Monitor sugar beet for mildew and brown rust

The first signs of powdery mildew and brown rust have already been spotted in sugar beet crops across the main beet-growing regions.

“First fungicide sprays should be applied at full rate as soon as disease is seen in your crop or in your locality to ensure maximum yield,” said Pam Chambers, knowledge transfer manager at Broom’s Barn Research Centre in Suffolk.

More crops were drilled early this season, which may have brought the presence of foliar diseases forward, she noted. Again, like last year some rust spores are being seen a month early.

A second fungicide spray should be considered in high disease pressure situations and for late lifted crops – from November – to maintain healthy green leaf cover, said Ms Chambers.

“For late-lifted crops, we would advise putting on a second spray as rust is probably the main disease and it can reduce the leaf canopy considerably if it is not controlled.”

However, backward beet crops should be monitored and only sprayed if powdery mildew or rust can be found, she noted. “Spraying crops that are still small might have a negative effect on yield.”

Fungicides that offer effective control of powdery mildew, brown rust and cercospora include Escolta (cyproconazole + trifloxystrobin), Spyrale (difenoconazole + fenpropidin) and Opera (epoxiconazole + pyraclostrobin).

Researchers at Broom’s Barn are currently halfway through a four-year BBRO fungicide project looking at variety and yield responses to a one- and two-spray programme of Escolta.

Varieties in the trial included Bobcat, Bullfinch and Goya, and all three showed the best responses to two-spray programmes.

“Although Escolta was used in the trials, we would expect similar results from other fungicide products,” added Ms Chambers.

This season, Rosalinda will replace Goya in the trials to reflect changes in varieties grown commercially.

Two-stage crop

AICC agronomist Martin Lainsbury said: “The early drilled crops are some of the best I have seen in two decades in the industry and growers will need to get fungicides on early to protect the yield.

“However, some of the plants on the later drilled crops are still quite small. They didn’t germinate for a long time until we had some moisture late in June and therefore don’t have the same yield potential.”

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