Each year it seems a different weed becomes the mystery weed to identify, says Rich Zollinger, North Dakota State University Extension weed specialist.

"To this point, waterpod seems to have the crown," he says.

Waterpod is an annual broadleaf plant in the Waterleaf family. There are no other common weeds in this family that infests cropland in the Northern Plains.

Waterpod is a new weed not usually seen in the Northern Plains. Photo: Rich Zollinger

"My experience with waterpod has been intermittent – it has been more of a "nuisance" weed and it shows here and there and rarely in high densities," Zollinger says. "It does not seem to be tolerant to many POST herbicides.  My Extension predecessors did not leave a file on waterpod and I did not find much additional information about it on the web either. I suspect the cool and moist conditions must be conducive to emergence and growth, and glyphosate and most POST herbicides will control it."

Refer to photo for help in identification.

Ag PhD featured waterpod as its "Weed of the Week" in 2009, after a wet fall and spring. The TV shows' co-hosts, Brian and Darren Hefty, of Hefty Seed Company, Baltic, S.D., also noted waterpod was easy to control in corn and soybeans with glyphosate and several POST herbicides. It really didn't compete well with winter wheat, they said. Remember to spray untreated planted of the field when you are spraying the crop to make sure you get it under control, they suggested.

While waterpod is considered a nuisance weed in the Dakotas, in New Jersey and Pennsylvania it's a protected species. In New Jersey, waterpod -- also known as Aunt Lucy -- it is on the endangered list. In Pennsylvania it is on the states threatened list.