By Brian Hefty
This summer or this fall, you may need a burndown application (or two) after harvest. What is happening with herbicide pricing, and what are the best burndown options for 2017?
First of all, Roundup has been in tight supply lately. The farmgate price around our area is up more than 25% since last fall, as well, so buying Roundup now, while still cheap per acre, isn’t super-exciting. This is just my guess, but I’ll bet you’ll see Roundup down at least a couple bucks come September 1. In other words, if you can get by on your current inventory until then, you will probably be money ahead.
Even though there are many Roundup-resistant weeds, I still like Roundup in the burndown. It’s inexpensive. It’s still good on most weed species. You can plant any crop after a Roundup application, and it’s very safe to humans and the environment (as always, though, follow the label and wear personal protective equipment). About the only big issues I see with Roundup use during summer/fall burndown are the rate and the timing. In the summer, weeds are often big with thick leaf cuticles. In other words, you need a high rate of Roundup. In the fall, applications need to be made at least a week BEFORE the first hard frost. After the frost, the effectiveness of Roundup goes way down.
For years, farmers wanted 2,4-D to throw in with Roundup, because 2,4-D was “cheap”. Now, when I compare dicamba, Roundup, and 2,4-D, the 2,4-D is the most expensive thing on the list! In my book, dicamba is a better herbicide than 2,4-D, so I will typically tell a farmer to use a generic dicamba at 1 pint per acre for burndown. Yes, you can get by in some situations with a half pint and save $2 to $3, but the weeds had better be small. On the flip side, if you are going out this fall on marestail or dandelions, I prefer 1 quart per acre. I know that’s a big rate, but trust me, if you want to wipe out your marestail population, 1 quart of generic Banvel will do the job IF you spray on a day this fall when the marestail is actively growing and the temperature is over 70 degrees. The dicamba price has been on a sharp decline the last 2 years, and that will continue this fall. Again, if you can hold out until September 1, I would expect a much lower price on dicamba.
Gramoxone, or one of the many generic versions, has also gotten a lot less expensive this year. The big difference between Gramoxone and Roundup is that Gramoxone doesn’t kill roots. If you have perennial weeds, Roundup is far superior. One other tip when it comes to perennials is to spray Roundup by itself. Don’t have dicamba in there, for example, as that will shut the plant down before the Roundup can get into the root system. With annuals it doesn’t matter, but with perennials, use Roundup only. Back to the Gramoxone, it works best with crop oil or methylated seed oil AND either dicamba or 2,4-D. I like Gramoxone because it kills weeds faster than any other herbicide. Since a quart of the 3# generic is now only $4 per acre, Gramoxone is getting on a lot more acres in place of Roundup.
If you want long-term residual, you’ve got the cheap option, Valor, or the more expensive choice, Sharpen. Sharpen has a little better burndown activity, but Valor will likely last longer in the soil. Both are PPO products with relatively short rotational restrictions to a wide variety of crops, and both are good tankmix partners for almost anything on the list above. A big rate of 3 ounces of Valor is under $10 per acre. You can use 2 to 3 ounces of Sharpen for $10 to $15 per acre.
There are literally dozens of other active ingredients that may be recommended to you for your burndown application this year. There are so many different product names and premixes, it’s dizzying even for me, and I deal with this stuff every day. My best advice is make sure you get a herbicide combination that will do a great job controlling your weeds without hurting your next crop. I usually stick to the products I’ve listed above to keep it simple, but there are occasionally situations where I might use something else. For the most part, though, I’m pretty comfortable with the herbicide choices I’ve listed.