Warmer and wetter weather has been linked to higher rates of infection in an analysis of plant virus outbreaks across the world from 1984 to 2019.
Warmer and wetter weather has increased the spread of plant viruses in the past few decades, and climate change is expected to result in more outbreaks in the future.
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| A tobacco plant infected with tobacco mosaic virus Nigel Cattlin /Alamy |
Erin Mordecai at Stanford University in California and her colleagues analysed the spread of viral pathogens in 5380 wild and agricultural plant populations across six continents from 1984 to 2019. They used data from dozens of previous studies that mainly focused on plant populations where some disease is typically present.
By analysing local temperature and rainfall data during past disease outbreaks, the team found that wild plants living in historically cold areas – with an average temperature of 3°C from 1960 to 1990 – were more likely to catch viral diseases during periods of warmer weather over the following decades.
Among wild plants in historically cold regions, the incidence of viral disease was roughly 40 per cent at temperatures around 5°C. This increased to around 50 per cent when temperatures reached 15°C and around 70 per cent when temperatures exceeded 30°C. Similar effects were seen among agricultural plants.
Heavier rainfall was also linked to increased spread of viruses among wild plant populations, especially those in historically wet areas, with 3.9 millimetres of daily rainfall on average. In these areas, a rise to 6 millimetres per day increased the risk of viral disease by roughly 10 per cent.
In contrast, wetter conditions had little effect on disease risk among agricultural crops, probably because farmers take measures to counteract overwatering of their fields, says André Velásquez at Western Carolina University in North Carolina, who wasn’t involved in the study.
The study highlights how weather extremes, which are predicted to become more common with climate change, will make disease outbreaks more likely, says Velásquez.
“If actions are not taken to mitigate the danger of climate change, worldwide food production chains might be affected, the effect being felt more dramatically for farmers with limited resources,” he says.
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