Graze hard to prevent rust
WARM autumn conditions have seen crown rust develop on grass swards, and to reduce risks these pastures should be grazed down hard.
According to New Zealand dairy consultant Paul Bird, working in the south-west for the British Grassland Society, grass with rust should not be carried over winter.
Graze infected swards down until the grass is fairly short to reduce the risk of crown rust again in spring, he says.
Staffordshire-based dairy consultant Ian Browne has seen the disease for the first time in the area. "Orange patches are visible in areas which have never had crown rust before, which is a worry for late grazers." He attributes its prevalence to the unusual weather this autumn with warm days and cooler nights creating ideal conditions for its spread.
GRAS technical adviser Robin Turner suggests that increased defoliation through more frequent cutting or grazing will help control its spread – as will a minimum application of 250kg/ha (200 units/acre) nitrogen. Incidence is linked with low N use. *