Ox Urine to Olive Oil: Fighting Garden Pests Like the Colonists

Diluted lime for plants, gardening — After diluting lime, Colonial Williamsburg gardener Wesley Greene pours it into watering cans for treating plants.

(Image credit: Wesley Greene)

Wesley Greene is garden historian for the Colonial Williamsburg Foundation. This article is adapted from one that originally appeared as "Snails, Flies and Caterpillars" in The Interpreter. Greene contributed this article to Live Science's Expert Voices: Op-Ed & Insights.

When humans first gathered food plants into a garden, they simultaneously created an ideal habitat for insects to feed, initiating a battle for sustenance that continues to this day. For the largest part of human history, the insects have had the upper hand.

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"There is none so dul of eye-sight (as I believe) who not thorowly perceiveth and seeth, how that the Garden riches be diversly annoyed, and harmed by divers creeping worms and beasts, as wel above as under the earth, and that through the same occasion, often procured to feeble and wast, and unlesse speedy remedies shall be exercised, that these in the end do fall down and perish." [Editor's note: original text spellings are used throughout this article.]

The remedy, of course, has been the problem. In his book, Hill recommends many of the same techniques that had been practiced for more than a thousand years at the time and that continued well into the 19th century. Plants were sprinkled with fig tree ashes, ox urine, olive oil and the soot of chimneys. Sulfur, lixivium of limewater (a solution of slaked lime) and assafætida (an evil-smelling latex from the roots of several species of Ferula plants) were sprayed on the leaves. Bundles of garlic, brimstone (sulfur), goat hooves and hart's horn were burned between the rows to ward off pests.

One of the first scientific investigations into spontaneous generation was conducted by the Italian physician, Francesco Redi, in 1668. It was generally believed that maggots arose spontaneously in rotting meat, but Redi postulated that the organisms actually arose from the eggs laid by flies. To test his hypothesis, Redi set meat out in a number of flasks, some open to the air, some sealed completely and others covered with gauze. The maggots appeared only in the open flasks, proving that the flies had to be able to reach the meat to lay their eggs.

The debate over spontaneous generation continued through the 18th century. In 1745, the English clergyman John Needham conducted what he claimed to be the experiment that definitively settled the debate. After the invention of the microscope, it was readily apparent that boiling killed microorganisms. So, in his experiment, Needham boiled chicken broth in a flask and then allowed the liquid to cool. Within a few days, microorganisms had formed a scum on the surface of the broth, proving the theory of spontaneous generation, Needham claimed.

Lazzaro Spallanzani, an Italian priest, was not convinced. In 1768, he proposed that the microorganisms had been introduced from the air. In his experiment, he boiled meat broth in one flask that was allowed to stand open and in another that was sealed. The open flask grew microorganisms; the sealed flask did not. Doubters argued that this only proved that spontaneous generation could not occur without air.

In 1859, the French Academy of Sciences solicited experiments to prove or disprove spontaneous generation. A young French chemist named Louis Pasteur created the experiment that finally lay to rest the theory of spontaneous generation (decades before he developed the rabies vaccine). In his experiment, as others had in the earlier tests, Pasteur boiled meat broth in a flask. But he modified the container by heating the neck of the flask and bending it into an S shape so that air could enter but airborne spores could not. The broth in the flask remained clear. In a definitive demonstration, he then tipped the broth into the lowest part of the neck, where spores had settled through gravity, and the broth rapidly clouded over. This not only disproved spontaneous generation, but also demonstrated the ubiquity of microorganisms in the air.

Today, as then, caterpillars are particularly bothersome, one of several insect pests that afflict the cabbage family. The green caterpillar of the imported cabbage worm is familiar to anyone who has ever grown broccoli, cauliflower, collards or cabbage. Richard Bradley, a member of the Royal Society and first botany professor at Cambridge University, writing in "The Gentleman and Gardener's Kalendar" (1720), also recognized the vast potential these insects have to reproduce, saying:

Many authors recommend placing cabbages at a distance from trees or hedges, and while that would have no effect in controlling the cabbage caterpillar, this may actually be good advice for combatting another pest of cabbage: the cabbage flea beetle. The flea beetle shelters in vegetation on the edges of gardens or fields, so placing your plants away from hedges may have some benefit. The cabbage flea beetle is a pest on canola crops in the northern United States today, and research from Washington State University has shown that flea beetle damage on canola seldom occurs farther than 50 yards (46 meters) from the edge of a field.

