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: How Potatoes Conquered the World

It took centuries for the spud to travel from the New World to the Old and back again

The Wall Street Journal, November 15, 2018

At the first Thanksgiving dinner, eaten by the Wampanoag Indians and the Pilgrims in 1621, the menu was rather different from what’s served today. For one thing, the pumpkin was roasted, not made into a pie. And there definitely wasn’t a side dish of mashed potatoes.

In fact, the first hundred Thanksgivings were spud-free, since potatoes weren’t grown in North America until 1719, when Scotch-Irish settlers began planting them in New Hampshire. Mashed potatoes were an even later invention. The first recorded recipe for the dish appeared in 1747, in Hannah Glasse’s splendidly titled “The Art of Cookery Made Plain and Easy, Which Far Exceeds Any Thing of the Kind yet Published.”

By then, the potato had been known in Europe for a full two centuries. It was first introduced by the Spanish conquerors of Peru, where the Incas had revered the potato and even invented a natural way of freeze-drying it for storage. Nevertheless, despite its nutritional value and ease of growing, the potato didn’t catch on in Europe. It wasn’t merely foreign and ugly-looking; to wheat-growing farmers it seemed unnatural—possibly even un-Christian, since there is no mention of the potato in the Bible. Outside of Spain, it was generally grown for animal feed.

The change in the potato’s fortunes was largely due to the efforts of a Frenchman named Antoine-Augustin Parmentier (1737-1813). During the Seven Years’ War, he was taken prisoner by the Prussians and forced to live on a diet of potatoes. To his surprise, he stayed relatively healthy. Convinced he had found a solution to famine, Parmentier dedicated his life after the war to popularizing the potato’s nutritional benefits. He even persuaded Marie-Antoinette to wear potato flowers in her hair.

Among the converts to his message were the economist Adam Smith, who realized the potato’s economic potential as a staple food for workers, and Thomas Jefferson, then the U.S. Ambassador to France, who was keen for his new nation to eat well in all senses of the word. Jefferson is credited with introducing Americans to french fries at a White House dinner in 1802.

As Smith predicted, the potato became the fuel for the Industrial Revolution. A study published in 2011 by Nathan Nunn and Nancy Qian in the Quarterly Journal of Economics estimates that up to a quarter of the world’s population growth from 1700 to 1900 can be attributed solely to the introduction of the potato. As Louisa May Alcott observed in “Little Men,” in 1871, “Money is the root of all evil, and yet it is such a useful root that we cannot get on without it any more than we can without potatoes.”

In 1887, two Americans, Jacob Fitzgerald and William H. Silver, patented the first potato ricer, which forced a cooked potato through a cast iron sieve, ending the scourge of lumpy mash. Still, the holy grail of “quick and easy” mashed potatoes remained elusive until the late 1950s. Using the flakes produced by the potato ricer and a new freeze drying method, U.S. government scientists perfected instant mashed potatoes, which only requires the simple step of adding hot water or milk to the mix. The days of peeling, boiling and mashing were now optional, and for millions of cooks, Thanksgiving became a little easier. And that’s something to be thankful for.

For the Wall Street Journal