Kudzu, a leafy vine that is native to Japan and China, was introduced to the USA during the late 19th century, where it was cultivated extensively in order to control soil erosion. But due to its ability to fix nitrogen in the soil, it grows extremely rapidly – around three times as fast as other vegetation – and is now a serious pest.

The plant produces the chemicals isoprene and nitric oxide, which combine with atmospheric nitrogen to produce ozone. Although it acts as a shield against UV rays in the upper atmosphere, at ground level, ozone is a pollutant that causes significant health problems in humans – including lung damage that can lead to asthma and lung cancer – and can hinder growth in plants, including crops.

‘We found that this chemical reaction caused by kudzu leads to about a 50 per cent increase in the number of days each year in which ozone levels exceed what the Environmental Protection Agency deems to be unhealthy,’ said Manuel Lerdau of the University of Virginia, co-author of the study published in the Proceedings of the National Academy of Sciences.

July 2010