For Charles Darwin, the grapevine was exceptional in illustrating so powerfully his theory of the modification of species. But did his work, in turn, play a crucial role in overcoming the phylloxera crisis and saving viticulture as we know it today? Professor Michael Summerfield delves deep into Darwin’s correspondence and ponders whether this might indeed be among the many remarkable achievements of one of the towering figures in modern science.
The Darwin Correspondence Project began publishing all the known extant letters of Charles Darwin in 1985, and its 30th and final volume appeared after nearly four decades, in 2022.1 The early correspondence traces Darwin’s nascent interest in natural history, then it proceeds to record his epic five-year voyage around the world on the surveying ship HMS Beagle, before expanding into his work on evolution and the diverse array of geological and biological topics that occupied him for the rest of his life. Containing more than 15,000 letters to and from Darwin, it has been a monumental endeavor of meticulous research and editing that has created an extraordinarily detailed insight into the intellectual and personal life of one of the towering figures of the 19th century. Its completion prompts thoughts about what his ideas contributed to our world, and with Darwin there are so many avenues to consider. But what of wine? Nothing much to consider here, surely. Well, perhaps there is, and I would like to pose this question: Did Darwin save wine?
Wine and the greatest of all pleasures
Charles Darwin was born in Shrewsbury, England, in 1809. His encounters with wine were similar to those of many other wealthy, middle-class men in 19th-century Britain. His father, the physician Robert Waring Darwin, was strictly teetotal, but Charles consumed wine regularly throughout much of his adult life, both for recreation and medication. During his student years at Cambridge, he said he drank “many a glass of wine” and later confessed in his autobiography that he associated there with some “dissipated low-minded young men” and “sometimes drank too much.”2 Later he admitted to his close friend and confidant, the botanist Joseph Hooker, that “he had got drunk three times in early life, and thought intoxication the greatest of all pleasures”; and in 1854, after a visit to London, he wrote to Hooker commenting rather flippantly that he had begun “to think that dissipation, high-living, with lots of claret, is what I want.” However, according to the physician Ralph Colp, who extensively researched his domestic life and health, Darwin was also concerned about the dangers of drunkenness.3 His paternal great-grandfather and grandmother had both died from alcoholism, and it is possible he thought alcoholism was an inherited characteristic; and his paternal grandfather, Erasmus Darwin, had spoken in public of the toxic effects of alcohol. Darwin also wrote to Benjamin Richardson, a leading figure in the temperance movement in Britain, saying that “no cause has led to so much suffering and inherited ill-health as the consumption of alcohol.”
After his occasional student excess, Darwin’s recreational consumption of wine throughout the rest of his life was moderate, but not without interest. In 1857 he wrote to Syms Covington, who had been his personal servant during the Beagle voyage and had then emigrated to Australia, saying how he had “lately dined with one of your great Australian potentates, Sir W. Macarthur, and heard a good deal of news of Australia, and drank some admirable Australian wine.” In Darwin’s old age, his sons George and Francis assisted him in acquiring wine, with George writing to him in the last year of his life about a corked bottle of Champagne purchased from the London wine merchants Carbonell & Co. In these years Darwin regularly drank a glass of Sherry at lunch and supper, and in 1874 George wrote to his father to let him know that he had informed Carbonell that they would “return the brown sherry & to send some other different & drier.”
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Darwin suffered from ill-health throughout his adult life, and as was common practice at the time, he was prescribed wine as part of his treatment. Despite his personal abstentionist beliefs, his physician father had prescribed Port for fevers in children, and this treatment was also applied to Charles Darwin’s own children—one of his sons, who had scarlet fever, lived on “Port-wine every 3/4 of an hour day & night.” Darwin had even treated himself by “eating cinnamon and drinking port wine” during a feverish episode while on the Beagle voyage. After Darwin moved to Down House in Kent in 1842, Mr Williams, the family physician, prescribed wine when he had bouts of ill-health; in 1858 Darwin wrote to one of his sons that “Mr Williams has ordered me a jolly prescription of two glasses of wine at dinner & he wished me to take three.” Darwin consulted various physicians throughout his life, and in 1860 a Dr Headland prescribed “drinking some wine” as part of his medical regimen. Two months before his death, Darwin wrote in a private letter to a journalist that he drank “1 glass of wine daily and believe I should be better without any, though all Doctors urge me to drink some or more wine as I suffer much from giddiness.”
