Department of Ag and U of M team up to help Winona County combat invasive Oriental bittersweet


New drone technology could help!

With grants from the Minnesota Department of Agriculture (MDA), Winona County has been providing labor, education and herbicide as assistance to landowners plagued with an invasive vine called Oriental bittersweet. Not to be confused with the mild-mannered American bittersweet, this non-native thug has turned out to be a serious invader! The vines spread into tree canopies and smother and kill mature trees, affecting hunting, timber value and wildlife. It is prevalent in the hillside forests surrounding the city of Winona, with the worst infestations found in Homer and Wilson townships. The University of Minnesota-Extension, MDA, Minnesota Department of Transportation, the Conservation Corps, Soil and Water Conservation Districts, and County Planning & Environmental Services have been working cooperatively to tackle the issue with landowners.

Last year’s fieldwork revealed the problem was older and more severe than was expected. Researchers and volunteers are hoping to call a halt to the progress of this python-like vine by turning to the skies in Homer Township to map the extent of the infestation using drones. This assessment will jump start crews next year because finding the vines on foot is labor-intensive and can be challenging on steep terrain. A drone test flight (with property owner permission) took place on December 18, 2018.

“With Winona’s extensive infestation, we want to target fruit-producing female vines first, to reduce spread. However, it’s been hit-and-miss for us to find these big fruit producers given the challenging bluff terrain. Surveying bittersweet from the air may provide us with the information we need to determine which areas to prioritize,” said Monika Chandler, MDA invasive species specialist.

Angela Gupta, UM-Extension educator in forestry, added, “Winter may be the perfect time to survey for [Oriental] bittersweet. With the leaf cover gone, the white snow provides an excellent contrast to the bright red fruit and messy mass of vines at the tops of trees that is characteristic of dense bittersweet infestations. This might give us the leg up we need to contain and control this invasive vine.”

The recent drone research project is a joint venture between the MDA and the U of M, and is funded through a grant by the Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizens Commission on Minnesota Resources.

Winona County landowners who believe they have Oriental bittersweet on their property should report the suspected infestation to or call 507-457-6468.


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