This is the sugar beet report, bringing you the latest information from NDSU throughout the sugar beet growing season. With most sugar beet rows closed, wheat escapes are the next challenge. Tom Peters, NDSU and University of Minnesota Extension sugar beet agronomist, has an electric solution. Tom, I can see waterhemp towering over some of the closed sugar beet fields. What weed control sprays are available?

At this point of the season, those three or four or five foot weeds that are in fields, we can't control those anymore with herbicides. So I want to make sure our audience knows that we're going to have to find creative ways to control those weeds because we're past the point of making herbicide applications.

What are the best control options then?

Well, I can think of two. The first one is to go out and pull them. The normal response is, what's your second option then? What we'll talk about today is a machine called the Weed Zapper using electricity to kill weeds.

How does it work?

This is an ingenious machine, Bruce. It's a machine where you're essentially pulling a generator behind a tractor. So the electricity that you produce is transferred to a bar in the front of the machine. And when the bar comes in contact with weeds that are taller than our crop canopy, the electricity is transferred into the weeds itself. The wet conditions that we have right now are excellent conditions for the transfer of electricity in these weeds. And waterhemp is a plant with a lot of stem, so electricity does a good job of transferring through the bar and into the weed. And the way it works is the heat energy that is produced essentially blows up the water in cells. The metaphor that I like to use in meetings, it's in Star Wars, where the Death Star, they bomb it and it starts this explosion. And one explosion leads to another and another and another. And that's kind of the way electricity works. There's a series of explosions that occur as the cells heat up and the water boils and ruptures the cells. And you see this very, very rapid wilting phenotype when you run the machine through the plant. Now the ability to kill a weed is dependent on the flow of electricity, how much electricity moves into the lower part of the plant.

What else do we need to know?

Well, couple of things. People often ask about making repeat applications or maybe going out a second time. In our research we found that going down and then immediately coming back isn't best. If you want to make a repeat application, it's best to wait five or seven days. And the reason for that is sometimes waterhemp is at different stages. So by waiting, you'll have that flush of waterhemp that has emerged above the canopy since the first application. The second thing is sometimes we get regrowth and this isn't a perfect solution, especially on weeds like waterhemp with a lot of growing points, we'll see regrowth that comes from the bottom of the plant.

Tom, can we use the Weeds app around other weeds?

It's interesting. It works the best on waterhemp. I mentioned it's because of the stem, the biology of waterhemp and the long stem, the prominent stem. On plants that are highly branched like kochia or common ragweed, the weed zapper doesn't work as well because of all the branching. Also on grasses, we don't have as good of results as we have with waterhemp. Now ultimately what we're doing this time of year is we are killing some plants, but we're also reducing the viability of the seed that the waterhemp is producing. So for that reason alone, I think using the weed zapper makes a lot of good sense for farmers.

Thanks, Tom. Our guest has been Tom Peters, NDSU and University of Minnesota extension sugar beet agronomist. This is the sugar beet report, bringing you the latest information from NDSU throughout the sugar beet growing season.