Grapevine trunk diseases (GTD) can lead to substantial economic losses at the farm and/or winery scale. The presence of GTD causing pathogens, Phaemoniella Chlamydospora, Phaeoacremonium minimum and Diplodia seriata have been confirmed in vine nursery cuttings. German researchers investigated whether hot water treatment (HWT), in combination with the use of Trichoderma spp. (Fungal biocontrol) in the nursery, will it reduce infections of GTD in nursery vines?
Project layout
Firstly, researchers developed an HWT protocol in vitro and on inoculated wood to determine the heat tolerance of the pathogens as mentioned above. This was followed by a nursery trial under practical conditions on inoculated scions to investigate the efficacy of HWT alone, and in combination with Trichoderma. Finally, the same procedure was applied to naturally infected scion cuttings. Pathogen detection was done using PCR lab tests.
Results
- minimum had greater tolerance to HWT than P. chlamydospora.
In the nursery experiments conducted in 2021 and 2022, all three pathogens exhibited varying recovery rates after HWT over a 12-month monitoring period.
The combined applications of HWT and Trichoderma protected the planting material over the entire twelve-month assessment period.
Assessment at 12 months post-HWT indicated a 90% recovery rate of Trichoderma.
HWT effectively reduced GTD pathogens in grapevine planting material, and the combined treatment with Trichoderma induced long-lasting protection in the nursery.
Significance of the study
Although conditions and stresses on vine planting material in South African nurseries differ greatly from those in Germany, research findings like these might be replicated in a South African context using different or adapted methods. Providing the South African vine industry with improved plant breeding methods, ultimately leading to more resilient planting material.
Reference:
Simon, D. A., Winterhagen, P., Walter, R., Wetzel, T., Kortekamp, A., von Tiedemann, A., & Eder, J. (2025). Hot water treatment combined with Trichoderma inoculation in the nursery protects planting material against grapevine trunk disease. OENO One, 59(2). https://doi.org/10.20870/oeno-one.2025.59.2.8385