Fastidious Triads: An Environmental History of Xylella fastidiosa (1882–2020)

In this Work in Progress (WiP) seminar, Christian Colella presents "Fastidious triads", a study that reconstructs the social and environmental history of the plant pathogen Xylella fastidiosa between 1882 and 2020. Rather than approaching Xylella through the recent European outbreak alone, the project follows the pathogen across different historical periods, crops, insect vectors and agricultural landscapes, connecting three main contexts: Pierce’s Disease in California, Citrus Variegated Chlorosis in Brazil, and the more recent outbreaks affecting olive and almond cultivation in Europe.

At the centre of the research is the pathogenic triad formed by bacterium, insect vector and host plant, and the ways in which this triad gradually became an object of scientific inquiry and phytosanitary intervention. The project examines how knowledge and practices concerning Xylella were produced, stabilized, circulated and contested across different scientific, political and ecological settings, paying particular attention to changing epistemic cultures, forms of expertise and non-knowledge, and relations between researchers, growers, institutions and social movements.

Electron micrographs (Wells et al., 1987) marking the formal description and naming of Xylella fastidiosa.

Combining environmental history, Science and Technology Studies, and political ecology, the research adopts a transnational and pathosystem-centred perspective. Following the movements of the pathogen, its vectors and host plants, it also investigates the circulation of academic knowledge across different geographical contexts and the role of monocultures, commodity chains and the global circulation of live plants in shaping the emergence and management of plant disease. In doing so, the project uses Xylella as a historical lens through which to examine changing relations between science, agriculture, environmental governance and ecological transformation.

Commentator: Agustí Nieto Galan (UAB)

Christian Colella is a post-doctoral Beatriu de Pinós researcher. He works at the intersection of science and technology studies (STS), environmental history, and political ecology. He holds a PhD in Applied Sociology and Social Research Methodology from the University of Milano-Bicocca, as well as an MA and a BA in Social and Cultural Anthropology.

If you are interested in reading the entire text in advance —highly recommended, since the WiP seminar format presupposes prior reading— you can request it from Christian.Colella@uab.cat or Laia.Torres.Casas@uab.cat.

Remember that you can bring your lunch on site, as we will have a lunch-seminar format, rigorous and informal at the same time.