Climate change-boosted disease could endanger China’s food supply

Wheat ear infected with Fusarium ear blight (FEB), giving the ear a pinkish color. The disease could be set to increase in countries like China and the UK with climate change, Bruce Fitt and his teammates have found, suggesting resistant varieties should be developed. Photo credit: CIMMYT.

Wheat ear infected with Fusarium ear blight (FEB), giving the ear a pinkish color. The disease could be set to increase in countries like China and the UK with climate change, Bruce Fitt and his teammates have found, suggesting resistant varieties should be developed. Photo credit: CIMMYT.

As the planet warms, China’s wheat crops will be threatened by more frequent epidemics of ‘fusarium ear blight’ (FEB), scientists in the UK and China have projected. Bruce Fitt from the University of Hertfordshire in Hatfield, UK, and his teammates forecast levels of the disease in the Anhui and Hubei provinces from 2021-2050. Whereas in the worst affected regions in 2001-2010 around one-sixth of all ears were infected, this was the lowest disease level the researchers found in their future scenario. In the worst-hit areas, FEB infected more than a third of all ears. “This has implications for crop breeding because it takes 10-15 years to breed a new cultivar,” Bruce told me. “If you know the disease is going to become more important then you need to get on and start breeding now rather than waiting until the disease hits you.”

Today, over a billion people don’t have enough to eat, and further population growth and climate change are set to put the world’s food supplies under even greater strain. To help ease that pressure, Bruce and other scientists are working to understand and help improve control of crop diseases like FEB. While some crop diseases will worsen in the future, not all will, he stressed. “For example, you might have a disease that is spread by rainsplash in summer and then it’s predicted that there will be far less rainfall in summer,” he explained. “Then you would expect that with climate change the importance of that disease would diminish.” If governments, farmers and seed suppliers know which diseases are likely to get worse, they can prioritise developing strategies to contol them, like breeding disease resistant varieties.

To make useful forecasts for which diseases will worsen, scientists build models that include weather data, how crops grow and how the disease pathogen spreads through the crop. “In this particular instance the wheat is susceptible only at flowering,” Bruce said. “It may be in flower for a few days. If it doesn’t get the pathogen inoculum and the right weather conditions at that time it will not get the disease.” Climate change can both alter flowering times and the chances of warm, wet weather that make infection more likely. When wheat gets infected, even if it can be harvested it is more likely to contain poisonous mycotoxins. “If it’s full of mycotoxins then it can’t be eaten by man or beast, so it’s just wasted,” Bruce added. Read the rest of this entry »

Mild winters raise risk of flu epidemics

Arizona State University mathematician Sherry Towers has found links between a warm winters with little flu to epidemics the following year. Credit: Arizona State University

Arizona State University mathematician Sherry Towers has found links between a warm winters with little flu to epidemics the following year. Credit: Arizona State University

In 2012/13 the US flu season started especially early for two strains for the first time since the government started tracking it in 1997. Sherry Towers at Arizona State University has put this down to the unusually warm winter the country saw in 2011/2012, after showing such a link can be seen in previous years. She hopes that her findings can help health services prepare as winters get yet milder with continuing climate change.

“Until now, it had not been noticed that the dynamics of the current season depend not only on the temperature of the current season and vaccine match, but also on what had occurred the year before,” Sherry told me. “If there has been a mild flu season during a mild winter, public health authorities know several months in advance that a severe season with early onset is much more likely to occur the next season. This allows them to expedite the manufacture and distribution of vaccines to the population.”

As a mathematician looking at how climate affects the spread of infectious diseases, Sherry follows influenza data collected by the US Centres for Disease Control (CDC) closely. The CDC tracks the various influenza virus types in circulation. These include letter and number combinations you might have heard, like H1N1 and H3N2, which together are classed as influenza A, plus the single type of influenza B virus. Scientists had previously shown that high temperatures reduce transmission of the virus, which alone would make mild flu seasons more common in warm winters. Though this suggests less of a threat from flu in a warmer world, this season’s data made her wonder if there could be a downside.

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