This is in a food plot that is somewhat moist in central Minnesota. I’ve sprayed the plot with gly. Most everything else is dead but this does not. I went back and spot sprayed it, same results. What weed is this and how do you kill it?
That is field horsetail not marestail. Gly wont kill it. Ag phd had it has their weed of the week years ago. Better drainage was one way to control it. I also believe they mentioned using gramoxone for some control also. Hi-yield has a product that might control it but I never used it. I have it in a few of my plots also and it seems like it spreads just a little bit every year. Tillage can help it spread.
The picture is not from the food plot but from a different place that I saw it. I have not tried broadleaf spray. I did add some Dawn dish soap to my 16 gallon tank sprayer. I’m not sure how much to use, I think I used 4-5 oz of Dawn. I disc it up last weekend if I find more I’ll bring it to the local feed mill to see what they suggest. JMB, thanks for the link. I’ll check into it.
I'm with jmb in that it doesn't look like marestail to me. If it's horsetail you might consider soil pH. Horsetail thrives on acidic soil but will disappear if you get the pH up. Have you done soil tests? Do you know your pH? If not it's not a big deal, the plants are telling you what your soil needs.
I don't know your experience level so I'll kind of explain in simple terms. If you already know this stuff then ignore the rest of this!... Acidic soil (pH less than 7) inhibits fertilizer uptake in plants. Your plots will not do as well if your pH is low. "Lime" will bring your pH up closer to 7. Lime can be purchased in bulk and delivered, or it can be bought by the bag. Either way it's cheap. It takes a lot of lime to change much and it works slow so it's a long term project, but it might help reduce weeds with less sprays and give you healthier plots that are preferred by deer. Most of the time you need ton's per acre to get the change you need but it's easy and can be done a little at a time. In the mean time the spray that jmb recommended might help control it.
I deal with a lot of weeds that have tough exteriors and my Cenex agent had me switch to an oil based surfactant. It's pretty cheap and gets the herbicide to the weed much better. Almost essential when dealing with whitetop.
whatever it is I grow it well! As mentioned above I have acidic poorly drained soil in places and that is where it thrives. I have had limited success killing it with round up or 2-4-d, I haven't worried about it too much since I don't feel it is all that harmful to my crops. It seems pretty easy to outcompete it. I am definitely adding a surfactant next year, I have added dish soap in the past.
Here's some more info: http://wric.ucdavis.edu/information/natural%20areas/wr_E/Equisetum.pdf
I would be super careful if you decide to use paraquat. It can be deadly if you breath the fumes, drink it, or get it on your skin! Paraquat is a contact herbicide and will likely injure any desirable plants that it comes in contact with while spraying.