When Darwin was considering whether to join the round-the-world surveying expedition of HMS Beagle in 1831, the prospects for wine drinking were not encouraging. He wrote to his sister Caroline describing his meeting with the commander of the ship, Robert FitzRoy, for whom he was intended to be a gentleman companion. (FitzRoy was aware of the social isolation of the commander of British naval vessels on long voyages—his predecessor on the Beagle had died by suicide in Tierra del Fuego.) Darwin reported to his sister that “If I live with him he say I must live poorly, no wine & the plainest dinners.” But in the event, shore visits during the voyage provided plenty of opportunities to experience the local wines, as is suggested by a letter from Caroline sent to catch Darwin at Rio de Janeiro. She wondered why the family back in Shrewsbury had not heard from him and speculated that it was due to him having “got so much good wine at the Madeiras.” While the record of wines that Darwin experienced on the Beagle voyage is meagre, he did have an intriguing encounter with a pioneer of Australian viticulture, James Busby. The meeting took place in December 1835 on the North Island of New Zealand, where the Beagle had dropped anchor in the Bay of Islands.
Brought up in Edinburgh, James Busby emigrated to Australia in 1824—a year before Darwin began his medical education at Edinburgh University. Busby had already spent time in France studying viticulture, and on the voyage to Australia he began the first of his three books on the subject. His major contribution to Australian viticulture was the introduction of a large collection of European vine varieties that subsequently helped to develop that country’s wine industry. In 1833 Busby took up the position of British Resident in New Zealand; based in Waitangi, this quasi-diplomatic role involved acting as an intermediary between the Maori population and European settlers, although he received no direct administrative or military support from the British government. Darwin described meeting him in his account of the Beagle voyage published in 1839, explaining how Busby had arranged a guide and provided a lift in his boat to aid an onshore excursion to the missionary settlement of Waimate.4 Busby’s name also appears several times in a letter on missionary activity that Darwin and FitzRoy had published in a South African Christian newspaper, citing him as a valuable source of information on Maori life.5 And before the Beagle left New Zealand, Busby provided Darwin with a letter of introduction to an acquaintance in Sydney, describing him as “a Geologist who has spent several years in examining the Mountains of South America.”
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Vines, grapes, and the modification of species
Once the Beagle returned to England in 1836, Darwin had to consider his future. He had the freedom of an independent income provided by his wealthy father, but he decided to abandon a life of exploration furthering the geological studies that had been his focus on the Beagle voyage. Instead, he chose to get married (to his cousin Emma Wedgwood, of the famous pottery dynasty) and settle down to a family life in the country near London. Limited geographically by this commitment—Darwin never left Britain again—he began to work tirelessly to gather evidence in support of his evolutionary ideas and later developed his botanical interests. Extensive grounds around the family home—Down House, in the village of Downe in Kent—provided room for glasshouses and other facilities for research and study, and he trained his gardeners to assist with his experiments and observations. At the same time, his copious letter writing developed a worldwide network of correspondents that supported and informed his numerous fields of scientific enquiry.
Darwin’s botanical studies became a relaxation and an antidote to the stress caused by the waves of criticism that his evolutionary ideas unleashed after the publication of On the Origin of Species in 1859. Self-deprecatingly claiming to Joseph Hooker that he was not a botanist, but “a man who hardly knows a daisy from a dandelion,” Darwin generally avoided the detailed taxonomic and morphological studies that were the mainstay of contemporary botanical research; rather, his experiments on plants were designed to explore the ramifications of his theory of evolution by natural selection proposed in Origin. In the early 1860s, Darwin was looking at climbing plants, being fascinated by the way they attached themselves using specific structural adaptations. A grapevine grew up a wall of Down House, and among the species he studied were those of the genus Vitis. Several pages of his book on climbing plants are concerned with Vitis vinifera and focus on the growth and movement of the vine’s tendrils.6 Darwin observed how they “move spontaneously from side to side” making elliptical revolutions, but that they also appeared to be sensitive to light. He concurred with the view of a number of other authors that vine tendrils are modified flower peduncles—the stalks that bear flowers and fruit. But he emphasized that an individual vine could yield “every possible gradation between ordinary flower-stalks for the support of the flowers and fruit, and tendrils used exclusively for climbing,” and saw this “as striking and curious an instance of transition as can well be conceived.” So, for Darwin, the grapevine was exceptional in illustrating so powerfully his theory of the modification of species.
