Controlling Marestail In Double-crop Soybeans

Jun 26, 2013

This is essentially a repeat of an article that ran last year at this time. Little has changed since then with the exception that Liberty has been even harder to procure this year, so using a glyphosate+Sharpen burndown may be more realistic.

A weed free start is the most critical aspect of a weed management program for double-crop soybeans. This can be challenging to achieve where glyphosate-resistant marestail are present after wheat harvest. Problems with marestail include the following: 1) most populations are now glyphosate-resistant and many of these are also ALS-resistant; 2) it’s usually not possible to use 2,4-D ester and wait 7 days until double-crop soybean planting; and 3) marestail that were tall enough to be cut off by harvesting equipment will be even more difficult to control. Our research indicates that there are no herbicide treatments that consistently control glyphosate-resistant marestail populations that have regrown following mechanical disturbance or prior herbicide treatment. Certainly one of the best options is to plant LibertyLink soybeans, which allows for a POST application of Liberty to help control plants that survive a preplant burndown. The following are the most effective burndown options for control of mare
stail prior to double-crop soybean emergence:

Liberty (32 to 36 oz) + Sharpen (1 oz) + MSO + AMS (can also add metribuzin)

Liberty (32 to 36 oz) + metribuzin (4 to 8 oz of 75DF) + AMS

Glyphosate (1.5 lb ae/A) + Sharpen (1 oz) + MSO + AMS

We suggest using a spray volume of 20 gpa for any of these treatments, and avoiding nozzles that produce large droplets. Results with a combination of glyphosate and 2,4-D may be more variable then the treatments listed.

With regard to the control of weeds that can emerge after double-crop soybean planting, and the entire weed control system, the following approaches can be considered.

1. Plant any type of soybean, and include a residual herbicide with the burndown treatment so that POST herbicides are not needed. A good strategy in Roundup Ready or nonGMO soybeans even where POST treatment is needed, since POST marestail control might be impossible in these systems. Residual herbicides used at this time of the year should be restricted to those that have little or no carryover risk – such as metribuzin, Valor, or low rates of chlorimuron or cloransulam products.

2. Plant a LibertyLink soybean, and apply Liberty POST as needed. Probably the best option for control of later-emerging marestail or plants that regrow after the burndown, assuming that there is any Liberty available.

3. Plant a Roundup Ready soybean and apply glyphosate POST. Should work for most weeds, but not a good choice if the POST application needs to control marestail.

4. Plant a nonGMO soybean and apply conventional POST herbicides (Flexstar, Fusion, Select, etc) as needed. This system has the most potential for soybean injury, but seed may be cheaper than the other systems. Not a good choice if the POST application needs to control marestail.

Source : osu.edu

Video: Spring 2026 weather outlook for Wisconsin; What an early-arriving El Niño could mean

Northeast Wisconsin is a small corner of the world, but our weather is still affected by what happens across the globe.

That includes in the equatorial Pacific, where changes between El Niño and La Niña play a role in the weather here -- and boy, have there been some abrupt changes as of late.

El Niño and La Niña are the two phases of what is collectively known as the El Niño Southern Oscillation, or ENSO for short. These are the swings back and forth from unusually warm to unusually cold sea surface temperatures in the Pacific Ocean along the equator.

Since this past September, we have been in a weak La Niña, which means water temperatures near the Eastern Pacific equator have been cooler than usual. That's where we're at right now.

Even last fall, the long-term outlook suggested a return to neutral conditions by spring and potentially El Niño conditions by summer.

But there are some signs this may be happening faster than usual, which could accelerate the onset of El Niño.

Over the last few weeks, unusually strong bursts of westerly winds farther west in the Pacific -- where sea surface temperatures are warmer than average -- have been observed. There is a chance that this could accelerate the warming of those eastern Pacific waters and potentially push us into El Niño sooner than usual.

If we do enter El Nino by spring -- which we'll define as the period of March, April and May -- there are some long-term correlations with our weather here in Northeast Wisconsin.

Looking at a map of anomalously warm weather, most of the upper Great Lakes doesn't show a strong correlation, but in general, the northern tiers of the United States do tend to lean to that direction.

The stronger correlation is with precipitation. El Niño conditions in spring have historically come with a higher risk of very dry weather over that time frame, so this will definitely be a transition we'll have to watch closely as we move out of winter.