Spraying Dicamba - What meter do you need. Keeping it simple.

  • Check readings regularly when spraying
  • Log your data
  • Protect your crop - you want Dicamba on your crop, not to miss it.
  • Protect your neighbors crop - Spray at the wrong time, and it could wind up in the wrong place.
  • Protect yourself - Lawsuits are plentiful right now in the courts. You need proof you followd the guidelines when you sprayed.

There have been over 2,200 complaints with Dicamba being the suspect in 2017. - Farm Journal, September 2017

According to the XtendiMax Application Requirements, you need to data log these 3 environment conditions from a reliable on site weather meter. Xtendimax is the brand name for Dicamba from Monsanto. Many believe this will get more stringent as damage and lawsuits continue, as it has in other countries like Australia that mandate Delta T readings. These 3 simple readings required don't tell enough to know and prevent spray drift.

This is the bare minimum as required to be logged:

  1. Wind Speed
  2. Temprature

Keep reading.

Manual Data Log

Manually log from the field with a compass in hand. Write it down and hope that holds in court. For this you can simply use:

  1. Kestrel 2000 - $94
  2. Personal Compass needed

Temperature is important: NEVER spray above 82F EVER! The vaporization rate at that temperature is lethal. If the actual Temperature is over 82F it is very very bad, but if the temperature is too low the reaction rate is insufficient for effectiveness. The minimum temperature is always dependent on the chemical being used. The Limit of 82F exists for all pesticides and herbicides but some may aerosol at lower temperatures so always know what you are spraying along with your conditions!

Most would agree, that's not enough.

Thermal Drift:

Thermal Drift is caused by an unstable atmosphere, and causes chemical droplets to be carried significant distances from the target area by thermal eddies. The measure of Delta T is increasingly being used by sprayers to measure spray conditions and prevent thermal drift. It is mandated in Australia and taught at all mandatory classes for spraying in AU. See More on Delta T and Pesticide Spraying with Kestrel.The safe Delta T range in Fahrenheit is simply 3.6-14.4. As Delta T increases, so does the effectiveness of the product, however it also comes at a risk. If, for example, the Delta T meter reading at 15.6- 16.3 it would have aerosolized which is incredibly dangerous and can travel miles. 3.6-7.2F is ideal, 7.2-10.8F is ok, 10.8-14.4F is marginal, and anything over14.4 is dangerous. Logging the wind direction is for spray drift, Delta T is for vaporization rates and droplet formation. But a key point often missed is that some wind is required, (greater than 2m/s generally) as calm conditions are also dangerous as droplets can remain suspended and then aerosol with more time spent in the atmosphere and then be deposited in an unwanted location, I.e. killing a corn field.

Dicamba and Inversion Layers (Stable atmosphere)

While an atmosphere that is too unstable is well understood a common error is spraying in conditions where a stable atmosphere (inversion) exists, this is especially dangerous in terms of spray drift considering the risks with Dicamba. As spraying in a inversion allows for a dicamba concentrated pocket of air to move and then settle on other crops passed by the inversion layer. For full details on an inversion layers and how it effects spraying please see: Surface Temprature Inversions and Spraying Fact Sheet.

Generally sprayers are taught to use your senses to detect Inversion layers however this can be difficult to prove. Thankfully there are measurements you can make starting the evening before spraying to check for the likelihood of a inversion being present prior to spraying:

  • Wind speed does not exceed 7mph in the evening prior or overnight
  • Large differences between maximum tempratures overnight
Simple Data Logger:

The Kestrel 5500AG meter logs the data for you. Your log is stored on your meter, which you can view on your iphone/Android, export to your computer as a CSV file and store for your records. You now have solid proof of your spray. The only thing more you need to do is record yourself your location, which you can do with your iphone/Android and screen capture that.

Go to the field, point your meter at the wind, hit the capture button and you have just officially taken these important features:

  • Date/ Time stamp
  • Wind Speed
  • Wind Direction (Built in Digital Compass)
  • Air Temprature
  • Delta T
  • Relative Humidity

The 5500AG Meter will also hold your data in the log. You can export via LiNK (bluetooth) by connecting to the app on iPhone / Android devices. You can view the data, choose how you want to export it, and/ or email it to yourself. You'll get it in CSV spreadsheet format to save.

Unfortunately the simple method while useful for checking for unstable conditions while spraying, it does not provide the sprayer with logs to demonstrate that an inversion layer was not present.

The Set, check, spray, store method :

The Kestrel 5500AG meter thanks to its made in the USA durability can also be used as a mini onsite weather station and log at regular intervals for each field prior to spraying.

Simply SET the Kestrel 5500AG in the Vane mount and attach to a tripod or using the portable tripod strap it to a fence the afternoon before spraying. This makes the 5500AG a portable weather station that is capable of keeping tabs on the weather throughout the evening and the night before spraying all completely unattended.

In the morning prior to mixing the chemical simply CHECK the Kestrel's data logs to ensure that the wind speed exceeded 7mph overnight and that there was not a large shift in temperatures during the night, if both these requirements are met do a check to see if a visible inversion is present also use sound and smell to verify.

Then check the Kestrel 5500AG for an unstable atmosphere. If neither an inversion or overly unstable atmosphere is present then you are ready to mix chemical and SPRAY. If conditions change, or you wish to double check conditions, the Kestrel 5500AG will already be setup collecting live environmentals while you spray. Plus if LiNK is installed, the LiNK feature enables the environmentals to be checked regularly simply be driving near the temporary weather station.

When you finish spraying, your log is stored on your meter, which you can view on your iphone/Android, export to your computer as a CSV file and STORE for your records. You may also pack up the Kestrel 5500AG and store it ready for set at the next spraying location.

Why Kestrel:
  • USA Made
  • Waterproof / Durable
  • 5 year warranty
  • Trusted name in handheld weather meters.