Having developed his idea of natural selection soon after returning from the Beagle voyage, Darwin spent much of the next two decades accumulating evidence to support his theory. His plan was to publish a large volume incorporating all this evidence, but he was forestalled by a letter he received from fellow naturalist Alfred Russel Wallace that enclosed a draft of a scientific paper outlining a theory of species modification extremely close to Darwin’s own. A paper comprising contributions from both Darwin and Wallace was presented to the Linnean Society in London in 1858, but wanting recognition of his priority, given that he had been working on his theory for the previous two decades, Darwin immediately embarked on writing a short book—or abstract, as he called it—summarizing his theory and the evidence to support it. This was the edition of On the Origin of Species published in November 1859, but Darwin still retained an ambition to produce his “big species book.”7 The plan was never completed, but he did marshal his vast accumulation of notes on domesticated animals and plants into a substantial work published in 1868.8 The Variation of Animals and Plants Under Domestication is a greatly expanded treatment of Chapter 1 of Origin, and it contains a revealing section on the grapevine and its varieties.
In the book, Darwin first describes the geographical origin of the European cultivated vine and comments on how the number of “semi-wild” forms found in southern Europe may have escaped from cultivated forms given the variability of some of these. In particular, he notes how “the vine varies much when propagated by seed” and how new varieties “are produced almost every year.” In his account of varieties of Vitis vinifera and their particular characteristics, he relies much on Odart’s Ampélographie Universelle, published in 1849. Darwin records that “[c]ertain grapes called Nebbiolo […] present a constant character” and that a “Rhenish variety […] likes a dry soil” but is apt to rot if “much rain falls.” Some varieties “have the fault of being too much excited by the April sun, and in consequence suffer from frost,” whereas a “Styrian variety […] has brittle foot-stalks, so that the clusters of fruit are often blown off.” Darwin then goes on to mention “the vine disease in France”—by which he means the oidium (powdery mildew) that had invaded French vineyards in the 1840s as a result of the importation of infected American vines—and comments how some groups of grape varieties suffered much more from it than others, such as “the true old Burgundy.” He observes that American vine species in France “entirely escaped the disease,” and he concludes that “those European varieties which best resist the disease must have acquired in a slight degree the same constitutional peculiarities as the American species.” Darwin also records instances of variations in fruit color and form on the same individual vine, along with efforts to produce particular vine characteristics and the outcomes of grafting—topics that interested a number of those with whom he corresponded. Some such correspondents also sent him grapevines on which to experiment, such as a gift in 1872 from English nurseryman Thomas Rivers of a rootstock of “Frontignan” and a scion of “Chasselas Noir” for grafting. The vines were perhaps received by Darwin at his request, because in his reply to the accompanying letter he commented that “the experiment will be more difficult than I had expected.”
Darwin also addressed the environmental constraints on viticulture in Europe. He noted how “the line of practical culture has retreated a little southward since the middle ages,” but he thought that this may be due to commercial factors, given that wine had become more freely available. He concluded that “acclimatisation has made no progress during several centuries,” as viticulture had not spread northward, and he pointed out how different grape varieties are suited to different climates, with some “hardy, whilst others, like the muscat of Alexandria, require a very high temperature to come to perfection.” Darwin was introduced further into the realm of terroir in a letter from WC Tait, a botanist resident in Oporto, who wrote to him that “the effect of soil on the vine for Port Wine cannot be produced at Oporto even with the proper vine” but only in a “certain district in the neighbourhood of Regoa and Lamego” (inland in the Douro Valley).
Darwin’s interest in domesticated plant (and animal) species modified by intentional human selection was a crucial complement to the argument for evolution by natural selection that he presented in Origin; indeed, the chapter on “variation under domestication” precedes the one on “variation under nature.” Expressed in its simplest form, Darwin’s idea of natural selection was this: Offspring resemble their parents but vary from them. More offspring are born than can survive. Those that are most likely to survive and reproduce—and thereby pass on their characteristics to the next generation—are those that are best adapted to their environment. Thus, over time species can become modified, and given certain conditions—for instance, isolation in a geographical area—new species can arise. Intentional selection could modify domesticated plant and animal species, but a parallel natural process could also promote modifications to the point of creating new species over the immense expanses of geological time.
