Ford Baldwin

November 6, 2009

4 Min Read

Before continuing with my pigweed control articles, I have tried to think of something encouraging to say about trying to get a crop out with the weather we are having. Unfortunately I can’t think of anything other than “I care.”

I hate droughts and every time we go a couple of weeks without a rain I figure we are in for one. However, I can never remember a year where it has rained — often in large amounts — seemingly every week all season.

It has to be frustrating to finally get a crop made and either see it ruining in the field or not be able to get it harvested. As I have said in a lot of articles, it is sure a lot easier for me to sit back and give you advice on how to farm than to get out there and do it.

I have not mentioned my grower support role with Riceland Foods in several articles. Most of my telephone calls come during the growing season, for obvious reasons. However, if you just need to call someone for moral support during a frustrating harvest, I can be here for that, too.

Do not ever think you will be bothering me. While I can not change the weather, I can listen and do care.

Getting back on the pigweed topic, I mentioned last week that the key to making the LibertyLink soybean system successful for pigweed and grass control was to treat it like a LibertyLink program and not a Roundup Ready program. Getting back on the pigweed topic, I mentioned last week that the key to making the LibertyLink soybean system successful for pigweed and grass control was to treat it like a LibertyLink program and not a Roundup Ready program. While the overall LibertyLink and Roundup Ready programs can be quite similar, you can not treat Ignite like Roundup when it comes to controlling pigweeds and grasses.

I recommend the use of a residual in a LibertyLink program for a couple of reasons. First, a residual treatment when activated can take a lot of pressure off the postemergence program.

Some folks put a lot if stock in the residual treatment “buying time” for the first postemergence application. I never assume that; if it happens, it is a bonus.

If the residual treatment provides 100 percent control early, it can buy you some time. However, 50 to 80 percent control is a much more realistic expectation and those weeds that escape will often require the same postemergence application timing that would be required if the residual was not there.

What the residual should do, however, is reduce the weed population and reduce the chances of the weeds simply overpowering the postemergence treatment.

In addition, the residual treatment should reduce the level of re-infestation following the first postemergence treatment.

The second thing a residual treatment adds to LibertyLink program is a resistance management tool. For growers thinking about the future, the time to begin a resistance management program with a new herbicide mode of action is on the front end.

In hindsight, we should have been using a lot more residual herbicides and tank mix partners in our Roundup Ready programs from the start. However, when a couple of applications of Roundup alone worked so well for so long, it was hard to think about doing anything else. We are paying for that now.

New herbicide modes of action do not come along very often anymore. Therefore, being much more proactive with residuals and tank mix partners in a LibertyLink program makes good sense, even though they may not always be required.

Assuming most of the LibertyLink soybeans will be planted on Palmer pigweed acres, you won’t necessarily be as dependent upon residual herbicides in a LibertyLink program as you would be in a conventional soybean or Roundup Ready program. Instead of needing three residual herbicides, you may only need two; or instead of needing two, you may only need one.

From an overall weed control perspective, two timely applications of Ignite in a LibertyLink program will compare very favorably with two timely applications of glyphosate in a Roundup Ready program. However, when you load the LibertyLink system up with Palmer pigweed and grasses, some residual sure helps the program and it makes good sense for resistance management.

e-mail: [email protected]

About the Author(s)

Ford Baldwin

Practical Weed Consultants

Ford Baldwin served as a weed scientist with the University of Arkansas Cooperative Extension Service from 1974 to 2001. During that time he conducted extensive applied research trials in rice, soybeans, cotton and wheat, and developed weed management recommendations and educational programs for farmers. Since January 2002, Baldwin has been a partner in Practical Weed Consultants with his wife, Tomilea.

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