Barley yellow dwarf virus
The yellow dwarf virus of cereals has been divided into two groups, barley yellow dwarf virus (BYDV) and cereal yellow dwarf virus (CYDV). Yellow Dwarf Virus is spread to cereal crops from infected perennial grasses by cereal aphid vectors. Cereal aphids pick up the virus while feeding from vascular tissues of infected plants. Once contracted, BYDV is carried on the aphid's salivary glands for their whole life and the virus is then transmitted by feeding on healthy plants. However they need to probe right into the vascular tissue of the phloem to infect the plant, which requires deep and relatively long periods of feeding. During autumn and early winter, flights of aphids from infected grasses establish colonies in crops. Once established, infected aphids move to healthy plants and start feeding - spreading BYDV as they go. Infection occurs in the vascular tissues in the cereal plant - restricting movement of water and nutrients up the stem.
How BYDV affects plants
Infection occurs in the vascular tissues in the cereal plant - restricting movement of water and nutrients up the stem. Plants infected prior to mid-tillering are stunted. Yield can be decreased by up to 50%. The percentage of shriveled grain increases with BYDV and means quality is also affected. However with late infection, post-tillering, yield is largely unaffected.
- BYDV symptoms take 3 weeks to appear and can easily be confused with nutrient deficiencies
- When infection occurs early in the life of the crop (before the end of tillering), stunting can occur and is sometimes quite severe
- BYDV infection usually causes circular patches of yellowing or reddening on plants, and can be distinguished by the pattern of spread in the crop
- Treat the seed with a recommended seed treatment (Guardian)
- Choose resistant varieties
- Time of sowing