Turnip yellows virus alert

Turnip yellows virus (TuYV) is Australia's most economically damaging virus for canola and is primarily spread by green peach aphid (GPA).

Crops are most vulnerable during early growth stages, making prevention and early intervention critical.

If TuYV spreads to more than 50% of plants prior to stem elongation, applying insecticides is unlikely to be economically effective.

Seasonal conditions have been favourable for aphids in early 2026, with high rainfall and a strong green bridge driving population build-up.

In early April, a SARDI pathology team visited a forage brassica site in southeast South Australia as part of the GRDC national investment “Effective virus management in grain crops” (DAW2305-003RTX), where high aphid populations were observed. The brassica showed typical purpling of leaves associated with turnip yellows virus in the emerging crop. Testing along a transect of the paddock found an extremely high proportion of TuYV infection, nearing 100%.

Aphid populations have since declined with cooler weather. However, highly infected fields and surrounding weeds may act as reservoirs for early TuYV infection in canola – see Manage turnip yellows virus in canola.

Please contact Dr Nicole Thompson (email: Nicole.Thompson@sa.gov.au) to report any observations of TuYV in emerging canola, or other virus-like symptoms in your crops.