Weeds are getting out of control on some unseeded and seeded fields too wet for the ground sprayer. This is especially true on fields that didn’t get a pre-seed burnoff. Aerial spraying may be the best option even at this early stage of the crop. Here are the options for aerial herbicide application in canola:
- Roundup WeatherMax is the only glyphosate registered for aerial application at this crop stage, but use is subject to certain conditions which are outlined in detail on the label. (Many others are registered for pre-harvest.) WeatherMax is also the only glyphosate registered for aerial application on unseeded fields.
- Liberty (glufosinate) is registered for aerial application at this stage. Remember, Liberty works best at higher water volumes.
- None of the Clearfield herbicide system products are registered for aerial application on Clearfield canola.
- Poast and Assure II have aerial labels.
- Centurion has an emergency use registration for aerial application.
Benefits of aerial application: In many regions, weeds are ahead of the crop. In other cases, fields are unseeded but growers want to control the weeds before they get too big and start to set seed. If that’s the case and fields are too wet for the sprayer, then aerial spraying may pay off. Aerial spraying also avoids wear and tear on sprayers and on the field when conditions are wet. Under these very wet conditions, ground sprayers can leave deeps ruts to contend with in subsequent spray applications and at harvest, while destroying the crop in those tracks. And getting a sprayer unstuck can be a long, messy job.
Downsides to aerial application: Buffer zone requirements for aerial application are substantially further from sensitive habitats than buffers for ground application. For Liberty, for example, the buffer zone for aerial application is 30 metres from non-target plants and animals compared to a 1 metre buffer for ground application. Aerial application also represents another cost for a crop that does not have the profit potential it had before the delays and the moisture stress. On that note, in very wet conditions, growers should make sure the crop has recovered before stacking on the extra expense of aerial weed control.