Darwin saw external conditions, such as climate and food resources, as only one element of an organism’s environment-driven modification, emphasizing that the way in which one species interacts with another is also an important mechanism. In the very first paragraphs of Origin, Darwin highlights the process of what he termed “coadaptation”—how species adapt to each other, such as the pollination of particular plant species by a particular insect species, or the resistance of a type of plant to a pathogen. He argued that such phenomena were inexplicable in terms of contemporary ideas about how evolution occurred, but that coadaptation between species could be accounted for by his process of natural selection.9 From the early 1860s, Darwin published a number of articles and a book devoted to the “contrivances” (especially the shape of flowers) that enable orchids to be fertilized by their specific insect pollinators. These ideas of evolution and coadaptation deeply impressed Missouri’s state entomologist Charles Valentine Riley, someone much concerned with the relationships between insect pests and crops, and a key player in the drama of the phylloxera crisis that devastated the wine industry of France, and much of the world, in the second half of the 19th century.
The phylloxera curse and cure
Born in London in 1843, Riley emigrated to America in 1860, and through working on an agricultural journal based in Chicago he became acutely aware of the damage to crops caused by insects. He rapidly developed his knowledge and established a network of correspondents among the foremost entomologists in America, including Benjamin Dann Walsh, another British-born immigrant who had known Darwin at Cambridge and had visited him in his rooms at Christ’s College. Walsh read Origin in 1861; unlike many entomologists of the time, he was rapidly convinced by Darwin’s evolutionary theory and became an enthusiastic advocate. He introduced Riley to Darwin in a letter in 1868, and he also sent him reprints of Riley’s papers. Walsh became something of a mentor to Riley; like his senior, Riley also became a fervent Darwinian.10 In 1868, the Missouri legislature decided to establish the position of state entomologist, and Riley was appointed. He published annual reports, which he sent to Darwin, and we know that Darwin studied them carefully, because they are full of his annotations; for instance, he marked a passage on phylloxera in Riley’s fourth Annual Report, published in 1872, and he cited this in the second edition of The Variation of Animals and Plants Under Domestication, published in 1875. As well as corresponding with Darwin, Riley visited him on two occasions at Down House, in 1871 and 1875. He later wrote: “The Darwin residence is a plain, but spacious, old-fashioned house of the style so common in England, and which, with the surrounding well-kept grounds and conservatory, convey that impression of ease and comfort that belong to the average home of the English country gentleman.”11 Riley mentioned seeing a copy of one of his annual reports in Darwin’s study “with many leaves turned down.”
Soon after his appointment as state entomologist, Riley became aware from French and English publications of the phylloxera infestation in France, and in 1869 he began communicating with French colleagues facing the crisis. The yellowing of leaves and blackening of roots, signaling the presence of phylloxera, appeared in the southern Rhône Valley in the early 1860s and then began to spread rapidly.12 By 1868, the situation was sufficiently serious for a committee of experts to be assembled in Montpellier, a center of botanical research. Led by Jules Emile Planchon, professor of pharmacy at the University of Montpellier and botanist at a national facility in the city, the committee immediately established that an aphid-like insect (initially given the name Phylloxera vastatrix but now known by the scientific name Daktulosphaira vitifoliae) was responsible for killing vines by infesting their roots and extracting the sap. And it was soon appreciated that, like oidium, phylloxera had been brought from America on imported American vines. (Data from recent genetic studies confirm that there were at least two independent introductions of phylloxera into European vineyards, one of which had its origins in American species imported from the northeast coast of America where Vitis riparia and Vitis labrusca dominated.13)
By 1870, the crisis had become national, with the Ministry of Agriculture offering a monetary prize for an effective cure for the disease. Having already inferred that the root-sucking phylloxera of France was the same organism long known to infest the leaves of American vines, Riley visited Planchon in Montpellier in 1871. Planchon was fluent in English and familiar with the anglophone scientific literature, having spent time at the Royal Botanic Gardens at Kew, near London, so he was well placed to benefit from Riley’s expertise. In 1872, in a farsighted move, the French authorities sent Planchon on a tour of the United States to learn all he could about phylloxera there.14 Riley met him off the ship in New York and accompanied him in visiting vineyards, nurseries, and botanic gardens. Planchon was initially skeptical about Darwin’s ideas, but he soon became more receptive, probably as a result of discussions with Riley, who was clearly basing his understanding of phylloxera on Darwinian theory. For instance, in his third Annual Report, published in 1871, Riley made an explicit Darwinian argument that American vine species had become resistant to the effects of phylloxera because vine and pathogen had evolved together. After returning from his visit to America, Planchon wrote: “It is possible that natural selection has eliminated those American vines which could not fight the enemy [phylloxera]. This hypothesis proposed […] by Mr. Riley would explain why some American vines survive, while others are only mildly resistant, and others have disappeared.” The idea emerged of either planting American species in France or grafting French varieties onto the phylloxera-resistant rootstock of American vines. American species were known for their unpleasant flavors, and grafting was presented as the favored solution to the crisis. However, big questions remained: How would American rootstock perform in the different climates and soils of France? And, more fundamentally, was the phylloxera bug actually the cause of the disease or did it simply affect already weakened and vulnerable vines?
