Spray at right angles
Spray at right angles
USING angled spray nozzles at earlier stages of canopy development in cereals will improve the impact of contact-acting fungicides and lead to cost savings, HGCA research suggests.
Paul Miller of Silsoe Research Institute is examining how fungicide performance can be maximised by varying applications according to canopy characteristics.
At earlier growth stages, such as GS32, spray delivery will be enhanced by altering the angle of the nozzles to account for more open canopies, he says.
Results show angled nozzles delivered 22% more volume to the canopy compared with straight nozzles. On thicker canopies at GS39, the effect was far less pronounced.
"Most farmers will apply, for instance, 150 litres/ha at three-quarters dose across a whole field and at all growth stages. But the results clearly show that altering the spray angle, particularly at earlier growth stages, can improve performance as well as have cost-saving implications.
"Substantial changes in green leaf area in the early stages of canopy development have been recorded in fields due to slug damage and soil type. We are looking at refining the system to measure leaf area so that we can take more account of variability." *