Get the best from beet in difficult year

Mastering disease control is crucial for growers to ensure sugar beet canopies keep photosynthesising efficiently this season.

Speaking at a recent BASF webinar, experts gave a summary of the likely disease threats which could prevent growers from achieving maximum root weight and optimum sugar content.

The key foliar diseases for sugar beet this summer were likely to be powdery mildew, rust and cercospora leaf spot, said Mark Stevens, head of science at the British Beet Research Organisation (BBRO).

Yield potential

With no reports of any early foliar disease, Prof Stevens reminded growers that it would still be present. Farmers should limit the impact of foliar disease by reacting as soon as it appeared in the crop, with broad spectrum fungicides critical for control.

Sugar beet often gains up to 40% of its yield potential from 1 September onwards.

“If we can keep the canopy healthy throughout the summer and into autumn, we can hopefully keep it photosynthesising at its most efficient rate.”

Powdery mildew could reduce yields by 20%, said Prof Stevens. Growers should manage the disease as soon as it was visible, he added. Varietal resistance should also be checked to guide fungicide programmes.

Rust can decrease yield by 15% and tends to like slightly cooler conditions, with growers likely to start seeing symptoms of this disease from August through to October, added Prof Stevens.

Favoured by warm and wet conditions, Cercospora leaf spot has recently become established as a prevalent foliar disease in the UK. Describing it as a big concern, Prof Stevens said it was now more common.

“The BBRO now monitors for spores of the disease, via a new project, through May and August alongside producing a forecasting model for growers to show which crops are at the greatest threat each day.”

Biofertiliser boost for canopy formation

Sugar beet crops slow to get going during a challenging  season have benefited from early biofertiliser application to promote canopy formation.

Delayed drilling in wet soils and poor early conditions left many crops languishing early on, says Syngenta sugar beet specialist Jonathan Ronksley. The wet winter also depleted soil fertility, particularly on prime silty-sand land.

Early nitrogen is essential for rapid leaf growth, says Mr Ronksley. “During rapid leaf expansion, sugar beet takes up 4-5 kg of nitrogen per hectare every day. Compensatory growth in backward crops puts even greater strain on resources.”

Biofertilser Vixeran delivers nitrogen to the crop in small but constant amounts through the season. This helps to maintain growth and development, while avoiding detrimental effects of excessive nitrogen inputs, which reduce sugar content.

Vixeran is based on the highly efficient nitrogen-fixing bacterium, Azotobacter salinestris. Applied as a foliar treatment, it multiplies rapidly across the leaves and the roots, supporting the crops nutritional requirements throughout the entire season.

Sugar beet trials in a commercial Yorkshire crop last year saw a 15% yield uplift to 135t/ha, from a single Vixeran application, compared to the farm standard of 116t/ha. Sugar content was 17.19% in the treated crop, compared to 16.71% in the intreated beet.

Mr Ronksley advocates applying Vixeran from early crop establishment until full ground closure, recommended at growth stages 14-18.

“The whole area received the farm standard treatment of 150kg N/ha, demonstrating the benefit of the Vixeran supplying additional nutrient that’s taken up and utilised by the crop,” says Mr Ronksley.