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: Beware the Red Tide

Massive algae blooms that devastate ocean life have been recorded since antiquity—and they are getting worse.

In H.G. Wells’s 1898 novel “The War of the Worlds,” the invading Martians bring with them a noxious red weed that suffocates the land and poisons the water. Fortunately, it dies off at the end of the novel, killed by good old British bacteria.

Real life isn’t so tidy. Currently, there is no force, biological or otherwise, capable of stopping the algae blooms that are attacking coastal waters around the world with frightening regularity, turning thousands of square miles into odoriferous graveyards of dead and rotting fish. In the U.S., one of the chief culprits is the Karenia brevis algae, a common marine microorganism that blooms when exposed to sunlight, warm water and phosphorus or nitrates. The result is a toxic sludge known as a red tide, which depletes the oxygen in the water, poisons shellfish and emits a foul vapor strong enough to irritate the lungs.

The red tide isn’t a new phenomenon, though its frequency and severity have certainly gotten worse thanks to pollution and rising water temperatures. There used to be decades between outbreaks, but since 1998 the Gulf Coast has suffered one every year.

The earliest description of a red tide may have come from Tacitus, the first-century Roman historian, in his “Annals”: “the Ocean had appeared blood-red and…the ebbing tide had left behind it what looked to be human corpses.” The Japanese recorded their first red tide catastrophe in 1234: An algae bloom in Osaka Bay invaded the Yodo River, a major waterway between Kyoto and Osaka, which led to mass deaths among humans and fish alike.

The earliest reliable accounts of red tide invasions in the Western Hemisphere come from 16th-century Spanish sailors in the Gulf of Mexico. The colorful explorer Álvar Núñez Cabeza de Vaca (ca. 1490-1560) almost lost his entire expedition to red tide poisoning while sailing in Apalachee Bay on the west coast of Florida in July 1528. Unaware that local Native American tribes avoided fishing in the area at that time of year, he allowed his men to gorge themselves on oysters. “The journey was difficult in the extreme,” he wrote afterward, “because neither the horses were sufficient to carry all the sick, nor did we know what remedy to seek because every day they languished.”

Red tides started appearing everywhere in the late 18th and early 19th centuries. Charles Darwin recorded seeing red-tinged water off the coast of Chile during his 1832 voyage on HMS Beagle. Scientists finally identified K. brevis as the culprit behind the outbreaks in 1946-47, but this was small comfort to Floridians, who were suffering the worst red tide invasion in U.S. history. It started in Naples and spread all the way to Sarasota, hanging around for 18 months, destroying the fishing industry and making life unbearable for residents. A 35-mile long stretch of sea was so thick with rotting fish carcasses that the government dispatched Navy warships to try to break up the mass. People compared the stench to poison gas.

The red tide invasion of 2017-18 was particularly terrible, lasting some 15 months and covering 145 miles of Floridian coastline. The loss to tourism alone neared $100 million. Things are looking better this summer, fortunately, but we need more than hope or luck to combat this plague; we need a weapon that hasn’t yet been invented.

Historically Speaking: How We Kept Cool Before Air Conditioning

Wind-catching towers and human-powered rotary fans were just some of the devices invented to fight the heat.

ILLUSTRATION: THOMAS FUCHS

What would we do without our air conditioning? Given the number of rolling blackouts and brownouts that happen across the U.S. each summer, that’s not exactly a rhetorical question.

Fortunately, our ancestors knew a thing or two about staying cool even without electricity. The ancient Egyptians developed the earliest known technique: Evaporative cooling involved hanging wet reeds in front of windows, so that the air cooled as the water evaporated.

The Romans, the greatest engineers of the ancient world, had more sophisticated methods. By 312 B.C. they were piping fresh water into Rome via underground pipes and aqueducts, enabling the rich to cool and heat their houses using cold water pipes embedded in the walls and hot water pipes under the floor.

Nor were the Romans alone in developing clever domestic architecture to provide relief in hot climes. In the Middle East, architects constructed buildings with “wind catchers”—tall, four-windowed towers that funneled cool breezes down to ground level and allowed hot air to escape. These had the advantage of working on their own, without human labor. The Chinese had started using rotary fans as early as the second century, but they required a dedicated army of slaves to keep them moving. The addition of hydraulic power during the Song era, 960-1279, alleviated but didn’t end the manpower issue.

There had been no significant improvements in air conditioning designs for almost a thousand years when, in 1734, British politicians turned to Dr. John Theophilus Desaguliers, a former assistant to Isaac Newton, and begged him to find a way of cooling the overheated House of Commons. Desaguliers designed a marvelous Rube Goldberg-like system that used all three traditional methods: wind towers, pipes and rotary fans. It actually worked, so long as there was someone to crank the handle at all times.

But the machinery wore out in the late 1760s, leaving politicians as hot and bothered as ever. In desperation, the House invited Benjamin Franklin and other leading scientists to design something new. Their final scheme turned out to be no better than Desaguliers’s and required not one but two men to keep the system working.

