Plant protection products should act on specific targets, if possible affecting only certain pests and diseases. Agricultural crops must not be harmed, and the use of these products must be safe for both humans and the environment. This places enormous demands on industrial scientists. Researching new products and methods for protecting plants is very time-consuming and expensive. It takes 12 years, on average, for a new active ingredient to be approved for the market. Development costs exceed 280 million USD.

Observe
Observing natural products and processes is an important source of inspiration for scientists. The recognition that certain plants and living things do not thrive when in close proximity has led to the development of numerous crop protection products. In 1977, the Californian chemist Reed Gray discovered something interesting in his garden. He noticed that almost no weeds were growing underneath his crimson bottlebrush plants (Callistemon citrinus), a phenomenon that could not be explained simply by the fact that the area underneath was in the shade.

Understand
Gray took soil samples and examined them in his laboratory. It turned out that bottlebrush plants produce a substance that inhibits the growth of other plants. Chemical analyses identified this substance as leptospermone; this blocks the production of carotenoids, which provide protection against UV light, in other plants. In the absence of carotenoids, plants are bleached by the sunlight and die. A new means of controlling weeds had been discovered.

Improve
But there was a catch. Extremely large quantities of leptospermone are needed to protect plants – up to 9 kilograms per hectare. Producing and marketing the necessary amounts of this substance would require the cultivation of huge fields of bottlebrush. Instead, scientists took inspiration from the chemical structure of leptospermone, then worked tirelessly to synthesize similar compounds displaying the desired characteristics. Eleven years after Reed Gray first isolated leptospermone, researchers at Syngenta were able to synthesize the active ingredient mesotrione, which has a similar structure. It was between 50 and 100 times as effective as leptospermone, and could be used safely. This crop protection product, inspired by the Callistemon citrinus plant, was introduced to the U.S. and European markets in 2001, and has been continually improved since that time.