What to do – and what not to do – when using adjuvants

How to get the most out of your crop protection products

Adjuvants help keep pesticide ingredients suspended in spray water and improve adherence to what you are targeting.

Most pesticide labels include a section indicating what type of adjuvants will help you get the most out of your crop protection applications.

These labels feature language such as “required,” “recommended” or “can be used” to help you understand which adjuvants are essential to your mix and which ones are optional. But it’s not as simple as it appears.

Expert Brent Flaten, crops extension specialist with the Saskatchewan Ministry of Agriculture, provided some answers on how best to use adjuvants.

Flaten says adjuvants are grouped into “activators or spray modifiers” that include surfactants and oils to keep the pesticide ingredients suspended in spray water and improve adherence to weeds/crops/insects. Other adjuvants improve performance by adjusting spray solution pH, lowering drift potential, or compensating for water characteristics such as hardness.

The adjuvants that absolutely must be added will be listed on the product label, and Flaten says “do not add anything beyond what’s listed on the label to be added without contacting the manufacturer. That includes micronutrients, which can affect performance of the product or due to chemical interactions could lead to crop burn.”

Sometimes the people answering the manufacturer’s toll-free lines, notes Flaten, may have limited field experience. Therefore, establishing a relationship with a local technical representative, who has a wider scope of in-field knowledge and experience, might be a good idea for some trustworthy advice.

“At the same time, you should double-check any advice with the manufacturer,” he adds, “regarding third-party sales pitches, as that salesperson may try to sell you a pH adjustor to improve performance, but it could very well already be in the formulation. You don’t want to waste money or negatively affect performance.”

Rory Cranston, Saskatchewan-based agronomic systems manager (cereals) for Bayer, says, thankfully, it’s not very common a pH adjustor would need to be added to a product where there was not a recommendation on the label to do so.

Also, if you have farm water that’s very acidic or basic for tank-mixing, “that would likely be a situation where an additional pH adjustor is required, but that would be something that would affect all products,” he adds.

Cranston explains Bayer and other companies do their best to make products that are as easy to use as possible (everything that’s needed is included in a single jug). He also notes Bayer tests all its new products with well-established adjuvants (mostly surfactants) for the three standard factors, which are chemical compatibility (that is, they don’t gel when put together), efficacy and crop safety. However, with newer surfactants, Bayer doesn’t have data on these factors and therefore can’t recommend their use with new Bayer products.

In terms of seeking advice, Cranston says whoever recommends a given surfactant with a given product must be the party prepared to accept responsibility and provide support if anything goes wrong. “I echo the guidance to talk to the manufacturer about adjuvants,” he says. “If you are talking to a trusted advisor or viewing information online, however, make sure the source can offer you proof on all three factors. Sometimes there is only compatibility that’s being referred to, but efficacy and crop safety matter.”

He also says no matter the surfactant included with or added to a product, proper spray management is key — using the right nozzle, speed, boom height, spraying in suitable environmental conditions, and so on.

Adjuvants improve a crop protection product’s activity by getting the product to the plant, on the plant and inside the plant, leading to better overall absorption. They also help pesticides perform consistently and to their full potential, says Shelby LaRose, proprietary products manager at Loveland Products Canada, based in Saskatchewan.

“Adjuvants are not the ‘silver bullet’ for ideal spray solutions but they will keep your crop protection product solution on-target and working in the most efficient and effective way,” says LaRose.

About the author


Treena Hein is a freelance writer specializing in science, tech and business trends in agriculture and more.



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