AN unexpected side-effect of rising carbon dioxide levels will be more severe outbreaks of viruses in broadacre cereal crops.
These findings come out of world-first research in Victoria as part of the Australian Grains Free Air Carbon Enrichment (AGFACE) program, where crops are grown in an environment simulating the heightened levels of carbon dioxide (CO2) in the atmosphere projected by climate change experts.
Previously, AGFACE research has delivered some good news to farmers, such as the face high CO2 levels will boost crop plant growth and potentially yield.
However, work has also found higher CO2 levels can also raise the risk of barley yellow dwarf virus (BYDV) by more than a third.
BYDV is spread by aphids and is one of the most common plant viruses globally affecting cereal crops.
It can cause yield losses of up to 50 per cent in severe cases.
Horsham-based researcher Piotr Trebicki has led a Victorian Government team to undertake the work on BYDV and CO2.
Dr Trebicki, from the Victorian Government’s biosciences research division, said the study provides the first measurable evidence that the BYDV virus concentration increases in plants grown under elevated CO2 levels.
“Atmospheric CO2 levels are now at 400 parts per million but are predicted to increase to around 600 parts per million by 2050,” Dr Trebicki said.
“Results from the research showed that BYDV concentration increased 36.8pc in leaves of wheat grown under 2050 CO2 conditions compared to those at ambient levels.
“Plant height, tiller number, leaf area and biomass were generally higher in plants exposed to higher CO2 levels but increased growth did not explain the increase in BYDV infestation in these plants.
“High virus concentration in plants has been shown to significantly reduce plant yield.
“It also causes earlier and more pronounced symptoms increasing the chance of insects spreading the virus.
“Collectively these factors could negatively affect food production in both Australia and the rest of the world under future conditions,” Dr Trebicki said.
He said although the positive and negative impacts of CO2 on plants were well documented, little was known about interactions with pests and diseases.
“If disease severity increases under future environmental conditions, then it becomes imperative to understand the impacts of diseases on crop production in order to minimise crop losses and maximise food production.”