The first instances of powdery mildew in sugar beet have been reported in crops near the south Suffolk and north Norfolk coasts, according to the British Beet Research Organisation (BBRO).

Mildew may therefore be a risk on moisture retentive soils, or those that have received recent rain, it said.

The BBRO outlines some key advice to growers:

  • Make fungicide applications as close to the end of the month as possible to ensure disease control and greening through to September
  • Avoid spraying wilted crops as chemical uptake may be less effective
  • Take into account variety susceptibility and anticipated harvest date before choosing products
  • Use triazoles (alone or in a mix) to provide the greening effect
  • The most cost-effective options include:

Variety  Early harvest  Late harvest
Resistant to powdery mildew Punch (0.625 litres/ha) [£15/ha]
or
Fortress (0.1 litres/ha) + Cabaret (0.125 litres/ha) [£12/ha]
Fortress (0.1l/ha) + Cabaret (0.125l/ha)
Susceptible to powdery mildew Punch (0.625 litres/ha) [£15/ha]
or
Fortress (0.2 litres/ha) + Cabaret (0.125 litres/ha) [£19/ha]

Fortress (0.2 litres/ha) + Cabaret (0.125 litres/ha) [£12/ha]
or
Punch (0.625) followed by Cabaret (0.25 litres/ha) [£26/ha]

Note: Punch (carbendazim + flusilazole), Fortress (quinoxyfen), Cabaret (cyproconazole)

For more information see BBRO Advisory Bulletin 21 at www.uksugarbeet.co.uk