Perennial and Italian ryegrasses, the types Spangenberg and his team have genetically modified, are sown for lawns and pasture around the world and account for 70 per cent of grass seed sold in the European Union. Ryegrass is the main cause of hay fever in Europe and Australia, although ragweed triggers more hay fever attacks in the US. Hypoallergenic ryegrass lawns and pasture could conceivably help reduce the incidence of hay fever, says allergy expert Tim O'Meara, of the Woolcock Institute of Medical Research in Sydney.