At the time of the phylloxera outbreak, the predominant view of disease in the Western world was that it was the result of the environment, not of an individual active agent such as a tiny insect. In this “disease as effect” view, phylloxera was the consequence of poor viticultural practices or vine cultivation in unsuitable locations, with the root-sucking insects only affecting already weakened vines. The “disease as cause” theory being proposed by Planchon and Riley, based on Darwinian natural selection and coadaptation, was widely opposed in French academia, with Darwin’s ideas being described as “deficient in the basic rules of logic” in 1864 by the then president of the Académie des Sciences in Paris. If the environment was the critical factor, what guarantee was there that American vines transported to French vineyards would retain their resistance to phylloxera in the different soils and under the different climates encountered there? This question could not be effectively countered by Darwin’s advocates, because his theory contained no convincing mechanism for transmitting inherited features between generations—something that was not fully understood until later advances in genetics. There was also a strong cultural resistance in the French establishment to the idea of “contaminating” French vines with American rootstock, so other solutions were proposed.15 Initially, quarantines were imposed on infected areas, but the complex life cycle and myriad forms of the phylloxera bug were soon able to overcome these. Flooding vineyards was found to work locally and temporarily, but it was chemical treatments aimed at killing phylloxera where it dwelt underground that was most widely adopted. By 1875, insecticide production was on an industrial scale, and in 1879 the importation of American vines into France was banned by the Ministry of Agriculture, except for areas already completely devastated by phylloxera. Insecticide application, usually based on carbon disulfide, became the sanctioned treatment elsewhere.
The chemical strategy for phylloxera control was expensive and did not halt the destruction of vineyards, especially in economically poorer areas. In his eighth Annual Report as Missouri’s state entomologist, Riley contrasted the scene he encountered in France in 1875 with his earlier visit in 1871, seeing vineyards “fast disappearing” and the land being converted “entirely or partly to other crops.” But in the midst of all this destruction, he found the American vines flourishing, and he proclaimed that those vignerons who had “grafted their own varieties on to the roots of ours were elated at the prospect.” The debate came to a head in the 1880s, when the superiority of grafting existing European vine varieties onto American rootstock eventually gained wide acceptance. Much work remained to be done, though, especially in identifying suitable rootstocks for the various soil conditions encountered in French vineyards. However, by the end of the decade, the large-scale replanting of many of the prestigious vineyards of Bordeaux and Burgundy had begun; many, but not all—La Romanée-Conti was not replanted with grafted vines until 1947.
The phylloxera crisis had been a disaster for rural France, and subsequently for many other viticultural regions around the world. Over the two decades from 1865, the area of French vineyards declined by more than 50 percent, and wine production fell by almost a half. Some wine-producing regions of France never recovered. The geography of viticulture in France, and in the wider world, had changed.
So, did Darwin save wine?
No, not directly, but his ideas were of great significance in the grafting solution to the phylloxera crisis. Darwin was very aware of what was going on in vineyards in France and elsewhere in Europe, commenting in 1881 in a letter to Sir William Thiselton-Dyer, the then director of the Royal Botanic Gardens, Kew, that “I have always watched with interest the Phylloxera & Vine case.” In 1878, in a letter to the previous director, his friend Joseph Hooker, Darwin had asked him to “Pray reflect on difference in varieties of Vitis in resisting Phylloxera.” And from 1876, Darwin corresponded on the topic with James Torbitt, an agriculturalist based in Belfast, Ireland. He was attempting to develop a blight-resistant variety of potato by preserving and propagating seed from resistant individual plants, and he considered that his approach would apply equally to producing phylloxera-resistant vines. In 1879, Torbitt reported to Darwin the results of an experiment of a resistant vine from a phylloxera-infested district in Portugal and noted how “the people are ‘delighted’ by the vigorous growth of the new plants.”
