Adjuvants have come a long way in the past decade — evolving from simple crop oils to today's complex microencapsulated drift retardants. Their role at the retailer level is more sophisticated as well, with adjuvants marketed for specific crop protection products and use situations.

“Within the last five to six years, use of adjuvants to increase crop protection products' efficacy has become vitally important,” says Chris Klinkenborg, agronomy production specialist with Eastern Farmers Cooperative in Baltic, SD.

Ongoing research into the role adjuvants play is leading to better products and improved crop protection. Today, the majority of crop protection products receive an adjuvant addition before application.

“We use adjuvants more often as we continue to discover how much better they make the product perform,” Klinkenborg says. “It's something that our customers can see in side-by-side field trials.

“Our relationship with our customers is one of rapport and trust,” Klinkenborg continues. “They take our advice on adjuvant usage, but education plays an important role too. Every day more and more customers are asking how adjuvants work and why they should use them.”

New adjuvant products usually are introduced by key progressive growers. “These are customers who are looking for ways to improve the productivity and profit in their operations. But equally important, they are growers that other members of the farming community respect and look to,” Klinkenborg says.

For example, Agriliance's new Interlock is the next generation of adjuvants that encapsulate the active ingredient plus ammonium sulfate (AMS) for optimum herbicide efficacy with reduced drift. “Once our growers saw the product applied to glyphosate-tolerant soybeans for weed control, without damage to the corn planted beside it, they were sold,” Klinkenborg says.

One important aspect of adjuvants for the grower and retailer is profitability. Klinkenborg notes that, as a profit center, adjuvants are a win-win situation.

“Adjuvants improve the efficacy of the grower's crop protection product with minimal cost, while providing the retailer with a profit center,” he says. “While adjuvants can't make up the millions of dollars that have been lost in the crop protection market, they can add profit to the retailer's business.”

According to Klinkenborg, fewer and fewer research dollars go towards new crop protection products while natural weed selectivity marches on. “In some instances we'll be looking at glyphosate as a tankmix partner and depending on adjuvants for value,” he says.

“At WFS we see adjuvants as a very necessary part of the crop protection product picture,” says Rick Haase, crop production manager for Watonwan Farm Service, headquartered in Truman, MN. He adds that many current crop protection products can't perform to their potential without a quality adjuvant.

“Eighty-five percent of the crop protection cost is in the chemical, while 15% is in the adjuvant,” Haase says. “It would be a shame for growers to spend the 85% while ignoring the 15% that would make the product work.”

In an effort to bring top-quality adjuvants to its customers, WFS has partnered with Rosen's to add the WFS logo to a crop oil concentrate.

“The majority of customers understand the important role adjuvants play in crop production,” Haase says. “For retailers it's good business to explain the products, their roles and why we recommend the choices we do, on a yearly basis.”

Haase says side-by-side field trials with crops treated with adjuvants and untreated plantings clearly show the advantages of adjuvant use in weed control. “Seeing is believing for growers,” he adds.

The evolution of adjuvants continues as combination products and new delivery systems are introduced. “We started testing Zenith, a new dry bonded adjuvant, after its introduction three years ago and found that it improved our herbicide performance and eliminated many off-target issues,” Haase notes. It also covers the majority of adjuvant requirements for most herbicides and insecticides.

Zenith is available through a bulk delivery system called DDS 2000 designed to improve handling safety and eliminate container disposal. Haase says it also allows WFS to treat customers' water in an efficient and timely manner.

“A DDS system allows us to add Zenith when loading water and then add the crop protection product in the field,” he explains.

The combination of products including adjuvant mixes becomes more important when treating hardened-off weeds or on second applications. “In these types of situations, against tough weeds, the adjuvants enable the crop protection product to perform at top efficacy through enhanced absorption and plant uptake,” Haase says.

With customers who grow crops ranging from celery and squash to blueberries and soybeans, the agronomists at Vriesland Growers Co-op in Hudsonville, MI, call on an array of adjuvants to enhance crop protection products.

“In our business, adjuvants are used with fungicides, insecticides and herbicides,” says Dan Harrigan, agronomy manager at Vriesland Growers Co-op. “Every pesticide application has at least one adjuvant in the mix.”

Different crops require their own unique adjuvants or adjuvant combinations. “We rely on approximately 12 different adjuvants based on their use and the type of crop we're spraying,” Harrigan says. Many adjuvants are also labeled for multiple crops.

Different adjuvants can be added to serve specific purposes, such as acidifiers to affect pH levels for fungicides and insecticides, resulting in longer activity; stickers for plant retention; and silicon to make the spray wetter for better penetration.

For example, Sylgard 309 silicon surfactant from Wilbur-Ellis provides extra wetting action. “This wetting action is crucial when applying insecticides to onions to reach thrips that tend to hide deep in the neck of the bulb,” Harrigan says.

“Growers of high-value crops like vegetables, for example, are more likely to use multiple adjuvants in a complex tankmix containing a fungicide, insecticide and foliar feeding,” Harrigan points out.

Multiple spray agents in a tankmix also can create compatibility issues. Again, adjuvants are used to adjust pH levels and assure the best possible uptake for all the spray agents.

“There are so many possible tankmixes with each crop that making sure all the key adjuvants are in place is a very important part of the spray application,” Harrigan says.

Vriesland Growers' customers rely on the co-op for the proper adjuvant addition to the spray mixture.

“More and more growers are aware that acidifiers help with pH levels, improving the half-life of the spray product in the field,” Harrigan says. “As spray costs increase, growers are concerned with getting the most bang for their buck.”

He says that while growers watch their spray costs closely, they don't price out adjuvants the same way they do pesticides.

“Even though adjuvants are only 5 to 10% of the spray cost, they provide us with an important profit center,” Harrigan says, “especially in the competitive Roundup Ready situation.”

Looking to the future, Harrigan thinks that adjuvant manufacturers will begin offering incentives to retailers to buy their entire product line. “There are a lot of basic manufacturers with competitive adjuvant products right now competing for market share,” he says.

With the invasion of Asian soybean rust into the U.S., growers will be relying heavily on retailers and applicators to help them protect their crops and their investment in the fungicides they use to control the disease. Adjuvants can play an important role in that battle if they are carefully selected.

The majority of adjuvants on the market today are formulated to enhance the biological activity of herbicides, not fungicides. Ordinary spreader-type adjuvants that were formulated to improve coverage leave deposits that may dry too quickly for systemics. Sticker-type adjuvants, designed to prevent wash-off, may not provide adequate coverage for protectants and may tie up systemics during phase behavior. In fact, using surfactants that were developed for use with herbicides in a fungicide tankmix could not only affect fungicide performance, but could also cause crop safety issues.

For the last several years, Jim Reiss, vice president of agriculture, Precision Laboratories, has been testing adjuvants specifically designed to enhance the performance of both systemic and contact fungicides and their tankmixes. The company's newest product, Protyx, is its flagship fungicide formulation.

“Dealing with rust and other leaf diseases is far more difficult because the ‘fungicide-formulation-fungus-adjuvant-host plant’ interaction is much more complex,” Reiss says. “Our research in major row crops and cereals has shown statistically significant differences in plant health and yield depending upon the adjuvant-fungicide mix. In fact, ordinary surfactants haven't demonstrated the value that our new adjuvant technologies have shown.”

That's the coming challenge for retailers and growers — finding the right adjuvant that will provide significant returns on fungicide efficacy in fighting leaf diseases and simultaneously provide improved plant health, yield and net profit per acre.

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