated air supply.

“So what we found was that, in fact, this particular weevil is extremely host specific. The
insect has evolved to depend on the plant.”

So much so that the weevils and larvae actually starved to death rather than feed on other
plants.

In field tests in New Jersey and Delaware, the weevils have decimated mile-a-minute
weed. Some researchers say it’s the most impressive biocontrol they’ve worked with.

For The Environment Report, I’m Sabri Ben-Achour.

Related Links

Westward Ho for the Ash Borer

  • Adult emerald ash borer (Photo by David Cappaert, Michigan State University, courtesy of the Michigan Department of Agriculture)

The emerald ash borer has eaten through
millions of trees in the US and is spreading
west. Erin Toner has more:

Transcript

The emerald ash borer has eaten through
millions of trees in the US and is spreading
west. Erin Toner has more:

For six long years, the tiny metallic-green emerald ash borer has been a killing machine,
starting with millions of ash trees in Michigan and Canada, and then munching its way
into 10 states.

It was recently discovered in Missouri, and now, it’s in Wisconsin.

The prognosis is not good.

Darrell Zastrow is with the Wisconsin Department of Natural Resources.

“Our forests are not typically resilient against non-native species and that is true for
the emerald ash borer. It is generally considered to be a poster child for invasive
species.”

Officials in Wisconsin are doing what everyone else has done – restricting the movement
of firewood and telling people how to protect their trees.

Some promising treatments to fight the emerald ash borer are being tested, but so far,
nothing has worked at keeping the insect from spreading west.

For The Environment Report, I’m Erin Toner.

Related Links

Big Ships Required to Flush

  • A ship discharging its ballast water (Photo courtesy of the US Geological Survey)

Ships should be bringing in fewer unwanted
pests into the Great Lakes. Both Canada and the
U-S are now requiring ships to flush out their
ballast water tanks before entering the lakes.
Tracy Samilton reports:

Transcript

Ships should be bringing in fewer unwanted pests into the Great
Lakes. Both Canada and the U.S. are now requiring ships to flush out their
ballast water tanks before entering the lakes. Tracy Samilton reports:

Ships need to take on ballast water to keep them stable. When they pump in
water from freshwater foreign ports, they also suck up pests.

Since 2006,
Canada has required ships to flush their tanks with salty ocean water
before entering the Great Lakes. The U.S. adopted the requirement at the
start of this year.

Collister Johnson is with the U.S. side of the St.
Lawrence Seaway, which connects the Atlantic Ocean to the Great
Lakes. He says the rule will eliminate almost 99% of freshwater
pests in ballast tanks.

“If they’re exposed to salt water, especially full strength sea water, they
are effectively killed.”

Samilton: “Why didn’t we do this before?”

Johnson: (laughs) “I don’t know.”

It won’t completely eliminate the problem because some aquatic pests can
still survive in the sediment in the bottom of ballast tanks.

For The Environment Report I’m Tracy Samilton.

Related Links

The Incredible, Edible Weed

  • Garlic mustard ranges from eastern Canada, south to Virginia and as far west as Kansas and Nebraska (Photo courtesy of the National Parks Service's Plant Conservation Alliance)

An invasive plant called Garlic Mustard is
taking over forests in the Eastern half of the country,
and it could be causing long term damage. Julie Grant
reports that some people are getting smart in their
efforts to get rid of Garlic Mustard:

Transcript

An invasive plant called Garlic Mustard is
taking over forests in the Eastern half of the country,
and it could be causing long term damage. Julie Grant
reports that some people are getting smart in their
efforts to get rid of Garlic Mustard:

Brad Steman spends a lot of time in the woods. He likes the serenity.
But as we walk through this park, he winces. The entire forest floor is
carpeted with one plant and one plant only: Garlic Mustard.
Thousands of them. The thin green stalks are as tall as our ankles.

Steman calls it “the evil weed.” Its triangle-shaped leaves shade out
wildflowers, so they don’t grow. Even worse, Steman says Garlic
Mustard poisons baby trees.

“So a forest filled with Garlic Mustard you will see very little
regeneration of that forest, very few seedlings, small trees. So
looking down the line, once those large trees start dying off there’s
nothing to replace them. And that now is the greatest threat to our
Eastern forests.”

Steman says every year Garlic Mustard is spreading farther into the
woods. Anywhere the ground is disturbed.

“So here’s a big stand of it along a trail. This is typically where it
starts. This is thick. This is a healthy stand. There’s potential there
for an explosion. So we should probably pull some. I’ll pull some;
you don’t have to pull any.”

