Bayer Product Spray Applications Quick Reference

There are many different things to consider when spraying pesticides that can impact efficacy including water volume, spray quality, temperature, and pressure. This document can be used as a quick reference for spraying Bayer products. For complete instructions, always refer to the product label.

Herbicides

Table 1. Herbicide modes of action, minimum water volumes with low drift nozzles and maximum spray quality. Note that higher volumes may allow for coarser sprays.¹

Hard water can affect herbicide performance. Heavy loads of calcium (Ca) and magnesium (Mg) in the farm water source can significantly reduce the performance of glyphosate. Other chemistries affected by hardwater include glufosinate and 2,4-D. If weed control is repeatedly poor, water hardness should be tested.

• >700ppm Ca and Mg – issues may arise if using rates lower than 0.67L/acre of Roundup WeatherMAX^® with Transorb^® II Technology or Roundup Transorb^® HC Herbicide
• 500-700ppm Ca and Mg – may experience variable results
• <500ppm Ca and Mg – this is acceptable

Ammonium Sulfate (AMS) can be used to combat hard water that is heavy in calcium. It doesn’t influence the other hard water elements such as magnesium and iron.

Temperature affects herbicide performance by effecting how plants grow. In general, herbicides tend to work best in warm, mid-low humidity, and sunny conditions when plants are actively growing. Post emergent herbicides work best between 15⁰C and 28⁰C.²

• Plants growing under cooler conditions are less able to take up the chemical and convert it to other forms. The same can be said for night-time applications.
• Cooler temperatures: If air temperature is going to dip below 5⁰C a day or two before or after application, crop injury may occur and weed control will be reduced. Watching the forecast for frost or cooler temperatures is important when planning your herbicide application.²
  
  

  Temperature

  Group	Very Important	Important	Less Important
  1	X
  2	X
  4		X
  5		X
  6		X
  9			X
  10	X
  27		X

  
  
• In general, avoid applying in severe heat conditions (hot and dry) as the rate of chemical evaporation increases reducing product efficacy. High temperatures increase the potential for significant crop response.

Temperature Inversions: small droplets will remain suspended in a concentrated cloud. Chemistry applications should be stopped during this time due to increased risk of off-target movement and drift.

• Do not apply during periods of dead-calm. Wind recommendations 5 to 15km/hr (2-10 mph)

Product Ground Application Calibration

When applying pesticides, it is important to select the correct nozzles for the right situation. Inaccurate pesticide application rates, spray patterns and droplet size can lead to the movement of pesticides away from the targeted area and reduce pesticide effectiveness. Minimizing drift is especially important for herbicides. Prior to pesticide application, every sprayer should be thoroughly calibrated before the first use of the season, and the calibration should be checked periodically throughout the season whenever a new nozzle configuration and application pattern is employed.

The following table summarizes guidance on appropriate nozzle types, droplet, and PSI for Bayer products. As a reminder, vigorous, continuous agitation is essential for proper mixing throughout filling and spraying operations of all product tank mixes. Always read and follow label directions.

Table 2. Nozzle and pressure recommendation for ground application of common Bayer Pesticides.

*With all the products listed, PSI should be kept above 30. Spray pattern loss can occur if pressure is less than this.