Invasive Plant News

This summer keep a lookout for common buckthorn (Rhamnus cathartica) trees with witches’ broom or yellows disease symptoms.  If

Symptom: Red or Yellow Leaf

witches’ broom is present in North America already, it may indicate a potential biocontrol for invasive species of buckthorn.  Witches’ broom is a symptom

Symptom: Deformed and Crinkled Leaf

of phytoplasma disease.  It was detected in potential biocontrol insects and Rhamnus species in Europe. It has not been reported in in North America. This flyer has details and photos showing what the leaves would look like if they have a phytoplasma disease: Have You Seen a Buckthorn Tree with These Symptoms??

Send reports to Dr. Roger Becker of the University of Minnesota.  Email: becke003ATumn.edu.  (Note: @ sign removed to reduce spam.)

Nineteen ecologists argue in an article in the recent issue of Nature that too many in the field of “invasion biology” have an unjustified bias against non-native speices.  The group of nineteen contends that this bias against non-native species is based in ideology rather than science.  Science Daily has a good summary of the piece.

My question regarding the Nature article is this: Why is bias against non-native species bad?  One concrete example on everyone’s minds here in Minnesota involves the native ash tree.  We have

Emerald Ash Borer

more ash trees here than anywhere else in the country – nearly one billion.   The emerald ash borer, an invasive species, threatens them.  I was just walking down a street lined with ash trees a couple days ago when the temperature topped 100 F.  I want those ash trees to live.  The effects on ecosystems will be devastating.  University of Minnesota forest ecologist Lee Frelich in an article in Minnesota Conservation Volunteer cites the impending loss of the hundreds of millions of black ash trees that line wetlands in our northern forests.  According to Frelich, if the beetles destroy those trees, habitat for wildflowers, butterflies, songbirds, herons, owls, woodpeckers, moose will be changed forever.

Now our state and others are spending millions of dollars to prevent the spread of the ash borer.  Three points: First, wouldn’t it have been wonderful if an even stronger bias had prevented the ash borer from ever coming to this continent in the first place?  Second, now that it is here, doesn’t it make sense to spend the money to prevent the uncontrolled spread of the ash borer?  Third, the debate in this state has rarely been ideological.  In fact, I have not heard criticism from those in the invasion biology field or the general public of Minnesota’s decision to introduce – after thorough scientific testing – another non-native species, the stingless wasp, to combat the spread of the emerald ash borer.

Since April, 2011, Congress has been considering legislation that effectively overrules a 2009 decision by a federal appeals court in the case of National Cotton Council of America v. United States Environmental Protection Agency.  The legislation concerns applications of pesticides to rivers, lakes, and other waters.  The bill would exempt those pesticide applications from the permitting requirements of the Clean Water Act (or any other law) so long as the pesticide application complies with federal pesticide laws.

Why is this issue so important?  At the heart of the matter are two issues: ecosystem management and local control.  The federal legislation places harmful limitations on both of these.  How?

Pesticides are registered for use in the United States under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).  The Environmental Protection Agency (EPA) registers a pesticide for use if it finds that the pesticide, when used according to “widespread and commonly recognized practice . . . will not generally cause unreasonably adverse effects on the environment.”  7 U.S.C. Section 136a(c)(5)(D).  Note the words in these FIFRA phrases: “widespread,” “commonly,” and “generally.”  The federal pesticide law is not designed to take into account the local situation – the native ecosystem – in a township, city, county or even state.  This means a pesticide can be registered for use . . . even if it “only” has unreasonable adverse effects on the environment on a localized basis.

Permits under the Clean Water Act – which are often issued by state authorities – can help take into account local environmental conditions.  For example, it may make sense to have different rules for pesticide applications to pristine Lake Tahoe versus applications to a temporary wetland in the middle of a corn field in Minnesota or Iowa.

I have written my Senator, Amy Klobuchar, about this issue.  An article from the National Association of Exotic Pest Plant Councils lists key U.S. senators and provides a balanced look at what proponents and opponents of the legislation are saying.