Nozzle choice for controlling small blackgrass
Controlling small blackgrass plants in the autumn is one of the biggest spraying challenges, not least because the level of control must be very high in order to reduce the blackgrass population.
Looked at from above, even a high population of blackgrass plants does not present very much leaf area to receive spray droplets.
It is important to follow label recommendations on water volume and spray quality but equally important is the angle at which the spray hits the target leaves.
Research carried out by Silsoe Reasearch Institute has shown that an inclined spray works much better, depositing twice as much spray onto 1-2 leaf blackgrass plants.
Field trials using an 03 flat fan VP nozzle with a 40 degree forward incline* have confirmed this.
The photo above shows blackgrass regrowth in the following crop of Linseed. Alternate boom widths were sprayed with the same product at the same water volume but through either a standard VP nozzle or Syngenta's Hawk nozzle which is inclined at 40 degrees. There is much less re-growth in the areas where the inclined Hawk nozzle was used, indicating that blackgrass control was much higher in these area - remember the only difference was the spray incline!
* An inclined VP can be achieved using Syngenta's Hawk nozzle or a Hypro flat fan VP nozzle selected for the desired speed and water volume in a TwinCap. TwinCap offers the option of either two 30 degree inclined sprays (useful for maintaining finer spray quality at higher water volumes) or a single 30 degree inclined spray when used with a blanking nozzle.
Hypro TwinCap (EF3 version) part # 152607TC
Blanking nozzle part # 30KBLANK