How to Effectively Control Weeds With MSO

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How to Effectively Control Weeds With MSO

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Brief history of Oils as adjuvants in Weed Control

Adjuvants are substances that are added to herbicides to increase their effectiveness and efficiency in weed management. Petroleum-based oils were one of the earliest adjuvants used in herbicides. These oils were well-known for their capacity to improve herbicide performance and were frequently utilized in the 1950s and 1960s. Its effectiveness was, however, constrained by several issues, such as phytotoxicity, decreased herbicide persistence, and increased volatility, which were linked to their use.

Early in the 1970s, methylated seed oil, a new kind of oil-based adjuvant, was created to address these issues (MSO). The introduction of MSO transformed the application of oil-based adjuvants in herbicides. Farmers saved money because of its enhanced performance, which increased herbicide efficacy and reduced application rates. In addition, MSO is less phytotoxic than petroleum-based oils, making it safer to use on crops without endangering them.

The role MSO-based adjuvants play in the chemical control of weeds:

Methylated seed oil (MSO) is a type of oil-based adjuvant that has become the industry standard for enhancing the efficacy of herbicides. 

Enhancing or preserving the effectiveness of herbicides is one of the key functions of MSO-based adjuvants in the chemical control of weeds. MSO can improve the absorption and transport of the herbicide within the plant, improving weed control when used in conjunction with herbicides.

Moreover, MSO-based adjuvants are well known for their capacity to lessen spray solution surface tension, which enhances the coverage and distribution of the herbicide. Controlling weeds with difficult-to-wet foliage, such as those with a thick cuticle or waxy leaves, might make this particularly crucial.

Another benefit of using MSO-based adjuvants is the cost and time savings they provide. MSO-based adjuvants can lower the amount of herbicide required to achieve the desired degree of weed control by increasing the efficacy of herbicides. As a result, farmers can lessen the impact of their activities on the environment and save money on herbicide expenditures.In addition, MSO-based adjuvants can aid in reducing the number of spray applications required, saving farmers time and labor, thanks to the enhanced coverage and distribution of herbicides they give.

Features of MSO-based oil:

  • MSO is a green and renewable substitute for petroleum-based solvents, and many farmers and applicators favor it because of its special qualities.
  • MSO is a biodegradable substance that decomposes naturally over time and is manufactured from modified vegetable oil to enhance performance. This transforms it into a more environmentally responsible and sustainable adjuvant than petroleum-based ones.
  • MSO-based oil is safer than using conventional petroleum-based adjuvants. It is a safer option for individuals handling herbicides because it has a lesser flammability and poses less risk to the applicator. In high-risk scenarios when applicator safety is essential, this is especially crucial.
  • Manufacturers and academics alike have endorsed MSO-based oil for its greater performance enhancement over conventional petroleum oil-based adjuvants. Due to the high content of fatty acid-based structure in MSO, the herbicide can penetrate the plant more deeply, increasing its effectiveness and weed control.
  • MSO-based adjuvants, in comparison to Petroleum-based adjuvants, feature a lower flammability and improved safety in the handling of MSO-based products.

General category of weeds that benefits from MSO-based adjuvants:

Methylated seed oil (MSO) based adjuvants are commonly used in the chemical control of weeds and are especially effective in the managing of Broadleaf weeds, but also have been found to be very effective in some Grass weeds such as the giant foxtail. 

Broadleaf weeds and other weeds with tough-to-wet foliage are most likely to benefit from MSO-based adjuvants. Contrarily, grass weeds have a cuticle that is thinner and more permeable, and may not always require the penetrating effects of adjuvants made from MSO. Although some severe conditions may cause some grass weeds to develop a thicker waxy leaf cuticle. To learn more about specific weeds you maybe targeting, you can visit the Weed Science Society of America (

Due to their particular growth patterns and structural makeup, broadleaf weeds are frequently more challenging to eradicate than grass weeds. They are often more resistant to herbicides because of their bigger leaves and intricate root systems. Nevertheless, MSO-based adjuvants can aid in overcoming these difficulties by enhancing the plant’s ability to absorb and transport herbicides. Higher agricultural yields and better weed control are the results.

