More than half of U.S. corn, soybean and wheat growers have changed their herbicide tank-mix strategies within the last three years, according to a survey of 2013 Commodity Classic attendees. Primary shifts included using new, different or more herbicides in the same spray tank.

The survey, sponsored by DuPont Crop Protection, polled 130 thought-leader growers in early March. Nearly 67 percent of growers surveyed said they or a farm employee handle all herbicide tank mixing on their farm. The rest said they rely on custom applicators to do some or all of the job.

The number one reason given for changing tank mixes was dealing with or preventing herbicide-resistant weeds. Ranking close behind was the desire to improve crop yield by reducing weed competition.

"The survey results are consistent with what we've seen in the field," says Mike Meyer, DuPont Crop Protection field development manager based in Norwalk, Iowa. "Growers are taking the risk of herbicide-resistant weeds seriously and are taking steps to address the problem.

"To reduce issues with herbicide resistance, many growers and applicators are building tank mixes that include herbicides with residual control and different modes of action. Those changes not only address herbicide-resistant weeds, but also reduce overall weed competition, including early weeds and second flushes of weeds that can have a significant impact on yield."

Change does not always come easily. The survey revealed several grower concerns regarding tank mixes. The number one worry­ called extremely or moderately challenging by the respondents ­ was the ability to correctly mix and apply herbicides to prevent crop injury. Other points of concern included accurately measuring herbicides, knowing how much product to use, difficult tank cleanout, clogged spray nozzles, time-consuming processes and confusing product labels.

"The fact that so many growers do their own tank mixing and herbicide application is a reminder that companies like DuPont must continue to focus on making our products not only as effective and safe as possible, but also easy and convenient to mix and apply," says Meyer.

"Growers and retailers have adopted tank-mixing advancements that take significant steps toward the goal of easier, more confident tank mixing. DuPont offers corn, soybean and wheat herbicides in dry soluble formulations, including DuPont PrecisionPac custom blended herbicide solutions, which eliminate measuring on the farm. In addition, the DuPont PrecisionPac multi-product dispensing system will provide a customized herbicide solution for each field's weed control needs and sprayer tank.

"By helping to streamline the tank-mixing process with new ideas like those, we're helping take some of the worry out of a grower's tank-mixing experience and improving yield potential through more effective and reliable weed control."