Why Does Poison Ivy Grow?
Wednesday, July 27, 2016
That is the questions a team of researchers at Virginia Tech are trying to answer through a new project.
John Jelesko, associate professor of plant pathology, physiology, and weed science in the College of Agriculture and Life Sciences, David Haak, an assistant professor in the same department, and Lynn Resler, an associate professor in the College of Natural Resources and Environment, at Virginia Tech are now using samples of poison ivy from different parts of the Appalachian Trail — including a 100-kilometer transect from near Blacksburg to Peaks of Otter — as a laboratory to determine why and how the poison ivy plant grows and spreads.
“In many ways this plant is the familiar stranger,” he said, “We’re all told ‘leaves of three, let it be,’ and that’s all very sensible, but beyond that there is remarkably little specific scientific knowledge about poison ivy” said Jelesko.
In order to collect geolocational data of the plant the team used a smartphone app that enables users to tag where they find poison ivy. Jelesko, a Fralin Life Science Institute-affiliated faculty member, and his team stopped at every “white blaze” marker along a 60-mile segment of the Appalachian Trail to catalogue and tag samples. The project was funded by a College of Agriculture and Life Sciences Proposal Development grant.
Through a couple of years of investigation, Jelesko has learned a few things about the plant like a unique way to kill it and how it reproduces.
Jelesko has figured out there’s a fungus that naturally grows on the plant’s seeds. He hypothesizes that the fungus appears on the seeds to prevent seedling competition with mother poison ivy plants. The only way the fungus will disappear in the wild is when it passes through the digestive tract of a bird.
The fungus can then be used to kill poison ivy and doesn’t appear to harm other organisms, other than an invasive insect found in New England for which it was first practically applied.
Birds and mammals other than humans don’t get rashes from poison ivy when they come into contact with urushiol, Jelesko said. Deer will eat the plant “like crazy,” he said. For an unknown reason, the chemical in poison ivy afflicts only people.
Jelesko hopes to eventually hike the entire Appalachian Trail and extensively catalogue the poison ivy samples he finds along the way, as well as enlist the help of citizen scientists in geotagging poison ivy populations.