by BETTER FARMING STAFF
A patch of kudzu, an invasive species of weed normally found in the southern United States, may have been established on the edge of a Lake Erie shoreline farm for 10 years or more, says provincial field crops pathologist Albert Tenuta. That’s not necessarily a bad thing, says provincial weed management program lead Mike Cowbrough.
Kudzu is a concern because it spreads quickly. “We hear about a foot (of growth) a day,” in the southern United States, says Tenuta. Because it stays green in the winter, it is also a host for yield-ruining soybean rust, which is Tenuta’s concern. Soybean rust was found for the first time in North America in 2004 and was found in fields in southwestern Ontario in 2007.
Tenuta says the Essex County patch, the first reported in Ontario, is on a south-facing slope on the shoreline between Leamington and Kingsville. Weeds have spread about 10 metres into a soybean field. Tenuta visited the patch on Monday with University of Toronto scientist Rowan Sage and graduate student Heather Coiner, who is studying how climate change affects invasive species.
Based on growth patterns, Tenuta and the University of Toronto scientists believe this patch of kudzu has been in this location for at least 10 years.
“There are a lot of things we don’t know about kudzu,” Tenuta says. Perhaps cold evening temperatures slow its growth.
Kudzu likes open areas and hasn’t spread into a stand of hardwood trees nearby.
Agricultural land managed on an annual basis is usually not an issue, Tenuta says.
Land left alone is the biggest problem.
Our normal winter would defoliate kudzu, Tenuta says. Soybean rust needs foliage to survive a winter.
Cowbrough says there are lots of questions to be answered. “Has it spread? If it hasn’t spread; why?”
If it has been in Ontario for some time “you would have thought it would have spread to other sites by now,” Cowbrough says.
The weed spreads rapidly in the United States but that doesn’t mean it will grow that quickly in Ontario. Kudzu spreads by rhizomes, like quackgrass.
“If the pest had established itself this year I would be a lot more concerned about expansion,” Cowbrough says.
The patch was found by a forestry consultant in an area where there is normally no access. This year the lake levels are low, Cowbrough says.
Tenuta points out that kudzu is a forage crop in China. In North America, its presence is “all doom and gloom.” The Essex patch is likely providing a service by preventing erosion, he says.
Cowbrough says if readers think they have seen kudzu, they can take a photo and
submit it for identification. BF
Comments
Kudzu was the darling on the conservation/erosion prevention folks in the southern states in the 40', 50' & 60's until it was shown how invasive it is. Now they look to other ground cover protection. It may be years or even a decade but as our climate becomes more accommodating it will become an invasive weed as in the United States. OMAFRA and DOE have two choices: destroy it now or effectively quarantine the site to monitor and study the progress of the invasion and understand its adaption to our climatic conditions.
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