Research on the effects of some treatments to dormant grapevine canes for endophytic fungal flora and Neofusicoccum parvum control

In this study, it was aimed to investigate probable eradicative effects of pre-heated fungicide suspensions and hot-water treatments on latent infections of Neofusicoccum parvum and other endophytic fungi. To determine endophytic fungal flora, standard mycological isolations were done from dormant grapevine (Vitis vinifera cv. Prima) cuttings (obtained from Manisa, Tokat and Tarsus) and fungal species were identified with classic and molecular methods. To assess efficacy of the treatments, infected grapevine cuttings were subjected to hot-water treatments (30°C-12 h, 35°C-6 h, 40°C-2 h, 50-53°C 30 min) and heated fungicide suspensions (cyprodinil + fludioxonil, tebuconazole ve thiophanate-methyl; 30°C-12 h 35°C-6 h, 40°C-2 h and 50°C-30 min) and pathogen was re-isolated from the inoculation points. Pre-heated fungicide suspensions at 50°C and below (especially 40°C-2h tebuconazole), were able to reduce N. parvum infections maximum by 34.3% but non-fungicide suspensions (at those temperatures) could not show any effect. When water temperature increased, the curative effect of cyprodinil + fludioxonil and thiophanate-methyl reduced but tebuconazole was not affected. Meanwhile, these treatments reduced the presence of endophytic species (except Acremonium sp.). According to the results, it was concluded that the treatment of tebuconazole at 40 °C for 2 hours is a reasonable application to produce healthy plants for grapevine nursery.