Thank goodness he’s doing it – that looks it looks like tedious work.
Steman crouches down and starts pulling them out of the ground,
roots and all. He sprayed herbicide on some of it, and so far this
season he’s filled 35 big garbage bags with Garlic Mustard plants.
He’s sick of weeding. But it doesn’t look like he’s made a dent here.
All along the Eastern half of the US and Canada people are pulling up
Garlic Mustard from parks and just throwing it away. But some
people don’t like this approach.

“All these people are very shortsighted when they’re doing that.”

Peter Gail is a specialist in edible weeds.

“They’re not looking for other alternative uses – creative ways to use these plants that would be
profitable, that would be productive.”

Gail says: “If you can’t beat ‘em, eat ‘em.” People brought Garlic
Mustard to the US in the mid-1800s because they liked it, to eat. And
they even used it for medicine. Yep. That same nasty weed.

Gail says today Garlic Mustard just needs an image makeover.
Some weeds have become big stars in the cooking world. A few
years ago Purselane was just an unwanted vine, with its fleshy, shiny
leaves matted to the ground. Now it’s known as a nutritional
powerhouse, and is the darling of New York and LA eateries. Gail
wants that kind of fame for Garlic Mustard.

“This is a Garlic Mustard Ricotta dip, Garlic Mustard salsa, stuffed Garlic Mustard leaves – these are all things you can do with this stuff. It’s fantastic!”

Garlic Mustard seeds taste like mustard, the leaves taste like garlic
and the roots are reminiscent of horseradish.
Gail says people should go after Garlic Mustard in the parks, but then
they should take it to farm markets to sell.

“My normal statement is that the best way to demoralize weeds is to
eat them.
Because when you eat them they know you like them and they don’t
want to be there anymore, and so they leave.”

(blender sound)

Today Gail decides to blend a pesto using the early spring leaves.
He picks every last Garlic Mustard in his yard to make a batch.

“Well there it is, garlic mustard pesto. And it isn’t bad, is it?”
Julie Grant: “It’s delicious.”

For The Environment Report, I’m Julie Grant.
Gail: “I’ll use that on ravioli tonight.”

Related Links

New Weapon for Tree-Killing Bug

  • Adult emerald ash borer (Photo by David Cappaert, Michigan State University, courtesy of the Michigan Department of Agriculture)

There might be a new weapon to use against a
destructive pest. Rebecca Williams reports the emerald
ash borer has killed more than 30 million ash trees in
eight states and Ontario:

Transcript

There might be a new weapon to use against a
destructive pest. Rebecca Williams reports the emerald
ash borer has killed more than 30 million ash trees in
eight states and Ontario:

No one’s been able to stop the tiny green beetle from killing trees. But
officials are hoping a new insecticide will help.

Researchers at Michigan State University ran trials for one year with a
chemical called Tree-age. In those tests, the insecticide killed all of the
beetles. The state of Michigan has approved the insecticide for use on ash
trees. Indiana, Ohio and West Virginia are also considering it.

Jim Bowes is with the Michigan Department of Agriculture. He says the
emerald ash borer probably can’t be stopped, but the insecticide might
slow the beetle’s spread.

“Nobody here and I don’t think anybody in the federal government at this
point is talking about eradication. I think everybody is talking about how
are we going to coexist?”

Bowes says the insecticide might be able to save trees in your yard, if
the infestation is caught early enough.

For The Environment Report, I’m Rebecca Williams.

Related Links

Pigs Root Out Evil Bugs

  • Apple grower Jim Koan has discovered that baby pigs are best for taking care of fallen wormy apples in his orchard. He says they have very tender noses. The adult pigs like to root around in the dirt and tend to tear up the orchard. (Photo by Rebecca Williams)

There are a lot of insects that love to eat
apples. A harmful insecticide that kills some of
those pests is being phased out. So farmers are
looking for other solutions. Rebecca Williams visits
an apple grower who’s counting on pigs to get some
help with his pest problem:

Transcript

There are a lot of insects that love to eat
apples. A harmful insecticide that kills some of
those pests is being phased out. So farmers are
looking for other solutions. Rebecca Williams visits
an apple grower who’s counting on pigs to get some
help with his pest problem:

(farm animal sounds – turkeys, etc)

The spring rains have started, and at Jim Koan’s pig pen that means mud.

(sound of shoes squishing in mud and piggy snorts)

Of course, these pigs don’t really seem to mind that.

“These Berkshires, you can see, are really friendly, they’re just coming
right up to you.”

