Hot water treatment combined with Trichoderma inoculation protects planting material in the nursery against grapevine trunk disease

Abstract

Grapevine trunk diseases (GTDs), caused by a group of fungal pathogens including Phaeomoniella chlamydospora, Phaeoacremonium minimum, and Diplodia seriata, pose a serious threat to grapevine cultivation worldwide. Hot water treatment (HWT) and the biological control agent Trichoderma has been studied as potential control method against GTD pathogens in dormant planting material. Previous studies indicated that the effectiveness of HWT varies based on the target organism, whereas the antagonistic ability of Trichoderma depends on the application method as well as on the implemented strain. This study evaluated the efficacy of HWT, alone and in combination with Vintec® (Certis Belchim B. V.) containing Trichoderma atroviride SC1 (Ta SC1).

In a nursery experiment in two experimental years, the effectiveness of HWT (50 °C for 45 minutes) was tested alone and in combination with Ta SC1 application on artificially inoculated scion cuttings under practical conditions. Samples were taken directly after HWT, during the cultivation in the nursery and after uprooting.

The results showed, that HWT alone significantly reduced pathogen recovery, with complete elimination of D. seriata and significant reduction of P. chlamydospora and P. minimum shortly after treatment. Nonetheless pathogen recovery occurred over the observation period. Combined HWT and Ta SC1 application provided enhanced and durable protection, with molecular analysis confirming 90 % recovery of Ta SC1. These findings confirm that HWT alone can reduce GTD pathogen presence and integration of a Ta SC1 application offers a long-lasting approach for managing GTDs in nurseries, thereby improving high quality grapevine planting material.