This season’s sugar beet crops are under pressure from prolonged drought conditions across large parts of the eastern counties. With growth checked by the ongoing dry weather it’s now essential to extend the growing season for roots to bulk up and add sugar, advises Syngenta Technical Manager, Andy Cunningham.

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“Maintaining green leaf area for as long as possible will be paramount in growers’ decisions for fungicide programmes this season,” he advocated. “Priori Gold gives the combination of effective disease protection and the physiological advantage of green leaf retention.”

British Sugar agronomists have reported healthy crops can put on an additional 25% of adjusted yield from mid-September, with sugar content increasing by 0.2-0.4% a week through to November.

Powdery mildew has been at high risk for some time, favoured by the hot dry conditions, pointed out Mr Cunningham. “But as day length now shortens and leaves remain wet with dew for prolonged periods overnight, there’s also increased risk of rust developing very quickly.”

That would be further exacerbated by irrigation of crops during the dry weather, or any isolated rain showers that occur. Rust is already highly prevalent on crops in the north and west, where conditions have been wetter and persistent strong winds may have prevented timely fungicide treatments.

Rust can be one of the most challenging diseases for fungicides in sugar beet. With Priori Gold (also marketed by Syngenta as Angle), crops get the combined disease protection of difenoconazole and azoxystrobin for rust, powdery mildew, Ramularia and Cercospora, as well as the renowned green leaf retention of the strobilurin active.

The positive aspect of the hot, dry weather is that the risk of Ramularia has reduced, highlighted Mr Cunningham. However, since the disease can still hit later in the season, growers should be aware of the need for persistent fungicides or a later application to prevent early defoliation, he warned.  

In previous seasons, Mr Cunningham reported a two or three-spray strategy has consistently shown the highest yields and best returns. “For most growers two sprays are still going to pay dividends this season.

“But if they do opt for a single treatment, it’s crucial that it is as timely as possible and they seek to get both the disease control and green leaf retention offered by Priori Gold. Retaining healthy green leaf will prove a positive bonus for ease of harvesting in the autumn.”

Syngenta is also conducting further sugar beet trials this season to support the registration of a new fungicide that would give growers and agronomists additional flexibility and better targeting of all beet diseases in an extended diseases control strategy.