Jim Koan really likes his pigs. That’s because he’s hoping the pigs will
take care of one of his worst pests. It’s a beetle called the plum
curculio. In early spring the beetles lay eggs in the little green apples.
The larvae hatch and eat the apples from the inside out.

Then the tree drops the bad wormy apples on the ground. And the worms just
keep on eating.

For a long time, farmers used an insecticide called azinphos-methyl to kill
the beetles. But the Environmental Protection Agency is phasing it out.
That’s because the EPA says the pesticide is very toxic to some wildlife and
it can make farm workers sick.

Jim Koan hasn’t used the pesticide for 10 years, ever since he became an
organic grower. So for years now he’s been trying to find a perfect
predator to stop the beetle larvae.

The chickens were too lazy. Hawks ate the guinea fowl that he tried.

So, finally, Koan says he had a flashback. His grandpa used to have hogs in
the orchard.

“When I would climb up to go up in the tree in the summertime to get a green
apple to eat all the hogs would come running over there and my granddad
always told me you stay away from those hogs they’ll eat you up! I’d be
really scared and be up there for an hour or two until the hogs left again.”

(laughs)

Koan says he knows now that the hogs were just hoping for a snack. So last
year he decided to buy some hogs and see if they would eat the wormy apples
on the ground. He says baby pigs worked best.

“And they’d just go up one row gleaning it, kinda like little vacuum
cleaners (makes sucking sound) and suck up all the apples!”

Koan says the baby pigs ate 98% of the fallen apples with beetle
larvae in them. But he still needed to know that the beetles were actually
gone, so they wouldn’t come back to attack his apples next year.

That job
was up to researchers at Michigan State University. Koan says they fed a
mix of beetle larvae and apples to pigs on campus.

“Then they put diapers on the hogs – truly, diapers!! It was unbelievable.
They took special superglue and velcroed it on their butt so then when they
defecated they caught all that. Then they took these poor students and made
them go through there and wash all that and look for worms.”

Koan says out of 200 worms that were fed to the pigs, they only found one
worm at the other end. That means, so far it looks like pigs are a
pretty good predator.

But the researchers don’t want to let pigs run wild – just yet. David
Epstein is the lead researcher on the project.

“Jim and I are scheming all the time. I have great expectations that this
could be a good management tool in the future but we have to figure out how
to do it properly.”

Epstein says they need to make sure the pigs don’t cause any contamination
problems. Something like E. coli. He says so far there isn’t any
evidence of that, but it’s the kind of thing you have to be sure about.

If this all goes well, the farmer and the scientist will be writing a book
together. It’ll be sort of a self-help book: getting pigs to take care of
what’s bugging you.

For the Environment Report, I’m Rebecca Williams.

Related Links

Tree-Killing Bug Continues to Spread

  • An adult ash borer. The tree-killing bug has now been found in Toronto. (Photo courtesy of the Michigan Department of Agriculture)

Since arriving in North America in the 1990’s, the emerald ash borer
has largely been contained to the upper Midwest. But now scientists say
the destructive beetle is spreading. Noah Ovshinsky has more:

Transcript

Since arriving in North America in the 1990’s, the emerald ash borer
has largely been contained to the upper Midwest. But now scientists say
the destructive beetle is spreading. Noah Ovshinsky has more:



Since the emerald ash bore arrived, the pest has killed more than 20
million ash trees in North America. Canada has by and large been spared
with infestations confined to the extreme southwest of Ontario.


Now, Canadian officials say the bug has traveled more than two hundred
miles to Toronto. Scientists don’t know how many trees have been
infested. Ken Marchant is an ash borer expert with the Canadian Food
Inspection Agency:


“It can be in a tree at undetectable levels and be quit heavy and then
the tree dies and so it’s incredibly difficult to detect at low levels.
Nothing has changed, there’s no traps for it and really no effective
way of surveying for it with any great accuracy.”


The ash borer has now spread across southern Ontario and six states.


For the Environment Report, this is Noah Ovshinsky.

Related Links

Epa to Regulate Bug Zapping Washing Machines

There’s a new generation of washing machines that use charged particles
of silver to kill bacteria. Rebecca Williams reports the Environmental
Protection Agency says it’s going to regulate the machines as
pesticides:

Transcript

There’s a new generation of washing machines that use charged particles
of silver to kill bacteria. Rebecca Williams reports the Environmental
Protection Agency says it’s going to regulate the machines as
pesticides:


The Samsung Silver Ion machine generates tiny charged particles of
silver that kill bacteria on contact.


The EPA has decided any kind of machine that generates ions to kill
pests has to be regulated as a pesticide.


