PHOMA RISK level has been increased to red alert, as mild conditions favour spore release, according to latest crop monitoring results.

The latest alert follows warnings three weeks ago that aerial phoma spores had being discovered in ADAS monitoring traps in Yorkshire 4 to 6 weeks earlier than normal.

The Syngenta Phoma Advance Warning System (SPAWS) highlighted the red ‘high risk‘ alert on Friday (Oct 1) and recommends growers monitor crops regularly and act on signs quickly.

The very early spore release recorded this year is particularly serious as oilseed rape plants are still relatively small and infection can rapidly spread down the stems, said Syngenta‘s Beth Hall.

Syngenta recommends seven key actions growers should take to help control phoma:

  • Monitor crops on a weekly basis
  • Prioritise susceptible varieties
  • Fungicide applications should be made at lower threshold of 10% of plants infected
  • Cultivate remaining OSR stubbles to reduce spore spread
  • Apply 0.25l/ ha Plover if 10% threshold reached
  • Avoid complex fungicide mixtures on small or stressed crops
  • Look out for SPAWS warnings