Water quality impacts the performance of all pesticides, especially those farmers rely on the most. In herbicide applications, poor water quality can reduce efficacy by as much as 50% if left untreated. That amount of loss is something farmers can’t afford when certain herbicides are already in short supply. Fortunately, we can easily correct the causes of poor water quality by monitoring our water sources for certain traits and including water conditioners in our applications.

Poor water quality can result in antagonisms, active ingredient decomposition and/or formulation incompatibilities. Antagonisms are hard to see with the naked eye, and they are usually only discovered when weed control is compromised. They slow herbicide activity and reduce the degree and rate of active ingredient uptake into and/or translocation throughout the plant. Active ingredient decomposition is also difficult to see in the mix, and it is most commonly associated with insecticides and fungicides. On the other hand, formulation incompatibilities are very evident in the spray mix. They reveal themselves through separation or clumping in the tank, clogging in the nozzles and filters, or color changes.

In order to correct these problems, we have to identify what causes them. Below are the most common traits used to determine water quality:

  1. Hardness: the total amount of dissolved cations in water. Metal cations, typically calcium and magnesium, bind with herbicides to produce antagonisms. Hardness is problematic with herbicides such as glyphosate, glufosinate, paraquat, 2,4-D amine and clethodim.
  2. Iron Antagonisms: known to impact weed control when using glyphosate and dicamba.
  3. pH: the measure of acidity (pH < 7) and alkalinity (pH > 7) in water. A pH of 7 is neutral, with 3-6 considered optimum for most pesticides, but this varies depending on the product.
  4. Carbonates/Bicarbonates: go hand in hand with pH, impacting pesticides when high levels are present in water. High carbonates/bicarbonates greatly impact the efficacy of glyphosate, 2,4-D, clethodim and sethoxydim.
  5. Sodium: becomes an issue when combined with carbonates and bicarbonates. This is typically measured to determine the suitability of water for irrigation, but it can also interact negatively with certain pesticides.
  6. Total Dissolved Solids (TDS): the total amount of minerals dissolved in water. It is especially important to monitor TDS when water is sourced from creeks, rivers, lakes, ponds, etc., and if the water is brown. When herbicides like glyphosate and paraquat react with these soil particles in the water, they are rendered ineffective.

The proper use of water conditioners can manage these traits to maximize pest control, aid in resistance management, and help prevent time-robbing application issues. To find the right water conditioner for your tank, you have to first identify the problems in your water. Helena encourages farmers to pull water samples and test water quality prior to spraying and/or irrigating. AquaLenz® is Helena’s Advanced Water Analysis service that aligns water quality issues with water conditioner recommendations. With this knowledge in hand, you can find the right water conditioner for your tank mix and have more confidence in your application’s success.

To ensure you get the greatest return on your herbicide investment this season, find a Helena location near you to learn more about AquaLenz and Helena water conditioners.