Adjuvant choices that make early burndown strategies more successful

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Early Season Adjuvant Strategies – Burndown

Steve Doench, Head of Sustainable Agronomy
Written by Steve Doench, Head of Sustainable Agronomy

Spray adjuvants are a helpful tool for increasing the effectiveness of herbicides. At this time of the year, the early season burndown,  there is no concern about the safety and efficacy of post-emergence herbicide applications on increasingly complex weed control systems. It is about setting up efficient weed control strategies that can last through the season in which the right adjuvant plays a crucial role.

As the snow melts in the north and flowers start to bloom in the south, it is once again time to get fields in the best shape possible so that season-long weed control can be successful. The pre-season preparation will set up each acre for productive crop growth and the best yield without restrictive competition from weeds.

Learn how adjuvants can help with the early season tasks of burndown.

Early Season Burndown Strategies

Where planned and conditions allow, burndown herbicide applications help the season start with as much of a clean slate as possible so that the herbicide program gets off and running well before the planter hits the field.

Burndown fundamentals:

    • Start as early in the season as possible
    • Consider weather forecast
    • Use herbicides that have residual activity for prolonged control
    • Know what is the best application time during the day
    • Select the right adjuvant
Weed burndown strategy benefit from the right adjuvant choices

Seasonal & Weather Implications

Starting as early as field conditions allow and winter annuals are still small and easy to kill makes weed control easier. Taking the weather forecast into account and timing applications accordingly to ensure that weeds are actively growing and react to the herbicide is essential. During less cloudy and warmer temperatures, highs in the 50s or above and lows above freezing are ideal weather conditions for applying herbicides.

Optimize Control

Consider using multiple modes of action when possible. Traditional burndown herbicide programs utilize non-selective herbicides that provide little or no residual weed control in the soil. These herbicides only clear what overwintered or emerged early in the fields. Burndown herbicide applications that create some form of residual soil activity and are safe for the upcoming crop provide a great head start on keeping weeds under control from the start of the season. No-tillage systems in particular rely on effective burndown herbicide applications to prevent uncontrollable weeds in the field after planting.

Adjuvant choices that make early burndown strategies more successful

Time of Day

Not every herbicide works well at each time of the day, so it is essential to know what the best time of the day is to apply. Some herbicides, like paraquat, benefit from being sprayed early or late in the day to maximize efficacy. At the same time, glufosinate performs best during the middle of the day when target plants are most active.

Select the Right Adjuvant

Not all active ingredients are created equally, and it is crucial to select the right adjuvant that works with your active ingredient. The use of spray adjuvants helps maximize the success of burndown herbicide applications by ensuring that the active ingredient reaches the targeted weeds. Adjuvants affect leaf coverage (deposition) and leaf penetration. Active ingredients list the type of adjuvants required on their labels. Burndown applications containing glyphosate typically call for the use of ammonium sulfate (AMS) and a surfactant.  In hard water regions, the use of AMS and a water conditioner helps to prevent antagonism of additional tank-mix partners. If tank ingredients don’t play well together, they reduce the efficacy of the application. Broadleaf-focused herbicides benefit from using oil-based activator adjuvants to penetrate leaf surfaces and get into the plant.c

When looking at herbicides with residual soil activity as part of a burndown application and are compatible with the crop to be planted, the addition of a soil deposition aid is beneficial to allow for better soil adsorption, decreased run-off, and less leaching.  These adjuvants also help increase soil contact and slow evaporation to enable effective and prolonged residual activity. 

As the season approaches, ensure the burndown herbicide applications are as successful as possible so this season’s crops will have a great start. 2021 appears to have an excellent commodity price environment that can maximize profits which is a welcome difference after these past challenging years.

Exacto provides customers with a broad range of formulations that help make early-season applications successful.

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