Andrew Maynard is a scientist with the Woodrow Wilson International
Center for Scholars. He says there are worries that these kinds of
machines could kill helpful bacteria:


“What’s causing concern is the release of these charged silver atoms
into the environment which can kill bacteria but also might end up
killing bacteria we don’t want them to.”


Maynard says there are about 130 products on the market now that use
tiny silver particles to kill bacteria. They’re in everything from kitchen
countertops to food containers.


But he says EPA hasn’t decided whether to regulate those products as
pesticides.


For the Environment Report, I’m Rebecca Williams.

Related Links

Co2 Crops Not Tops

  • Theories that crops, such as the corn in Illinois, will benefit from increases in CO2 might not be as good as predicted. (Photo by Scott Bauer, courtesy of the USDA Agricultural Research Service)

Carbon dioxide emissions from our cars and factories are the number one
cause of global warming. Scientists have long theorized that more of
the gas in the atmosphere could actually help farmers grow bigger
plants. But new research from America’s Breadbasket is challenging
that assumption. David Sommerstein reports:

Transcript

Carbon dioxide emissions from our cars and factories are the number one
cause of global warming. Scientists have long theorized that more of
the gas in the atmosphere could actually help farmers grow bigger
plants. But new research from America’s Breadbasket is challenging
that assumption. David Sommerstein reports:


Lin Warfel’s a fourth generation farmer in east-central Illinois. His
fields are flat and endless, the soil chunky and black and just about
the best in the world. An Interstate highway groans on one side of his
cornfield:


“In my career, early on, there was no Interstate past my farm.”


As traffic increased over the years, Warfel noticed a strange
phenomenon. The crops closer to the Interstate grew bigger than those
further away:


“They respond to the carbon dioxide. They can stay greener longer than
plants out into the field.”


OK… so, here’s a high school biology reminder: carbon dioxide, along
with water and sun, is an ingredient in photosynthesis, which makes
plants grow.


Increasing carbon dioxide in the atmosphere is also the biggest cause
of global warming. So scientists thought, huh, more carbon dioxide in
the atmosphere, bigger crops. They even coined a term: the “carbon
dioxide fertilization effect:”


“The effects of CO2 on crop yields are fairly well-understood.”


The Department of Energy’s Jeff Amthor has studied this stuff since the
1980s:


“We would expect that by the year 2050, that the increase in CO2 alone
would probably increase yields by about 10 to 15% in soybean, wheat and
rice relative to today’s yield, with nothing else changing.”


Other things are changing, like hotter temperatures and more drought.
But the predominant thinking has been that the increased carbon dioxide
will moderate those negative factors, maybe even outweigh them. A
recent study by the American Economic Review concluded U.S. agriculture
profits will grow by more than a billion dollars over the next century,
due to global warming. Most of this is based on experiments done in
controlled, greenhouse conditions, but new research done in real fields
is challenging the assumptions:


“Where you’re standing is what we refer to as our global change
research facility on the south farms of the University of Illinois.”


That’s biologist Steve Long. He runs what’s called the SoyFACE project
at the University of Illinois in Champaign-Urbana. Here, Long can
actually pipe carbon dioxide gas out to the fields, and grow real crops
in an atmosphere of the future.


Long strolls out to one of 16 test plots and stop at a white pipe
sticking out of the ground:


“This is one of the pipes where the carbon dioxide actually comes up
and then it will go out into the field here.”


The carbon dioxide pipes circle a plot about the size of a tennis
court. They release the gas over the crops. Computers monitor the air
to keep the concentrations steady:


“And the current atmospheric concentration of carbon dioxide is about
380 parts per million. We’re raising that to the level which is
expected for the year 2050, which is about 550 parts per million.”


Long has grown the crops of 2050 for 5 years now. His results
shocked him. The plants did grow bigger. They survived longer
into the fall, but the yields were 50% lower than expected. And
pests thrived. The Western corn rootworm, for example, laid
twice as many eggs:


“Japanese beetle, which eats quite a lot of the leaves of soybeans, do
twice as well under these elevated CO2 conditions. They live longer. They
produce many more young. The yield increases we’ve seen could start to be
counteracted by those increased pest problems.”


Long’s results found supporters and critics when published in
Science magazine last summer. Some researchers say extra CO2
could hurt agriculture more than it helps because weeds become more
aggressive.


The Department of Energy’s Jeff Amthor co-wrote a paper challenging the
interpretation of Long’s data. But he agrees more work needs to be
done in real-life conditions:


“The bigger questions that are now before us are the interactions of CO2 with
warming and change in precip, changes in weed communities, changes in
insect communities, changes in disease outbreak. There are a lot more
questions there than there are answers.”


