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Could irrigation water be a Fusarium source in tomato fields?
Quick find: this post is based on the published summary (abstract) of the study, not the full paper.
Fusarium taken from irrigation water and Fusarium taken from diseased tomato plants in Australian processing tomato fields shared a genetic background. In glasshouse tests, every isolate the researchers tested was able to cause disease in processing tomato.
Water was one of the places this team went looking. The Fusarium oxysporum species complex (FOSC) includes important soil-borne pathogens of a range of crops worldwide, and in Victoria and New South Wales it has been identified as the cause of stunting and poor growth in processing tomato fields, resulting in significant yield losses. The researchers wanted to know how varied these fungi are and how hard they hit tomato plants (Feng et al., 2026).
What this means for your grow
The authors draw one practical point about water. The authors say the shared genetic background of the isolates from irrigation water and from plants highlights irrigation water as a potential source of inoculum in Fusarium epidemics, and that this matters for disease management in Australian processing tomato systems. In the glasshouse, the roots took the bigger hit: root dry weight fell by 44% to 83% compared with the control, against 11% to 26% for above-ground height. The published abstract does not report testing whether the water carried the fungus to plants, or any treatment, so it flags water as a potential source of inoculum, not a proven route of spread or a fix.
What did they test and find?
- The fungi: 40 FOSC isolates, taken from symptomatic tomato plants, irrigation water samples and culture collections. All were confirmed as FOSC by genetic analyses of four genomic loci.
- A mixed bunch: there was a high level of genetic diversity among the isolates, with multiple phylogenetic lineages detected.
- Every tested isolate caused disease: in glasshouse bioassays, all tested isolates were pathogenic to processing tomato, with significant reductions in plant growth. Above-ground height was reduced by 11% to 26% and root dry weight by 44% to 83% compared with the control (p < 0.05).
- Some were worse than others: aggressiveness varied among isolates, but growth was reduced whatever their phylogenetic placement.
- Shared genetic background: isolates from irrigation water and from plant samples shared a genetic background.
What could it mean?
The authors conclude that irrigation water has a role as a potential source of inoculum in Fusarium epidemics, underscoring its significance for disease management in Australian processing tomato systems. For now this is most relevant to people managing disease in processing tomato crops and to researchers; it is not a tested recipe for a home garden.
What were the limitations?
Limitations are not reported in the published abstract. This post is based on the abstract only.
Trial details
- Who: School of Agriculture, Food and Ecosystem Sciences, The University of Melbourne, Parkville, Victoria, with co-authors from the Department of Agriculture, Fisheries and Forestry (Mascot, New South Wales), the Centre for Crop Health at the University of Southern Queensland and the Queensland Department of Primary Industries (the authors' affiliations).
- Where: tomato plants and irrigation water from Australian processing fields (the paper's title). The abstract says FOSC has been identified as the cause of stunting and poor growth in processing tomato fields in Victoria and New South Wales. Disease tests: glasshouse bioassays.
- Crop: processing tomato.
- Isolates: 40 FOSC isolates from symptomatic tomato plants, irrigation water samples and culture collections, confirmed by multigene phylogenetic analyses of four genomic loci (β-tubulin, calmodulin, the second largest subunit of nuclear RNA polymerase II and translation elongation factor 1-α).
- Design: glasshouse bioassays of tested isolates on processing tomato, compared with a control.
- Results: all tested isolates pathogenic to processing tomato; above-ground height reduced by 11% to 26% and root dry weight by 44% to 83% compared with the control (p < 0.05); aggressiveness varied among isolates; growth reduction occurred irrespective of phylogenetic placement; high genetic diversity, with multiple phylogenetic lineages; isolates from irrigation water and plant samples shared a genetic background.
- Funding: the University of Melbourne, as listed in the paper's Crossref record.
- Publication: Plant Pathology 75(4), e70256, July 2026 issue, published online 16 August 2026, https://doi.org/10.1111/ppa.70256. Licence: CC BY-NC-ND 4.0.
- Not reported in the published abstract: the farms, districts or states the plant and water samples came from; how many isolates were tested in the glasshouse; the tomato cultivar and plant age; the dates and length of the tests; the glasshouse location, potting mix, lighting, temperature and humidity; how the plants were inoculated; feeding and watering; the number of plants and replicates; and conflicts of interest.
Links
- The study: Genetic Characterisation and Aggressiveness of the Fusarium oxysporum Species Complex in Tomato Plants and Irrigation Water From Australian Processing Fields
- The institution: UniSQ Centre for Crop Health
References
- Feng, H., Callaghan, S. E., Cao, J., Taylor, P. W. J., Fuentes, S., Pang, A., Tan, Y. P., & Vaghefi, N. (2026). Genetic characterisation and aggressiveness of the Fusarium oxysporum species complex in tomato plants and irrigation water from Australian processing fields. Plant Pathology, 75(4), e70256. https://doi.org/10.1111/ppa.70256