More and more people are demanding organic fruit and vegetables, and traditional growing methods are enjoying a resurgence in popularity. But were things really better before? Horticulturalist Inger Olausson researches plant protection from a historical perspective.
“At the turn of the 20th century, spraying fruit trees with lead arsenate was recommended at least four or five times a year to protect against pests,” she says.
Inger Olausson shows us around the greenhouses in an idyllic location alongside the River Tidan in Mariestad. The School of Landscape Gardening stands on the other side of the river, where researchers and students specialise in horticulture, landscape preservation and building crafts. Even this early in the spring, the sun provides pleasant warmth in the unheated greenhouse where the radishes are already starting to peep out of the ground.
We sit down in the greenhouse, where Inger feels quite at home despite not coming here particularly often. Her father was a gardener, and she inherited his green fingers early on. She studied horticulture at the Swedish University of Agricultural Sciences, where she also wrote her thesis on the development of plant nurseries during the first half of the twentieth century. The history of gardening is relatively unknown, and this is a field of study that she shares with only a few other researchers.
“Exploring new areas is both enjoyable and challenging,” she smiles.
her current project involves studying plant protection in gardening, primarily within commercial enterprises: How outbreaks of diseases and pests were prevented and dealt with when growing fruit, vegetables and flowers from the early 19th century up until 1945. By then, DDT – an incredibly effective pesticide – had been introduced to plant cultivation.
“DDT eradicated almost everything, which meant that pests’ natural enemies were also wiped out. This led to a situation where there was no protection at all, and those pests that had managed to avoid the poison or had developed resistance had free rein.”
the introduction of ddt had consequences not only for the environment but also for the development of other plant protection methods. As early as the 1920 s and 1930 s, intense research into biological pest control – introducing pests’ natural enemies – had been carried out in many countries. One example is predatory mites. However, all this research came to an end with the introduction of DDT.
“When DDT was banned in the 1970s, research resumed – with Sweden at the cutting edge.”
But why did the use of these toxic chemicals in gardening increase? As Inger explains, there were a number of reasons. The late 19th century saw growing imports of products to Sweden, leading to both greater competition and the introduction of new pests and diseases. Imported apples had a completely different visual quality to domestic apples.
“There was a real focus on quality, and fruit had to be of the highest class in order to fetch a good price.”
the imported fruit was spayed, often with pesticides containing arsenic. This led to Swedish growers using more and more chemical pesticides, such as the arsenic-containing pigment Paris green, which was replaced by lead arsenate and subsequently zinc arsenate. Another reason for the rise in the use of chemical plant protection products was that using cold frames and greenhouses became increasingly common. Greenhouses were used all year round, and here it was not only the plants but also pests and diseases that survived, and these were tackled with nicotine, prussic acid, mercury, formalin and other substances.
“The use of chemicals also increased within wider society, and it was easier to simply use sprays, gases or powders instead of having to crush insect larvae. It was also harder to find workers when others were able to offer higher wages or summer holidays, forcing the green industries to streamline their methods.”
inger’s research findings will eventually result in a book, which she hopes to complete next year.
“It won’t be a handbook, but I hope it’ll provide a longer-term perspective on the debate about organic or conventional growing methods and spread knowledge about old methods that we can still use today.”
Plant protection in gardening over the years
WHERE? At the Department of Conservation in Mariestad, which brings together knowledge about horticulture, landscape preservation and building crafts.
HOW? By studying everything from gardening handbooks to accounts from individual companies. There is currently no collected documentation on the history of the horticultural industry.
WHY? Because there is a lack of combined knowledge about horticultural history and plant protection over the years, an area that is becoming increasingly topical with the development of organic growing.
Position: Academic researcher at the Royal Swedish Academy of Letters, and Senior Lecturer in Conservation specialising in gardening at the University of Gothenburg.
Other information: Member of the Royal Swedish Academy of Agriculture and Forestry, and of ‘swedish Academy’ which promotes Swedish culinary heritage. Did you know that more than 50 varieties of swede grow in Sweden?