CARROT GROWERS should switch to narrow fan jet nozzles to improve Sclerotinia control and reduce water volumes, Syngenta has advised.

Using the 65o flat fan nozzles for Amistar (azoxystrobin) applications means spray can more easily penetrate the crop canopy to reach the stem base and root crown, the company said.

Using bigger nozzles (08 nozzles at 50cm spacing), also improves penetration, said the firm’s Tom Robinson.

Syngenta trials last year found that this combination of wider spaced 08 65o flat fan jets deposited 40% more Amistar at the carrot base in mid-August applications, compared to closer spaced (25cm) 04 nozzles.

“While air induction nozzles and twin-caps with conventional nozzles work well for Amistar sprays on carrot tops to prevent Alternaria, switching to narrow fan jets for better canopy penetration is far more effective for Sclerotinia.”

Using such nozzles could also help cut water volumes by half, claimed Mr Robinson. Many growers still apply 600 litres/ha, but in practice half this volume will be effective and could double sprayer output, he said.