Viruses in cereals and oilseed rape

Some aphid species transmit yield-robbing viruses to cereals (BYDV) and oilseed rape (TuYV). Find out about the key species, virus symptoms and infection-risk management.

In both cereals and oilseeds, the key period for virus transmission by aphids is in the autumn.

Symptoms typically appear in spring and, in extreme situations, plants can die.

Many factors influence the extent of yield losses, for example:

• Earlier-sown winter crops and late-sown spring crops tend to be at a higher risk, due to the timing of aphid migrations
• Risk is heightened in all crops by mild conditions in autumn and winter, which encourage aphid flight, reproduction and movement within the crop

Although various species of cereal aphid transmit BYDV, bird cherry-oat aphid and grain aphid are the principal vectors.

Bird cherry-oat aphid is the most significant virus vector, partly due to the relatively high numbers that fly during autumn.

Grain aphids tend to be most problematic in crops that are sown very early or where there is poor green-bridge management.

Decision support tools can indicate high-risk periods and guide management interventions.

The main vector of TuYV in oilseed rape is the peach–potato aphid. It transmits the virus as it feeds on the crop during the autumn. As this aphid is resistant to a number of active ingredients, management relies heavily on integrated methods that reduce risk and target control.

Some soilborne vectors, not aphids, also transmit cereal mosaic viruses.

Wheat dwarf virus (WDV) is spread by a relatively new leafhopper species in the UK.