The real breakthrough occurred in 1841, after the British engineer David Boswell Reid figured out how to control room temperature using steam power. St. George’s Hall in Liverpool is widely considered to be the world’s first air-conditioned building.

Indeed, Reid is one of history’s unsung heroes. His system worked so well that he was invited to install his pipe and ventilation design in hospitals and public buildings around the world. He was working in the U.S. at the start of the Civil War and was appointed inspector of military hospitals. Unfortunately, he died suddenly in 1863, leaving his proposed improvements to gather dust.

The chief problem with Reid’s system was that steam power was about to be overtaken by electricity. When President James Garfield was shot by an assassin in the summer of 1881, naval engineers attempted to keep him cool by using electric fans to blow air over blocks of ice. Two decades later, Willis Haviland Carrier invented the first all-electric air conditioning unit. Architects and construction engineers have been designing around it ever since.

Fears for our power grid may be exaggerated, but it’s good to know that if the unthinkable were to happen and we lost our air conditioners, history can offer us some cool solutions.

Historically Speaking: Overrun by Alien Species

From Japanese knotweed to cane toads, humans have introduced invasive species to new environments with disastrous results

The Wall Street Journal, November 1, 2018

Ever since Neolithic people wandered the earth, inadvertently bringing the mouse along for the ride, humans have been responsible for introducing animal and plant species into new environments. But problems can arise when a non-native species encounters no barriers to population growth, allowing it to rampage unchecked through the new habitat, overwhelming the ecosystem. On more than one occasion, humans have transplanted a species for what seemed like good reasons, only to find out too late that the consequences were disastrous.

One of the most famous examples is celebrating its 150th anniversary this year: the introduction of Japanese knotweed to the U.S. A highly aggressive plant, it can grow 15 feet high and has roots that spread up to 45 feet. Knotweed had already been a hit in Europe because of its pretty little white flowers, and, yes, its miraculous indestructibility.

First mentioned in botanical articles in 1868, knotweed was brought to New York by the Hogg brothers, James and Thomas, eminent American horticulturalists and among the earliest collectors of Japanese plants. Thanks to their extensive contacts, knotweed found a home in arboretums, botanical gardens and even Central Park. Not content with importing one of world’s most invasive shrubs, the Hoggs also introduced Americans to the wonders of kudzu, a dense vine that can grow a foot a day.

Impressed by the vigor of kudzu, agriculturalists recommended using these plants to provide animal fodder and prevent soil erosion. In the 1930s, the government was even paying Southern farmers $8 per acre to plant kudzu. Today it is known as the “vine that ate the South,” because of the way it covers huge tracts of land in a green blanket of death. And Japanese knotweed is still spreading, colonizing entire habitats from Mississippi to Alaska, where only the Arctic tundra holds it back from world domination.

Knotweed has also reached Australia, a country that has been ground zero for the worst excesses of invasive species. In the 19th century, the British imported non-native animals such as rabbits, cats, goats, donkeys, pigs, foxes and camels, causing mass extinctions of Australia’s native mammal species. Australians are still paying the price; there are more rabbits in the country today than wombats, more camels than kangaroos.

Yet the lesson wasn’t learned. In the 1930s, scientists in both Australia and the U.S. decided to import the South American cane toad as a form of biowarfare against beetles that eat sugar cane. The experiment failed, and it turned out that the cane toad was poisonous to any predator that ate it. There’s also the matter of the 30,000 eggs it can lay at a time. Today, the cane toad can be found all over northern Australia and south Florida.

So is there anything we can do once an invasive species has taken up residence? The answer is yes, but it requires more than just fences, traps and pesticides; it means changing human incentives. Today, for instance, the voracious Indo-Pacific lionfish is gobbling up local fish in the west Atlantic, while the Asian carp threatens the ecosystem of the Great Lakes. There is only one solution: We must eat them, dear reader. These invasive fish can be grilled, fried or consumed as sashimi, and they taste delicious. Likewise, kudzu makes great salsa, and Japanese knotweed can be treated like rhubarb. Eat for America and save the environment.

WSJ Historically Speaking: The Lesson of the Last Passenger Pigeon

Photo: THOMAS FUCHS

Photo: THOMAS FUCHS

In April 1896, a flock of American passenger pigeons was discovered nesting in a forest outside Bowling Green, Ohio. Once the most ubiquitous bird in North America, the passenger pigeon had shrunk from countless billions to this single of flock of 250,000. News of the find was telegraphed across the country, drawing hundreds of visitors to the area.

By this time, the great bison—a powerful symbol of frontier America—had dwindled from a population of tens of millions to just a few hundred, all in zoos or reservations. Determined to prevent a similar fate for the passenger pigeon, several states had already enacted hunting bans. Seeing the birds gave conservationists hope that the restrictions were working.

Unfortunately, the visitors to Bowling Green weren’t bird watchers but hunters, and Ohio had no such protective laws. They killed the entire flock in a day. Afterward, the train taking the carcasses to sell in New York City derailed, leaving them to rot in a ravine. Eighteen years later, the lone survivor of the species—a female bird named Martha, after George Washington’s wife—died in a cage in the Cincinnati zoo.

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