21 November 1997

First UKbeet low sugar disease

BLACKENED sugar beet crops in North Norfolk are likely to be the first recorded examples of low sugar disease in the UK.

Mike Asher, of IACR-Brooms Barn, reckons up to half the plants have been affected in some fields in the area. "Young leaves produced from the crown started to die from midsummer onwards, eventually turning black."

Older leaves then turned brown and died. Samples taken from the fields show sugar contents 1.3-3.2% lower in affected areas. Amino-N levels were doubled.

"Symptoms resemble boron deficiency. We cannot rule that out yet, though the fact we have found low sugars suggests it is not."

Detailed pictures of affected crops have been sent to France, where low sugar disease is more common, for identification.

The disease is caused by a mycoplasma organism spread by leaf hoppers. A late insecticide may prevent disease spread, though Dr Asher suspects that may only be needed in a hot summer, when leaf hoppers are most active.