Although there is no evidence that Darwin directly involved himself in experiments on phylloxera, his contribution to solving the phylloxera crisis was nonetheless profound. Through fortunate timing, his ideas on evolution by natural selection—and especially the way it accounted for coadaptation—were published just before phylloxera erupted in the south of France. The immediate impact of Darwin’s ideas on American entomologists such as Walsh and Riley, together with the awareness of Planchon in Montpellier of the mechanism of natural selection, provided a scientific basis for the practical solution to the problem of grafting resistant American rootstock to European vine varieties. No doubt this approach would eventually have been accepted anyway, given the impracticality and cost of other strategies, but Darwin and his revolutionary idea of how evolution occurs provided the scientific foundation for the adoption of the grafting strategy in the face of deep-rooted institutional and cultural resistance. ▉
Notes
1. In printed form, see F Burkhardt et al (eds), The Correspondence of Charles Darwin, 30 volumes (Cambridge University Press, Cambridge; 1985–2023). The correspondence, along with Darwin’s publications and manuscripts, is available via the Darwin Online website (darwin-online.org.uk). All references to Darwin’s correspondence included here were sourced through this website.
2. F Darwin (ed), The Life and Letters of Charles Darwin Including an Autobiographical Chapter, three volumes (John Murray, London; 1887).
3. R Colp Jr, To Be an Invalid (University of Chicago Press, Chicago; 1977).
4. First published as C Darwin, Journal and Remarks 1832–1836, Volume III of R FitzRoy (ed), Narrative of the Surveying Voyages of His Majesty’s Ships Adventure and Beagle Between the Years 1826 and 1836, three volumes (Henry Colburn, London; 1839). For more on James Busby, see Alex Maltman, “Brisk Wine from Granite but Delicate from Sand: The Geological Legacy of James Busby (1802–71),” WFW 75, pp.104–09.
5. R FitzRoy, C Darwin, “A Letter, Containing Remarks on the Moral State of Tahiti, New Zealand, &c,” South African Christian Recorder 2 (1836), pp.221–38.
6. Initially published as C Darwin, “On the Movements and Habits of Climbing Plants,” Journal of the Proceedings of the Linnean Society of London, 9 (1865), nos 33 and 34, it subsequently appeared as a second edition in book form as C Darwin, The Movements and Habits of Climbing Plants (John Murray, London; 1875).
7. C Darwin, On the Origin of Species by Means of Natural Selection (John Murray, London; 1859).
8. C Darwin, The Variation of Animals and Plants Under Domestication, two volumes (John Murray, London; 1868).
9. I am grateful to Ben Bradley, friend and Darwin scholar, for pointing out to me just how important Darwin considered coadaptation to be as evidence for his theory of evolution by natural selection.
10. On Riley, Walsh, and their relationship to Darwin, see G Kritsky, “Darwin, Walsh, and Riley: The Entomological Link,” American Entomologist 41 (1995), pp.89–96; EH Smith, JR Smith, “Charles Valentine Riley: The Making of the Man and His Achievements,” American Entomologist 42 (1996), pp.228–38.
11. CV Riley, “Darwin’s Work in Entomology,” Proceedings of the Biological Society of Washington DC 1 (1882), pp.70–80.
12. On the phylloxera crisis, see G Gale, “Phylloxera vastatrix, devastator of vines,” WFW 2, pp.46–51; C Campbell, Phylloxera: How Wine Was Saved for the World (Harper Collins, London; 2004); G Gale, Dying on the Vine: How Phylloxera Transformed Wine (University of California Press, Berkeley and Los Angeles; 2011).
13. J Tello et al, “Major Outbreaks in the Nineteenth Century Shaped Grape Phylloxera Contemporary Genetic Structure in Europe,” Scientific Reports 9, 17540 (2019); doi.org/10.1038/s41598-019-54122-0
14. On the cooperation between French and American researchers during the phylloxera crisis, see A Fusonie, “Missouri and France: The Charles Valentine Riley Connection,” Journal of the Kansas Entomological Society 69 (1996), pp.109–21; Y Carton et al, “Une coopération exemplaire entre entomologistes français et américains pendant la crise du Phylloxera, France (1868–1895),” Annales de la Société Entomologique de France 43 (2007), pp.103–25; WC Sorensen et al, “Charles V Riley, France, and Phylloxera,” American Entomologist 54 (2008), pp.134–49.
15. For an interesting analysis of the opposing positions in the phylloxera debate in France and how they were resolved, see W Kwon, P Constantinides, “Ideology and Moral Reasoning: How wine was saved from the 19th century phylloxera epidemic,” Organization Studies 39 (2018) pp.1031–53.