Recommended rates for MSO-based Adjuvants:

The recommended herbicide treatment rates can change depending on the target weed species, development stage, and environmental variables when it comes to chemical weed management. Either a general per-acre suggestion or a general per-volume recommendation is typically used to convey herbicide treatment rates. Please refer to the herbicide label for detailed instructions on rates since a violation of the herbicide recommended rate can nullify any claims to ineffective product. MSO is becoming a more highly recommended adjuvant but there are also many instances where other types of Adjuvants are required.

  • General per acre recommendation for MSO-based Adjuvants:

When the targeted weed species is known to exist in a specific area, per-acre recommendations are frequently employed. In these situations, herbicide labels will normally suggest a particular dosage per acre in order to effectively manage weeds. The per acre recommendation is also generally given when the aim of the adjuvant is to treat plant surface. Depending on the type of herbicide, the species of weed, and the surrounding conditions, this advice might change. MSO are generally recommended at a rate of 1 – 2 pints per acre

  • General per volume recommendation for MSO-based Adjuvants:

On the other hand, per-volume guidelines are more frequently employed when applying herbicides with the goal of impacting the surface tension of water in the tank mixture. The amount of herbicide to be applied per unit volume of water, such as gallons or liters per acre, is the basis for these recommendations. Depending on the desired level of weed control and the surrounding conditions, the label may offer a variety of per-volume recommendations. In order to ensure efficient and secure herbicide application. MSO are generally recommended at a rate of 0.5 – 1.0 v/v% (2 – 4 quarts per 100 gallon).

Brewer Products:

Brewer Products is a well-known supplier of aquatics and agricultural adjuvants that have MSO as either a primary or secondary functional ingredient. These products are made to improve the effectiveness of fungicides, insecticides, and herbicides while increasing spray coverage.

  • Brewer products with MSO as a Main Component:

Sun Wet, Sun Energy, MSO surfactant, Sun Control, Sil Kick, JLB Oil Plus Improved, and Brewer basal oil. Due to their ability to promote the absorption and translocation of the herbicide into the plant, MSO-based adjuvants are very successful at improving the efficacy of herbicides. 

  • Brewer products with MSO as a minor component:

Cide Kick II Methylated, JLB Oil Plus, Poly Film R, and Red River Sunrise.Although these products contain less MSO, they nonetheless offer many of the same advantages, while increasing wetting and spreading capabilities. These can be used when issues such as leaf burn are problematic for non-target plants.

For more than 40 years, Brewer Products has been a reputable brand when it comes to aquatics and agricultural adjuvants. Leading agronomists and business experts endorse their products, which are widely utilized by farmers and applicators across the United States.


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  2. Peterson, D. E., & Archer, D. W. (2011). Chapter 1: Weed management principles. In Herbicide handbook (pp. 1-13). Purdue University.
  3. Reddy, K. N., Rimando, A. M., Duke, S. O., & Nandula, V. K. (2008). Aminomethylphosphonic acid accumulation in plant species treated with glyphosate. Journal of Agricultural and Food Chemistry, 56(6), 2125-2130.
  4. Soltani, N., & Nurse, R. E. (2018). Influence of adjuvants on herbicide efficacy. Weed Technology, 32(1), 1-11.
  5. United States Environmental Protection Agency. (2018). Pesticides industry sales and usage: 2008-2012 market estimates. Retrieved from
  6. Wolf, T. M., & Hall, L. M. (2018). Adjuvants for herbicides. In Herbicides and environment (pp. 67-85). IntechOpen.
  7. Yang, Y., Li, J., Li, J., Li, H., Liu, J., & Li, J. (2019). Environmental effects of glyphosate and glyphosate-based herbicides: A review. Journal of environmental management, 240, 505-516.

Brewer International has been a leader in land and water chemistry since the 1980s and for over 40 years has proudly served its national and regional distributors.

Our products are used widely across the United States in agriculture, aquatics, forestry, rights of way, and land management.

Our customers trust our dedication to quality ingredients, tried and true formulas, and positive outcomes.

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