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Global Invasive Species Team listserve digest #120
Fri Sep 12 2003

1. Mixing glyphosate with lake water (Oregon, USA)
2. Economic impact of invasive plants on forestry (Oregon, USA)
3. Herbicides and Johnsongrass (Nationwide, USA)
4. Hawaiian invasion document on line (Hawaii, USA)
5. Native plant exchange (Nationwide, USA)
6. Native Phragmites on Lake Ontario (New York, USA)
7. Japanese knotweed and Japanese beetles (New York, USA)
8. Japanese beetles as biocontrol (Global, Planet Earth)
9. Ailanthus webworm (Nationwide, USA)
10. Literature reviews galore (Global, Planet Earth)


1. Mixing glyphosate with lake water (Oregon, USA)
From: Jonathan Soll (jsoll(at)tnc.org)

In response to Curtis Hutto's question on mixing glyphosate with
river/lake water:

I would urge caution in using lake or river water with glyphosate.
Glyphosate binds strongly to organic matter and soil, especially soil with
good phosphorous bonding capability like most clays. At the least use a
particulate filter or even better a drinking water-type filter. If you
must use lake/river water I would use the maximum rate of glyphosate


2. Economic impact of invasive plants on forestry (Oregon, USA)
From: Jonathan Soll (jsoll(at)tnc.org)

In response to Ellen Jacquart's quest for information on the economic
impact of invasive plants on forestry... I don't know much about forestry
in Illinois, etc., but here in Oregon, in a study commissioned by the
Department of Agriculture, it was estimated that scots (scotch) broom
(Cytisus scoparius) costs the state $80 MILLION/year in lost forest


3. Herbicides and Johnsongrass (Nationwide, USA)
From: Al Tasker (alan.v.tasker(at)aphis.usda.gov)

Concerning the query regarding herbicides and Johnsongrass (Sorghum
halepense) in the last digest, the graminicides like Poast (sethoxydim) or
Fusilade (fluazifop-p-butyl) are much more effective, but you need higher
rates than for annual grass, and need the proper adjuvants.


4. Hawaiian invasion document on line (Hawaii, USA)
From: Barry Rice (bamrice(at)ucdavis.edu)

The 1992 report, "The Alien Pest Species Invasion in Hawaii: Background
Study and Recommendations for Interagency Planning," is now on line in pdf
format at:


It is a great document on interagency planning. The document is being
maintained and updated by the great folks at HEAR (Hawaiian Ecosystems at
Risk project)


5. Native plant exchange (Nationwide, USA)
From: Barry Rice (bamrice(at)ucdavis.edu)

Michael Powelson (TNC, NW Division), contacted us because he is looking
for any examples of agreements between TNC and USFS (or BLM) for
exchanging/sharing native plant materials. Have you used such an
agreement yourself or know of such a thing?


6. Native phragmites on Lake Ontario (New York, USA)
From: Sandy Bonanno (sbonanno(at)tnc.org)

I was in the field recently with Dr. Bernd Blossey (Cornell
University/biological control expert) and students in search of native
biotypes of Phragmites australis in the eastern Lake Ontario region. We
found plenty of exotic phragmites that day, but we now also know of five
eastern Lake Ontario area sites with native phragmites, some that also
support exotic phragmites, some without the exotic. We found in on medium
fens over deep peat, in a fen along railroad tracks, mixed with cattails
in marshes, and on a streamside surrounded by cattails; sites were in Lake
Ontario coastal marshes as well as inland wetlands. At one inland salt
marsh in central NY, it is mixed with and surrounded by purple loosestrife
as well as clones of exotic phragmites.

The native biotypes exhibit a diffuse distribution, often scattered among
other marsh species, and individual stems with floppy foliage; the exotic
is often present in mono-specific, dome-shaped clonal or clone-like
patches; and individuals have stiffly erect leaves. The native one can be
recognized by its red stems; the exotic has pale green or tan stems,
although decumbent stems or exposed rhizomes may be red in either variant.
Leaf sheaths are loose on the native, tightly held, even on old stems, on
the exotic. Stems, especially just above the nodes, are smooth on the
native, ribbed on the exotic. The native one supports a suite of inverts
that have yet to be seen on the exotic, even when both appear in the same

Blossey has a web site that includes the specifics:

Click on Phragmites diagnostic service, then morphological characters for
an illustrated chart comparing the two.

