Phoma on the rise
PHOMA levels in oilseed rape rocketed last week. Growers should spray affected crops at the first chance to prevent yield loss and lodging next summer, says ADAS.
At Boxworth, Cambs, mild weather saw the disease rise from 28% of plants infected to 70% in the seven days to Monday. Uncontrolled phoma would cause moderate to severe stem cankers next spring and yield loss of 0.7t/ha (5.5cwt/acre). Similar increases are expected as far north as the Humber.
Backward crops with spotting should be protected first.
, using an eradicant such as difenconazole, or flusilazole (FW Oct 9).