THE NATURAL SCIENCES EMERGING in Europe and Britain during the nineteenth century took on a different trajectory to that in the colonies. Settlement and expansion of growing populations had brought massive disruptions and changes to ‘new’ environments. Whereas the old world had centuries of established farming practice and land utilisation to support human needs, the territories of the new world were experiencing a tsunami of change. With this came new problems and new pests, as well as freshly qualified individuals equipped to respond to these problems. They called themselves scientists, as opposed to natural philosophers (a term Darwin and many of his generation preferred). In response to a taunt by the poet Samuel Taylor Coleridge (at a meeting of The British Association for the Advancement of Science in 1833) that the term ‘natural philosopher’ needed to go, because philosophers advanced humanity through thoughts rather than actions, William Whewell (1794–1866) coined the phrase ‘scientist’ as an analogy with artist. Whewell was a polymath Cambridge scholar who excelled in both mathematics and poetry. He was also a wordsmith, generating the terms ‘physicist’, ‘linguistics’ and ‘astigmatism’, among others. Spawned from the humanities, the word and work of scientists has come to dominate our lives, whatever we choose to call its practitioners.

Following the American Civil War in the 1860s, agriculture expanded in North America on a huge scale. In 1869, there were just over two million farms in the United States. Forty years later, there were over 575 million farms, and land under cultivation had more than doubled to over 840 million acres. Most of this development was in the Midwest and West where millions of acres of tallgrass prairie land were brought under the plough – often with disastrous ecological consequences.

As agriculture grew in the post-reconstruction economy, productivity at first expanded. The virgin land was so productive that North America's farmers became victims of their own success as produce prices dropped. But land cannot be farmed without replenishing the soil, and poor soil produces poor crops, which in turn are more susceptible to attack from disease and insects. Monocultures (particularly cotton) expanded, and the insects preying on crops also increased in variety and number.