Since many of us spend an inordinate amount of time losing sleep over,
planning for, and implementing management strategies for invasive species,
it's a real thrill to find out that some of the stuff we've fretted about
should be protected instead of killed! I hope this little narrative will
opening your eyes to look for it in your travels as well - and tell
Blossey if you find it (bb22(at)cornell.edu). He thinks it's rare, ought to
be tracked and cosseted the way we do other rare species. Some of us old
dogs have new tricks to learn if that's going to happen!!


7. Japanese knotweed and Japanese beetles (New York, USA)
From: Aaron Schlechter (aschlechter(at)tnc.org)

Last weekend, I was out on Long Island and I observed Japanese beetles
decimating a patch of Japanese knotweed (Polygonum cuspidatum). The
leaves were their primary target and caused the same style of leaf
skeletonization that is commonly seen in gardens. The patch under attack
hadn't flowered, though other local patches were in flower. Has anyone
seen this before? Any thoughts on controlling this plant with a
"bag-a-bug" trap minus the bag? I was very excited to see this and hope
that we may be able to add this pest to the toolbox of invasive plant
control tools.

**Interested readers should check out the next posting --Editor


8. Japanese beetles as biocontrol (Global, Planet Earth)
From: Tunyalee Martin (tamorisawa(at)ucdavis.edu)

I'm always excited to hear about people proposing alternative control
measures! Unfortunately, Japanese beetle, Popillia japonica, is itself a
non-native pest in the eastern US. The adults feed on over 300 different
plants and the larvae, sometimes called grubs, are pests in turf and
lawns. Efforts to control Japanese beetle are estimated at $460
million/year. APHIS (the Animal and Plant Health Inspection Service of
the USDA) has strict quarantines on the movement of plants and soil that
may be infested with Japanese beetle from infested states to those that
are uninfested (see map at www.aphis.usda.gov/ppq/maps/jbmap.html).

To avoid such impacts on non-target species, biological control agents are
tested to determine host specificity before they are released. The
generalist eating habits of the Japanese beetle would make it fail such


9. Ailanthus webworm (Nationwide, USA)
From: Tunyalee Martin (tamorisawa(at)ucdavis.edu)

In the previous listserve digest, Robert O'Neill reported on his
observations of a kind of caterpillar he saw feeding on Ailanthus
altissima (tree of heaven).

>From Robert's description, the caterpillar is almost certainly Atteva
punctella (Lepidoptera: Yponomeutidae - ermine moths), also called the
ailanthus webworm. It is commonly found in the eastern and southeastern
US. Adult moths have brightly patterned wings that are red, black and
yellow. The adults are 2-3 cm (0.75-1.25 inches) long. The larvae are
covered with short hairs and have alternating white and green stripes on
their sides. Along the back is a wide greenish-brown stripe.

The larvae are reported to feed on Ailanthus altissima and the paradise
tree (the latter is probably a reference to the North American native
Simarouba glauca). The larvae spin webbing to pull together 2 or 3
leaflets, producing a nest that may contain several larvae. Once all the
leaves are consumed, the larvae may feed on stem tissue, seriously
damaging seedlings, suckers, and saplings. However, this high level of
damage is rare.

For more information, you can look at the following web sites that I used
in researching the above summary. You may have to cut/paste the longer
urls into your web browser in sections.



10. Literature reviews galore (Global, Planet Earth)
From: John Randall (jarandall(at)ucdavis.edu)

***Two papers appeared in the journal Nature this winter providing support
for the Enemy Release Hypothesis (ERH) which posits that release from
natural enemies (predators, parasites and pathogens) allows some
non-native species to become abundant and aggressive pests in their new
ranges. Also, Keith Clay's nice summary of the topic and of the findings
reported in these two articles appears in the same issue of Nature. (Clay,
K. 2003. Parasites lost. Nature 421: 585-586.)

