17 July 1998

Italian job in autumn

SOW Italian ryegrass in autumn and take extra care with variety choice when growing a single variety to avoid disease.

Italian ryegrass varieties are more prone to disease than perennial varieties and it is more common to sow a single variety to reduce seed costs for a short term ley or catch crop, says NIABs Jim McVittie.

He explains that four varieties are particularly prone to brown rust in May when grown alone. These are Tribune, AberComo, Trajan and Exalta.

Sowing seed in autumn helps ensure swards last longer, because ryegrass mosaic virus, which builds up in the life of a sward, is active in June and July. When sown in September, the following spring yield can be higher because the disease has not had a chance to infect the sward, he adds.

Italian ryegrasses can also suffer from rhynchosporium, which is worst in wet areas, and mildew, which is more common in drier areas such as the east of England, so appropriate varieties for the site must be selected.