Amthor says what’s at stake is our future food supply.


For The Environment Report, I’m David Sommerstein.

Related Links

Interview: The Future of Water in a Warmer World

  • Peter H. Gleick, President and co-founder of the Pacific Institute, is concerned that without reducing greenhouse gas emissions, global warming will have dire impact on water resources. (Courtesy of the Pacific Institute)

With concern about climate change growing, some scientists are trying to determine how global warming will affect sources of water. Lester Graham spoke with the President of the Pacific Institute, Peter Gleick about what climate change might mean to weather patterns:

Transcript

With concern about climate change growing, some scientists are trying to determine how global warming will affect sources of water.

Lester Graham spoke with the President of the Pacific Institute, Peter Gleick about what climate change might mean to weather

patterns:


PG: Overall, the planet is gonna get wetter because as it gets hotter, we’ll see more
evaporation. The problem is, we aren’t always gonna get rain where we want it.
Sometimes we’re gonna get rain where we don’t want it. And at the moment it looks like
the biggest increases in rainfall will be in the northern regions where typically water is
less of a problem. Or at least water quantity is less of a problem. And we may actually get
less rainfall in the Southwest where we need it more.


LG: Let’s talk about some of the precious areas to North America. For instance, a lot of
people are worried about snow pack in the Rockies.


PG: Yes, well, one of the most certain impacts of global climate change is going to be
significant changes in snowfall and snowmelt patterns in the western United States as a
whole, actually in the United States as a whole because as it warms up, what falls out of
the atmosphere is going to be rain and not snow. Now that really matters in the Western
United States, in the Rocky Mountains and the Sierra Nevada where our snow pack really
forms the basis of our water supply system. Unfortunately, as the climate is changing,
we’re seeing rising temperatures and decreasing snow pack. More of what falls in the
mountains is falling as rain, less of it’s going to be snow. That’s going to wreck havoc on
our management system, the reservoirs that we’ve built to deal with these variations in
climate. Incidentally, it’s also going to ruin the ski season eventually.


LG: You mentioned that the farther north you go, according to some models, we’ll see
more rain or more precipitation. At the same time, with warmer temperatures, we’ll see
less ice covering some of the inland lakes, such as the Great Lakes, which means more
evaporation. So, what are we going to see as far as those surface waters sources across
the continent?


PG: Without a doubt, global climate is changing. And it’s going to get worse and worse
as humans put more and more greenhouse gases in the atmosphere. And as it gets
warmer, we’re going to see more evaporation off of the surface of all kinds of lakes,
including especially the Great Lakes. And interestingly, even though we don’t have a
great degree of confidence of what’s going to happen precisely with precipitation in the
Great Lakes, all of the models seem to agree that over time, the Great Lakes levels are
going to drop. And it looks like we’re going to lose more water out of the surface of the
Great Lakes from increased evaporation off the lakes than we’re likely to get from
precipitation, even if precipitation goes up somewhat. And I think that’s a great worry for
homeowners and industry around the margin of the lake. Ultimately for navigation,
ultimately for water supply.


LG: There’s a lot of talk about the gloom and doom scenarios of global warming, but
they’ll be longer growing seasons and we’re also going to be seeing, as the zones change,
more of this fertile ground in as northern US and Canada get longer growing seasons.
That’s not a bad thing.


PG: There are going to be winners and loser from global climate change. And
interestingly, there are going to be winners and losers at different times. Certainly, a
longer growing season is a possibility as it warms up. And I think that, in the short term,
could prove to be beneficial for certain agriculture in certain regions. Interestingly
though, and perhaps a little depressingly, over time, if the globe continues to warm up, if
the globe continues to warm up, evidence suggest that the short term improvements in
agriculture that we might see might ultimately be wiped out. As it gets hotter and hotter,
some crop yields will go down after they go up. We’re going to see an increase in pests
that we didn’t used to see because of warmer weather. Unfortunately, pests like warmer
weather. Furthermore, if we don’t really get a handle on greenhouse gas emissions, if we
don’t really start to cut the severity of the climate changes that we’re going to see, the
doom and gloom scenarios unfortunately get more likely. Over time, the temperatures go
up not just one or two or three degrees Celsius but four or five or eight degree Celsius.
And that truly is a catastrophe for the kind of systems we’ve set up around the planet.


HOST TAG: Peter Gleick is a water expert and President of the Pacific Institute for Studies in Development, Environment and Security, based in California.

Related Links