Mitchell, C.E. and A.G. Power. 2003. Release of invasive plants from
fungal and viral pathogens. Nature 421: 625-627.

The authors examined records of infection by viruses, rusts, smuts and
powdery mildews for 473 plant species native to Europe that have become
established in North America. They found 84% fewer fungi and 24% fewer
virus species infect the plants in their non-native range than in their
native range supporting the Enemy Release Hypothesis (ERH). In addition,
49% of the fungal and viral pathogens reported on these plants in North
America are native to North America, demonstrating that they have picked
up some new enemies. The authors also found that the subset of the 473
plant species which have been widely reported as agricultural or natural
area pests in North America were more completely released from viral and
fungal pathogens. In addition, they found that of the subset of plant
species listed as noxious by one or more North American states or
provinces, those that were completely without fungal and viral pathogens
were more widely regarded as noxious (i.e., they were on more lists).

Torchin, M.E., K.D. Lafferty, A.P. Dobson, V.J. McKenzie and A.M. Kuris.
2003. Introduced species and their missing parasites. Nature 421:628-630.

The authors compared the parasites of 26 host species of molluscs,
crustacean, fishes, birds, mammals, reptiles and amphibians in their
native and introduced ranges and found that the number of parasites in the
species' native ranges was twice that found in their introduced range. In
addition, they found that the percentage of individuals parasitized in
populations within the introduced range was lower than in the native
range. The host species had an average of 16 species of parasites in their
native ranges but only seven in their introduced range, an average of
three species that traveled with them from their native range plus four
"new" parasite species native to their new range. The parasite species
that tended to be left behind were those that were found in relatively low
percentages of host individuals within the native range.

***Recent scientific articles on Phragmites:

Kristin Saltonstall has published two more articles which provide further
information about and additional evidence supporting her 2002 paper on
analyses of Phragmites chloroplast DNA. The 2002 paper is summarized in
our listserve digest #107:
and it indicated that a non-native genotype had been introduced to North
America 100 years or more ago and that it has spread aggressively in
recent decades, particularly in the northeastern US, where it appears to
have displaced native genotypes.

Saltonstall, K. 2003. Genetic variation among North American populations
of Phragmites australis: implications for management. Estuaries 26 (2B):

A concise description of the research and results presented in her 2002
paper plus a short discussion of the implications for conservation land
managers. Saltonstall's analysis of chloroplast DNA determined that
several genetically distinct types (haplotypes) of Phragmites are found in
North America today. Based on comparisons with samples taken from old
herbarium sheets, it is likely that the one haplotype that now dominates
the Atlantic coast and is found elsewhere across the continent at lower
frequencies was introduced to North America sometime in the late 1700s or
the 1800s. Saltonstall notes that since native and presumed non-native
types can now be distinguished, management actions can be targeted at
controlling the aggressive, non-native type. This distinction will be
especially helpful when trying to determine whether or not to control
small and/or newly established populations of Phragmites in conservation
areas. As always, this decision should ultimately be based on whether or
not it will help protect the species, communities and ecosystem processes
you are managing FOR (your conservation targets).

Saltonstall, K. 2003. Microsatellite variation within and among North
American lineages of Phragmites australis. Molecular Ecology 12:

Saltonstall analysed nuclear DNA microsatellites from Phragmites australis
individuals from North American and European populations and compared the
results with those she obtained from analysis of chloroplast DNA which
were reported in her 2002 paper. Chloroplast DNA is inherited maternally
but nuclear DNA includes genes from both parents so this analysis was a
more sensitive way of examining whether there has been recent
hybridization between any of the lineages. The new data confirmed her
earlier findings that there are several genetically distinct types in
North America, including one that was likely introduced over 100 years ago
and which has since come to dominate the northeastern US. It also
confirmed that the type found along the US Gulf coast (and from the Gulf
of California south to northern South America) is more closely related to
the "introduced" type than to the other native types. The new data further
demonstrated that gene flow between the different types is low and that
the invasive "introduced" type is not a hybrid.