"Many Farmers' and Gardeners' Bean-Crops in the Spring-season of 1746, where the Seed was sown or set too early … their Horse-beans in particular suffered much by the destructive Dolphin Fly, bred by the frequent Showers of Rain, and the hot Glades or the Sunbeams that interposed their scorching Rays between their falling, and produced this horrid Insect, which no Manure, sowed over the Ground, can prevent: but I will here make known a Way to prevent this Collyer Fly's Damage … These black Dolphin Flies always begin their Settlement on the top part of the Bean-stalk, and there carry on their Increase till they get down almost to its bottom, and live on the Sap of it, by which they poison and destroy it … I am the first Author that discovered this Remedy, and this is, when a Crop of Horse-beans is perceived to be seized by this Dolphin Fly: Then let a Man make use of a Scythe, and go in among them, and mow their Tops off so far as the Fly has settled … when all the Tops are cut off, the Fly falls with them on the Ground, and can never rise again."

" . . . there cannot be a more pernicious Enemy than Snails, which you may in a Dewy Morning easily find where they most delight to feed; but the surest way is in the hard Winter to seek our their haunts, and make a clean riddance of them: They lie much in the holes of Walls, behind old Trees, under Thorn, and other old and close Hedges. In one Year, I caused near two Bushels to be gathered in a Nobleman's Garden, which had in precedent Years destroyed the most of their Wall-Fruit, and ever after they had great plenty of Fruit."

Drought, of course, does not produce aphids, but the damage from aphid feeding is much more pronounced in drought conditions, which likely explains the phenomena that Worlidge observes. It is probably aphids that gave the ant a bad name among 18th-century gardeners. Ants are attracted to the honeydew emitted by aphids, and like an army of farmers, "milk" the aphids for the honeydew and protect their "herd" from predators. Ants do not damage plants themselves other than in aiding the aphids, but most 18th-century gardening works give ideas for killing these relatively harmless insects.

"In Switzerland, however, they are transported to trees for a different purpose: the destruction of caterpillars and other vermin. A bag filled with ants is fastened to a tree, with a small hole purposely left open for them to creep out; they spread along the tree, and are prevented from leaving it, by a quantity of pitch with which the stem is covered. Rather than die by famine, they go in pursuit of the caterpillars among the leaves and devour them."

The imported cabbage worm was introduced first to Quebec and did not find its way to Massachusetts until around 1869. The flea beetles that infested the English cabbage and turnips did not arrive in America until the 20th century. The species of slugs and snails plaguing Britain arrived in America sometime in the 19th century, and to this day, I have never seen a black bean aphid on my broad beans. New World pests such as the Colorado potato beetle and the Mexican bean beetle never made it within a thousand miles of Virginia in the 18th century.

There were a few garden pests waiting for the colonists in North America, such as the cabbage looper and striped cabbage caterpillar that gardeners occasionally see today. The striped cucumber beetle is native to North America as is the squash vine borer. John Randolph, last Royal Attorney General of the colony of Virginia (a loyalist who returned to England in 1775), writing in "A Treatise on Gardening" (1793) from Williamsburg in the 18th century, gives this warning concerning raspberries: "They are pestered with lice, but limewater kills them, if sprinkled upon them." However, very few insect problems are recorded by our colonial predecessors in the vegetable garden.

Robert Beverley Jr., a gentleman, historian and politician in colonial Virginia observed in "History and Present State of Virginia" (1705) that "A Kitchin-Garden don't thrive better or faster in any part of the Universe, than there. They have all the Culinary Plants that grow in England, and in far greater perfection" — a finding due, in part, to the fact that English vegetables did not arrive in America with their English pests.