The previous adjuvant series post explained barriers of entry and how certain kinds of adjuvants work to break through. To review:
- Guar based adjuvants will aid in leaf angle barriers
- Oil based adjuvants and surfactants aid in leaf hair barriers
- Adjuvants that can solubilize aid with thick waxy leaf surfaces
How do the adjuvants successfully break through weed barriers? The explanation below will save you headache down the road. Choosing the right adjuvant will give you a beneficial effectiveness that saves you money in the long run.
Nonionic Surfactants (NIS)
- Increase activity of organic herbicides
- Affect the spray solution, cuticle surface, and cuticle layers
- May improve pesticide effectiveness by: decreasing surface tension, slowing drying time, increasing penetration, or allowing for better mixing
Essentially, NIS reduces surface tension on plant surfaces, enabling a better spread. They accomplish all this by combining water-loving and oil-loving properties in the same molecule. This is called the hydrophilic-lipophilic balance (HLB). This is a necessary guide in knowing adjuvant effectiveness with certain products. An HLB of 1= oil loving and HLB of 22= water loving. A higher HLB will work better with water based pesticides and vice versa.
Crop Oil Concentrates (COC and HSOC)
- Function as spreaders
- COC- 15-20% surfactant/emulsifier and 80-85% petroleum oil
- High surfactant oil concentrates (HSOC)- 60% oil and 40% emulsifier/surfactant
- The blend of the two result in maximum herbicide dispersal
- More effective with high temps and low humidity
The oils ultimately improve penetration and the ability to spread.
Methylated Seed Oil (MSO)
- Refined oil concentrates from soybean, cotton, sunflower, corn or rape seed
- Better solvents and highly active
- Better for large or drought stressed weeds
- Excellent spreaders with a high boiling point which prevents evaporation of product off leaf surface
- 90% oil and 10% emulsifier/surfactant
MSO increases the uptake and translocation of the herbicide very effectively.
Novus Ag carries Medallion Quality Adjuvants from Rosen’s Inc. and would love to assist you in any adjuvant decisions this growing season. Please contact an Associate Partner for more information on these different families of adjuvants. Ensuring proper usage with your pesticide applications, will better cover your expenses at the end of the day.
Referenced from: Rosen’s Inc. Medallion Quality Adjuvant Guide