There’s still time to spray Atlantis WG in 2013 - and growers still waiting to make applications should grab the opportunity to benefit from greater black-grass control and preserved yield, advises independent agronomist Dale Senior.
Controlling black-grass this side of Christmas reduces the time the grass-weed has to steal water, light and nutrients from crops. Trials by Bayer CropScience show that delaying application from autumn into spring results in an average of 1t/ha lost. “By applying Atlantis WG now, it will conserve yield and be more effective; black-grass is as small and vulnerable as it is going to be, ” says Mr Senior, of J. K. Senior and Sons.
The Yorkshire-based agronomy group has been advocating autumn applications of Atlantis WG for over eight years, with excellent results. “At this time of year, we’ve already applied Atlantis WG to those fields with high or resistant populations, and are now picking off the remainder. “Black-grass germination is beginning to peter out as winter closes in but clods are continuing to break down and release fresh seed and seedlings, so there’s an argument for adding a residual to the tank-mix,” he adds, particularly where pre-em performance was lacking.
Recent rains have created ideal conditions for residuals, Mr Senior notes. “The rain has moved finer particles across the soil as it flowed, smoothing the surface to create a seal and the ideal conditions for applying post-emergence tank-mixes. This is a considerable boost to residual herbicides, which rely on the creation of a continuous layer through which germinating black-grass must grow. With nature lending a helping hand to residuals, the focus for application technique should be on the Atlantis WG.”
Bayer’s commercial technical manager John Cook says short winter days have an optimal spraying window. “In early winter, allow just enough time for the dew to lift and then stop spraying two hours before dew point in the afternoon. This lets leaves dry before application and gives Atlantis WG the time it needs to become rainfast.
“Flat-fan nozzles work well in a wide range of conditions. Aim for a fine to medium spray and a forward speed of no more than 12km/hr,” he adds. Where canopies are open and autumn-like a water volume of 100L/ha is acceptable, but for non-optimal situations (e,g. uneven ground or sub-optimal spray conditions) increasing the total spray volume (up to 200 L/ha) can result in more reliable control. “Only when black-grass has stopped growing should sprayers be put on stand-by and even then, there may be good spray days at the end of winter and into early spring; it’s a good idea to keep the sprayer at the front of the shed,” he says.