Barley Yellow Dwarf Virus

The main source of the virus is grass or volunteer cereals. The virus is transmitted by aphids, particularly the bird cherry virus and the grain aphid. Aphids can colonise crops by walking onto germinating cereals from grassy stubble and volunteers. Aphids can also fly into crops and these aphids could be on the wing from August through to late-October depending on the season. Severe infections can also occur where cereals are grown after grass and where the grass has been ploughed immediately prior to sowing.

Controlling the aphid vectors is the key to minimising BYDV. The best way of managing the "green-bridge" from one crop to another is to kill off any aphid host plants before sowing. Ideally, stubble from the previous crop should be desiccated with a herbicide, ploughed in 7-10 days later and left for another 2 weeks before sowing the next crop. Alternatively, stubble can be ploughed in and sowing delayed for 4 weeks. Both these approaches reduce the threat from walking aphids by killing off their host plants that could keep the aphids ticking over. Crops should be checked regularly as soon as they begin to emerge for the presence of aphids, and an aphicide treatment applied if aphids are being found.