27 September 1996

Plan to spray in winter rape

DONT delay disease control in winter rape and choose fungicides with care, warns Du Pont.

"Market research shows farmers are often spraying too late," says the firms Andy Selley.

Trials with NIAB highlight the value of an Oct/Feb split for phoma stem canker control. Using 0.4 litres/ha (0.3pt/acre) of Punch C (carbendazim + flusilazole) at each timing on Synergy gave more than 0.5t/ha (4cwt/acre) extra. "Thats a net return of over £75/ha," he says.

Delay disadvantages

Delaying the first spray until December cut the benefit by about £55/ha (£22/acre). HGCA-funded work shows similar results for light leaf spot, he says.

Growers should also avoid using leftover cereal fungicide, adds Mr Selley. Nottingham University trials using half rates show flusilazole offering better control than either difenoconazole (as in Plover) or prochloraz (Sportak), he says.