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Global Invasive Species Team listserve digest #063
Fri, 2 Jun 2000 16:15:35 -0700 (PDT)


1. Krenite herbicide (Indiana)
2. Hairy willow herb (Wisconsin)
3. Giant hogweed or water hemlock (New York)
4. Burning bush honeysuckle (Wisconsin)
5. Reviews on articles (Nationwide)


1. Krenite herbicide (Indiana)
From: Ellen Jacquart (ejacquart(at)tnc.org)

Has anyone out there used "Krenite" herbicide? We are thinking about
using it on multi-flora rose (Rosa multiflora) and are interested in
hearing from anyone who's had experience with the stuff (especially in
terms of non-target damage).

2. Hairy willow herb (Wisconsin)
From: Steve Richter (srichter(at)tnc.org)

Should we be concerned with Hairy Willow Herb? No, you won't find this in
the bulk food section of your local organic food co-op. It is a alien
plant (Epilobium hirsutum) that grows in a wet prairie swale at a
Wisconsin TNC site. I do not see it anywhere else in the state. It has
been present for at least five years, and the population hasn't increased
dramatically. It seems to compete well with cattail. Does anyone have
any experience with this species?


3. Giant hogweed or water hemlock (New York)
From: Chris Winters (cwinters(at)tnc.org)

Do you know of any person or program working on control of giant hogweed
(Heracleum mantegazzianum) or water hemlock (Cicuta spp.)?


4. Burning bush honeysuckle (Wisconsin)
From: Nancy Braker (nbraker(at)tnc.org)

We have a location (Lulu Lake) where we had a significant understory of
bush honeysuckle (Lonicera), buckthorn (Rhamnus and Frangula) and other
shrubs (natives included). We have burned a small section of this site
every year for 10 years, to see if we could reduce the shrub layer. We
have significantly reduced all shrubs, and have virtually eliminated the

Drawbacks to this approach are the other potential impacts on the
vegetation such as reducing native spring wild flowers that don't get a
change to set seed, or eliminating fire intolerant, but native species.
You really need to burn frequently or you don't make any headway on the

Because this site has a good oak overstory, a thick layer of oak leaves
was available for fuel, our fires were hot enough to get the shrub kill

We'd be happy to talk to Tim some more about this if he wants to call
myself or Steve Richter.


5. Reviews on articles (Nationwide)
From: John Randall (jarandall(at)ucdavis.edu)

**Articles on Impacts of Invasive Plants

Lippincott, C.L. 2000. Effects of Imperata cylindrica (L.) Beauv.
(cogongrass) invasion on fire regime in Florida Sandhill (USA), Natural
Areas Journal, 20:140-149.

Carol Lippincott examined attributes of fine-fuels and fire behavior in
sandhill areas invaded by the non-native cogongrass (Imperata cylindrica)
and compared them with adjacent uninvaded sites. Invaded sites had
significantly greater fine-fuel loads, horizontal continuity, and vertical
distribution. Fires in invaded sites were more horizontally continuous and
had higher maximum temperatures at greater heights. Rate of fire spread
and calculated fire intensity were similar in invaded and uninvaded sites,
however. Fire-induced mortality of juvenile longleaf pine (Pinus
palustris; the dominant tree in these systems) was greater in invaded
sites. After fires, fine fuels accumulated more rapidly in invaded sites.
Lippincott notes that cogongrass is distinctly different from native
grasses. She suggests that these differences effect fire behavior and
fuel accumulation in way that may result in higher mortality of native
herbaceous and woody plants leading to a shift in species composition from
species rich pine-savanna to grassland dominated by cogongrass just as has
already occurred in some previously forested systems in southeast Asia.

Schulz, K. and Thelen, C. 2000. Impact and control of Vinca minor L. in
an Illinois Forest preserve (USA), Natural Areas Journal, 20:189-196.

Species richness, evenness and combined diversity were not significantly
different between a Vinca minor infested plot and an uninfested reference
plot at a natural area in southwestern Illinois. A combined cutting and
glyphosate application treatment reduced Vinca minor cover in the infested
plot by about 50% and increased cover of non-vegetated surface and species
richness. Species composition in the treated portion of the infested plot
more closely resembled that in the uninfested reference plot than did the
untreated portion of the infested plot. Note that this was a case study
from just one site, that treatments were not replicated and that the
researchers have no data describing the vegetation before Vinca invaded.

**Articles on Impacts of Control

Haney, R.L., Senseman, S.A., Hons, F.M. and Zuberer, D.A. 2000. Effect of
glyphosate on soil microbial activity and biomass, Weed Science, 48:89-93.

This study found that glyphosate added to a cropland soil significantly
stimulated soil microbial activity as measured by C and N mineralization
but did not affect soil microbial biomass. Cumulative C mineralization and
mineralization rate increased as the amount of glyphosate added increased
and the relationship indicated that glyphosate was the direct cause of the
enhanced microbial activity. These trends continued for 38 to 56 days
depending on the amount of glyphosate added. Glyphosate appeared to be
directly and rapidly degraded by soil microbes, even at high application
rates. It should be noted that the soil used was taken from cropland that
was unfertilized but which had presumably been treated with herbicide
repeatedly in the past.

Heard, T.A. and Winterton, S.L. 2000, Interaction between nutrient status
and weevil herbivory in the biological control of water hyacinth, Journal
of Applied Ecology, 37:117-127.

Water hyacinth (Eichhornia crassipes) growth and the impacts of two weevil
species on that growth were measured under high and low nutrient
concentrations. Results confirmed that biocontrol of water hyacinth is
more likely to be effective in low nutrient waters where water hyacinth
grows more slowly. In high nutrient waters, one of the two biocontrol
species, Neochetina bruchi, is significantly more effective against water
hyacinth than another, closely related biocontrol agent, N. eichorniae.

Luken, J.O. and Shea, M. 2000. Repeated prescribed burning at Dinsmore
Woods State Nature Preserve (Kentucky, USA): responses of the understory
community, Natural Areas Journal, 20:150-158.

Conducting autumn prescribed burns for two or three consecutive years did
not significantly effect garlic mustard (Alliaria petiolata) abundance or
relative importance in upland or lowland sites. This corroborates other
research demonstrating that dormant season (autumn) burning does not
control garlic mustard.

Updated June 2000
©The Nature Conservancy, 2000