Historically Speaking: The Search for Better Weapons Against Pests

From sulfur to DDT, farmers have spent millennia looking for ways to stop crop-destroying insects.

The Wall Street Journal

April 20, 2023

The scientific breakthroughs of the 17th century, such as the compound microscope, made the natural world more intelligible and therefore controllable. By the 18th century, a farmer’s arsenal included nicotine, mercury and arsenic-based insecticides.

The Mesopotamians realized the necessity for pest control as early as 2500 B.C.E. They were fortunate to have access to elemental sulfur, which they made into a powder or burned as fumes to kill mites and insects. Elsewhere, farmers experimented with biological weaponry. The predatory ant Oecophylla smaragdina feasts on the caterpillars and boring beetles that destroy citrus trees. Farmers in ancient China learned to plant colonies next to their orange groves and tie ropes between branches, enabling the ants to spread easily from tree to tree.

The scientific breakthroughs of the 17th century, such as the compound microscope, made the natural world more intelligible and therefore controllable. By the 18th century, a farmer’s arsenal included nicotine, mercury and arsenic-based insecticides.

Pierre Marie Alexis Millardet, Bordeaux

Illustration: Thomas Fuchs

But the causes of fungal blight remained a mystery. In 1843, the pathogen behind potato late blight, Phytophthora infestans, jumped from South America to New York and Philadelphia, and then crossed the Atlantic. Ireland had all the ingredients for an agricultural catastrophe: cool, wet winters, water-retaining clay soil, and reliance on a single potato variety as a food staple, combined with the custom of storing old and new potato crops together. Four years of heavily infected harvests, made worse by the British government’s failed response to the emergency, led to more than a million deaths.

In the 1880s, French vineyards were under attack from a different blight, Uncinula necator. By a happy coincidence, Pierre Marie Alexis Millardet, a botany professor at the University of Bordeaux, noticed that some grape vines growing next to a country road were free of the powdery mildew, while those further away were riddled with it. The owner explained that he had doused the roadside vines with a mix of copper sulfate and lime to deter casual picking. Armed with this knowledge, in 1885 Millardet perfected the Bordeaux mixture, the first preventive fungicide, which is still used today.

At the same time, an American entomologist named Albert Koebele was experimenting with biological pest controls. Citrus trees were once again under attack, only now it was the cottony cushion scale insect. Koebele went to Australia in 1888 and brought back its best-known predator, the vedalia beetle, thereby saving California’s citrus industry.

In 1936, the development of DDT, the first synthetic insecticide, was hailed as a miracle of science, offering the first real defense against malaria and other insect-borne diseases. But it was later discovered to be toxic to animals and humans, and it killed insects indiscriminately. Among its many victims was the vedalia beetle, which led to a resurgence of cottony cushion scale. Ultimately, the Environment Protection Agency banned DDT’s use in 1972.

The race to invent environmentally safe alternatives is ramping up, but so are the pests. After a wet winter on the West Coast and a warm one in the East, experts are predicting great swarms of bloodsucking insects. Help!

Historically Speaking: Democracy Helped Seed National Parks

Green spaces and nature preserves have long existed, but the idea of protecting natural wonders for human enjoyment has American roots.

The Wall Street Journal

March 3, 2022

Yellowstone, the world’s oldest national park, turned 150 this month. The anniversary of its founding is a timely reminder that democracy isn’t just a political system but a way of life. The Transcendentalist writer Henry David Thoreau was one of the earliest Americans to link democratic values with national parks. Writing in 1858 he declared that having “renounced the king’s authority” over their land, Americans should use their hard-won freedom to create national preserves for “inspiration and our own true re-creation.”

There had been nature reserves, royal hunting grounds, pleasure gardens and parks long before Yellowstone, of course. The origins of green spaces can be traced to ancient Egypt’s temple gardens. Hyde Park, which King Charles I opened to Londoners in 1637, led the way for public parks. In the 3rd century B.C., King Devanampiya Tissa of Sri Lanka created the Mihintale nature reserve as a wildlife sanctuary, prefiguring by more than 2,000 years the likely first modern nature reserve, which the English naturalist Charles Waterton built on his estate in Yorkshire in the 1820s.

The Grand Canyon of the Yellowstone River, Yellowstone National Park, 1920. GAMMA-KEYSTONE/GETTY IMAGES

The 18th century saw a flowering of interest in man’s relationship with nature, and these ideas encouraged better management of the land. The English scientist Stephen Hale demonstrated the correlation between tree coverage and rainfall, leading a British MP named Soame Jenyns to convince Parliament to found the Tobago Main Ridge Forest Reserve in 1776. The protection of the Caribbean colony’s largest forest was a watershed moment in the history of conservation. Highly motivated individuals soon started conservation projects in multiple countries.

As stewards of their newly independent nation, Americans regarded their country’s natural wonders as places to be protected for the people rather than from them. (Niagara Falls, already marred by development when Alexis de Tocqueville visited in 1831, served as a cautionary example of legislative failure.) The first attempt to create a public nature reserve was at the state level: In 1864 President Abraham Lincoln signed the Yosemite Valley Grant Act, giving the land to California “upon the express conditions that the premises shall be held for public use, resort, and recreation.” But the initiative lacked any real oversight.

Many groups pushed for a federal system of national parks. Among them were the Transcendentalists, environmentalists and landscape painters such as George Catlin, Thomas Cole and Albert Bierstadt, but the ultimate credit belongs to the geologist Ferdinand Hayden, who surveyed Yellowstone in 1871. The mass acclaim following his expedition finally convinced Congress to turn Yellowstone into a national park.

Unfortunately, successive administrations failed to provide sufficient funds for its upkeep, and Yellowstone suffered years of illegal poaching and exploitation. In desperation, the federal government sent the U.S. Army in to take control of the park in 1886. The idea proved to be an inspired one. The military was such a conscientious custodian that its management style became the model for the newly created National Park Service in 1916.

The NPS currently oversees 63 National Parks. But the ethos hasn’t changed since the Yellowstone Act of 1872 set aside 2 million pristine acres “for the benefit and enjoyment of the people.” These words are now engraved above the north entrance to the park, an advertisement, as the novelist and environmentalist Wallace Stegner once wrote, that national parks are “absolutely American, absolutely democratic.”