Carrot growers using the fungicide Amistar to control Sclerotinia are being advised to switch to a narrow 65-degree flat fan jet nozzle for best results.

Research from Syngenta, a world-leading agribusiness, said the narrow spray angle achieves the best results for treatments targeted at protecting the stem base and root crown beneath the carrot’s canopy.

They say the effect can further be enhanced by using larger nozzles at a wider spacing on the spray boom.

Syngenta application specialist, Tom Robinson said: “The bigger nozzle orifice produces bigger droplets which get down to the stem base and the root crown more effectively.”

Trials in mid-August showed the larger 65-degree flat fanjets deposited over 40 per cent more Amistar at the carrot base and doubled the result of conventional 110-degree flat fan nozzles.

John Lyon, manager of carrot grower Watton Produce who undertook trials with Syngenta last year said: “Sclerotinia remains the key pathogen to control for the crops being covered for winter lifting.

“But using Amistar to keep the green leaf and stem healthy for longer into the autumn also increases the proportion that can be green top lifted, before we have to move to share-lifted harvesting; which significantly reduces field losses and the amount of soil carried into the pack house.”