Lynch, E.A. and K. Saltonstall. 2002. Paleoecological and genetic analyses
provide evidence for recent colonization of native Phragmites australis
populations in a Lake Superior wetland. Wetlands 22 (4): 637-646.

In this paper, Saltonstall teamed up with Elizabeth Lynch to conduct a
paleoecological and genetic analysis of Phragmites in a wetland along the
Wisconsin shore or Lake Superior where it is now abundant. Analysis of
cores from the wetland yielded no evidence of Phragmites growing in the
wetland until a few decades ago and suggesting that the increase in its
abundance observed in recent years could drive (or be driven by the same
forces responsible for) significant changes in the wetland's plant
community. However, genetic data from both chloroplast DNA and nuclear DNA
microsatellites indicate that it is variety native to North America and
common in the midwest. The landscape surrounding the wetland has undergone
significant human-induced changes (e.g. widespread forest clear-cutting)
and long term environmental changes (e.g. significant changes water level
tied to changes in the level of Lake Superior) and the results of this
research suggest that these factors may have fostered the establishment
and rapid expansion of native Phragmites populations.

***And still more on Phragmites!

The Estuarine Research Federation's journal, Estuaries, recently dedicated
an entire issue (Vol. 26 No. 2B, April 2003) with papers based on
presentations given at a January 2002 workshop titled "Phragmites
australis: a sheep in wolf's clothing?" It includes one of the
Saltonstall papers summarized above plus many papers on the impacts (or
lack of impacts) of Phragmites on other species and ecosystem processes.
You can see a list of all the titles in this issue on the internet at:

Among those that I found particularly interesting were:

Ravit, B., J.G. Ehrenfeld and M.M. Haggblom. 2003. A comparison of
sediment microbial communities associated with Phragmites australis in two
brackish wetlands of New Jersey. Estuaries 26 (2B): 465-474.

Rooth, J.E. J. C. Stevenson and J.C. Cornwell. 2003. Increased sediment
accretion rates following invasion by Phragmites australis: the role of
litter. Estuaries 26 (2B): 475-483.

Raichel, D.L., K.W. Able and J.M. Hartman. 2003. The influence of
Phragmites (common reed) on the distribution, abundance, and potential
prey of a resident marsh fish in the Hackensack Meadowlands, New Jersey.
Estuaries 26 (2B): 511-521.

Jivoff, P.R. and K.W. Able. 2003. Blue crab, Callinectes sapidus, response
to the invasive common reed, Phragmites australis,: abundance, size, sex
ratio and molting frequency. Estuaries 26 (2B): 587-595.

***Research on effects of prescribed fire on the invasive annual, yellow

Kyser, G.B. and J.M. DiTomaso. 2002. Instability in a grassland community
after the control of yellow starthistle (Centaurea solstitialis) with
prescribed burning. Weed Science 50(5): 648-657

The authors treated a northern California grassland dominated by the
invasive weed yellow starthistle (YST) with prescribed fire for three
consecutive years and then tracked the abundance of the YST and other
plants there and in an unburned control site for four more years in order
to determine if the effects of the burning lasted or were transient.
Immediately following the third year of prescribed fire YST abundance had
decreased significantly (seedbank, seedling density and mature vegetative
cover were reduced by 99, 99 and 91% respectively) while native perennial
grasses and forbs, particularly legumes, had increased relative to
pre-burn treatment levels. However, the authors found that these effects
were relatively transient and YST abundance was rapidly increasing towards
pre-treatment levels while native species abundance was decreasing towards
those levels by the third year after the burns. In fact cover of native
forbs plunged well below pre-treatment values by the third and fourth year
after the burns. However, although YST seedbank and seedling abundance
approached pre-treatment values by the end of the study, cover of adult
YST never increased above 40% of the pre-treatment values. This study
indicates that three consecutive burns did not establish a stable new
community dominated by desirable native species and with low YST abundance
as had been hoped. However, it leaves open the possibility that periodic
(e.g. every 3-10 years) re-treatment with fire might result in acceptably
high native species abundances and low YST abundance at this grassland,
and perhaps in other similar northern California grasslands.

Updated September 2003
©The Nature Conservancy, 2003