Organic Chemistry Helps Feed the World
The world’s leading agricultural fungicide, azoxystrobin, was developed in the UK by organic chemists. It is now used to protect over 120 different crops, including potatoes, cotton, fruit and wheat, from fungal diseases. Its structure was inspired by a naturally occurring compound found in a fungus.
Why do we need fungicides?
Azoxystrobin is used in over 100 countries to protect many staple crops from a broad range of fungal infections. It is selective, stable, easy to apply, and safe for consumers and the environment. Azoxystrobin has a novel mode of action, which means that it is effective even on crops which have evolved resistance to other fungicides. Global sales of azoxystrobin are over $1 billion.
Without effective crop protection chemicals, current crop yields would fall by around 40%. Organic chemists play a vital role in research and development of safe, effective crop protection chemicals, and azoxystrobin is just one example of a hugely successful research programme.
Synthesising a novel fungicide
The organic chemists who discovered azoxystrobin began with an interest in a natural fungicide, strobilurin A, which occurs in various fungi which grow in rotting wood. On investigation, they found that strobilurin was unsuitable for use as a fungicide, because its activity is weak and it is unstable in sunlight.
So the chemists began to synthesise compounds with similar structures to strobilurin A which had broad fungicidal activity, could be easily applied to crops, and were safe for the environment. By synthesising hundreds of compounds, chemists were able to fine tune the fungicidal activity and physical properties until they discovered the most effective compound – azoxystrobin.
Figure 1 shows the differences between the structures of strobilurin A and azoxystrobin. The group which gives strobilurin its fungicidal activity is retained in azoxystrobin, but several other functional groups have been replaced or added to improve the properties of the chemical.
It takes on average 9 years and £150 million for a fungicide like azoxystrobin to be developed and registered to use. As the global population continues to grow to an estimated 9 billion in 2050, there will be many more opportunities for novel research like that which led to the discovery of azoxystrobin.
“A reliable supply of food for the growing world population is critically important. Agricultural fungicides, of which azoxystrobin is the leading example, make a key contribution to the yield and quality of numerous crops.”
John Clough, Organic Chemist
Also of interest
Ian Le Guillou finds out how the success of the synthetic organic fungicide azoxystrobin showcases the importance of organic chemistry to global food production
26 September 2012, London. Dr John Clough's lecture outlines the chemistry that led to the discovery of the world's best-selling fungicide, azoxystrobin.
Significantly and sustainably increase agricultural productivity to provide food, feed, fibre and fuel
By 2030, the world’s population is expected to rise to over eight billion - the need for safe and environmentally friendly crop protection chemical has never been greater
Scientists at Syngenta explain how crop protection products work in these video resources for 11 to 18 year olds
An in depth case study for 16 to 18 year olds looking at the development of azoxystrobin by Zeneca
Contact and Further Information
Dr Anne Horan
Programme Manager, Life Sciences
Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge, CB4 0WF
Tel: 01223 432699