By Sithin Mathew and Eric Yu et.al
Herbicides often require the use of adjuvants to maximize weed control efficacy and minimize application-related risks. Although some herbicide formulations contain built-in adjuvant packages, few are designed to optimize performance across the wide range of environmental and application conditions. Therefore, the applicator often needs additional adjuvants to optimize the herbicide application for the specific conditions of the area being treated.
The most commonly used adjuvants can be grouped into four categories: 1) activator adjuvants [e.g., nonionic surfactant (NIS), crop oil concentrate (COC), and methylated seed oil (MSO), etc.], 2) water conditioners [e.g., ammonium sulfate (AMS), and volatility reduction agent (VRA), etc.], 3) spray solution modifiers [e.g., antifoam agents, and drift reduction agents (DRA)], and 4) adjuvant mixtures. Adjuvants can enhance herbicide activity by improving spray retention, spreading, penetration, absorption, and overall weed control. For more information on adjuvant use and function in herbicide applications, see the following Crop Protection Network article. Additional information on the history of adjuvants and best management practices can be found in this Crop News article.
Correctly using adjuvants is important because using an incorrect type or rate can result in poor weed control and/or crop injury. The appropriate use of an adjuvant, including adjuvant selection and the amount required, may vary by herbicide and environment. The herbicide label should be the first place to look to determine if an adjuvant is required, the correct type needed, and the recommended rate. If multiple herbicides are being applied, consult the label of each product, paying particular attention to guidance on adjuvants, tank mix partners, and any restrictions or “do not” statements. When label directions differ among products, follow the most restrictive label requirements to ensure compliance and minimize the risk. In this article, we summarize adjuvants commonly recommended for widely used post-emergence herbicides in soybean
Source : umn.edu