In general, horseweed (marestail) populations are much lighter than usual. The only reason I can see for this is the very dry fall curtailed germination. This was not the case for henbit which is much more prevalent and more of a problem than usual. The weather this March gave us very few days to get a lot of spraying done. As a result, there are still a lot of burndown applications to be applied. Also, as the rivers finally fall there are always islands that do not go underwater but are not accessible to spray timely. Below are the results of one of our burndown trials conducted at Jackson, TN. Every spring is a little different on how various tankmix combinations provide weed control. These data should provide some insight as you tailor your later burndown applications.
The data below was rated 12 days after application (DAA). It shows that the newer horseweed burndown options Verdict and Sharpen are working quickly on horseweed. The Clarity and 2,4-D are working more slowly. My experience would say that the Clarity + glyphosate and Clarity + glyphosate + Valor combination will provide 90% plus horseweed control by 21 DAA. Henbit is a different story. Pretty much the control one sees by 12 DAA would be all you get.
Rating Taking 12 Days After Application
|
Tankmixture |
Horseweed |
Henbit |
|
Verdict* 5 oz + RPM** 22 oz |
99 a | 63 b |
|
Verdict 5 oz + Valor 2 oz + RPM 22 oz |
99 a |
76 a |
|
Authority MTZ 10 oz + RPM 22 oz |
34 d |
45 c |
|
Clarity 8 oz + RPM 22 oz |
70 b |
43 c |
|
Clarity 8 oz + RPM 22 oz + Valor 2 oz |
69 b |
72 a |
|
Sharpen* 1 oz + RPM 22 oz |
99 a |
65 ab |
|
Sharpen 1 oz + Valor 2 oz + RPM 22 oz |
99 a |
76 a |
|
2,4-D 24 oz |
61c |
58 b |
| Clarity 8 oz | 54 c |
30 d |
* All Verdict and Sharpen applications were applied with 1% MSO + 1% AMS
**Roundup PowerMax
we are using rpm. 2-4 d, rifle, and atrazine on our corn ground, and it is looking to be doing a great jod.espsecially for this think flush of henbit we have. as far as burn down for soybeans, we’re not having an early beans, just wheat beans. so hopefully this year we will has a little less pressure from resistant pigweed!
Tyler
That is a good burndown recommendation for Corn. It has taken a “burner” like atrazine, Gramoxone Inteon or Valor to get henbit to dry down. The pgrs alone this year are not working well on henbit.
Larry