Trichoderma atroviride SC1 can prevent infections of Phaeoacremonium and Phaeomoniella in nurseries

Transcription

1 Trichoderma atroviride SC1 can prevent infections of Phaeoacremonium and Phaeomoniella in nurseries Ilaria Pertot 1, Luca Pasini 1, Daniele Prodorutti 1, Andrea Nesler 1,2 Fondazione Edmund Mach 1, BiPA 2

2 Brief overview of the epidemiology of the tracheomycosis Infections: pathogens conidia released during the growing season colonize pruning wounds Most of the infections take place in the vineyards, however in many cases plants are already infected at the time of planting Risk of infections in the propagation process in the nurseries Infections from mother plants (mainly rootstock, relevance of the scion is still debated) Nursery Mother plants Vineyard

3 High risk of infection by Phaeomoniella chlamydospora and Phaeoacremonium minimum (syn. P. aleophilum) during plant propagation in nurseries (conidia found in water, tanks, tools, substrate, soil, etc.) MOTHER PLANTS Rootstocks - Scions HYDRATION Rootstocks - Scions GRAFTING CALLUSING ROOTING FIELD Infected plants Conidia in the water Conidia in the Conidia in the Conidia in water substrate the water Conidia in the environment

4 Options to control infections in the nurseries The most promising treatment in the propagation process: hot water over 5 C (Gramaje et al. 29) On some varieties it negatively affect the quality of plants, in some contexts is not practicable Chemicals: not available (not registered, not effective) Trichoderma spp.: effective in protecting pruning wounds in the vineyard against the pathogens (Di Marco et al., 2; Fourie et al., 21; Fourie and Halleen, 26) Trichoderma spp.: effective in protecting plant in nurseries (Fourie et al., 21; Hunt et al., 21; Di Marco et al., 22; 24; Fourie and Halleen, 24; 26; Veronesi et al., 26; Di Marco and Osti 27)

5 Trichoderma species/strain: how relevant is? Very important for the treatments of the pruning wounds Also important in the nursery treatment Fast germination and growth rate (efficient and fast colonization) High competition at the colonization site (successful and stable colonization) Temperature range (persistent colonization, especially at high T C) Endophytic habit (not yet confirmed) The strain must persist until the end of the season (full-year protection)

6 Trichoderma atroviride SC1 Result of a screening process (started in 24) based on: Good technological properties (fast growth and conidiation, high conidia harvest in fermentation) Germination and colonization a low T C (applied in winter) Good, fast and persistent colonization of wood (isolated from hazelnut dead wood) High growth rate and competition (niche exclusion for pathogens and other MOs) Production of lytic enzymes and toxins (good biocontrol activity)

7 January February March April May Protocol: Application of T. atroviride SC1: 4 times in nursery 1 st Application 2 nd Application 3 rd Application 4 th Application Vintec (Belchim; 2 x 1 1 conidia g -1 formulated product) at 2 g l -1 Artificial infection (after grafting) Trials repeated, data pooled Hydratation prestorage Hydratation pre-grafting Grafted cuttings Stratification in sawdust Rooting Planting Material collection Cold storage Grafting Waxing Forcing Rooting

8 Infected plants (%) Efficacy against Pal and Pch Standard treatment (8- hydroxyquinoline sulphate, Cryptonol), many growers still use it Treatment in T1, T2, T3, T4 with T. atroviride SC1 (water or sawdust) Assessment of Pal and Pch (microbiological, with a subsample with PCR for validation) at the grafting union (no infections at the root side) b b a Pal Pch Pal Pch Pal Pch Standard T. atroviride SC1 Untreated Kruskal Wallis test: v2 = 29.47; df = 5; p<.1; multiple bilateral comparison at p<.1 Although not significant, an increasing trend of infections was observed with hydroxyquinoline sulphate: tissue damages, reduction of natural biocontrol can be hypothesized to explain this slight increase a b b

9 Infeced plants (%) What is the most effective treatment? Pal Pch c c b a a Untreated T1 T2 T3 T c bc ab a a Untreated T1 T2 T3 T4 Hydration before cold storage (T1) and hydration before grafting (T2) are the most effective (treatment of sawdust and at rooting, T3, T4 are less effective) At each time point new wounds are created the full program may contribute to a safer protection (ANOVA Pal: F = 65.3; df = 4, 48; p<.1; ANOVA Pch: F = 16.33; df = 4, 35; p><.1; Tukey s test at a =.5)

10 UNT-Pal UNT-Pch T1-Pal T1-Pch T2-Pal T3-Pch T3-Pal T3-Pch T4-Pal T4-Pch Trichoderma spp. colonizatiuon (%) T. atroviride SC1 colonization 12 1 c c c c b 2 ab b ab a a Better colonization at T1 and T2 Relation between colonization and efficacy (regression significant, p<.1) (ANOVA: F = 71.3; df = 9, 3; p<.1; Tukey s test at a =.5)

11 T. atriviride SC1 olonization (%) Effect of water temperature At 2 g/l Viability >8% 1 and 15 C Always optimal colonization of grafting point (at planting time) Pal Pch Pal Pch 1 C 15 C 1 C 15 C Untreated

12 Shhot lenght (cm) Diameter of the middel internode (cm) Growth promotion? 14, ab ab b a e d c b b ab,8,7,6,5,4,3,2,1 ab ab bc a e d c bc bc ab Pch Pal Pch Pal Pch Pal Pch Pal Pch Pal Pch Pal Pch Pal Pch Pal Pch Pal Pch Pal Untreated T1 T2 T3 T4 Untreated T1 T2 T3 T4 T. atroviride SC1 was not selected as growth promoter (main action as biocontrol agent), however the treatment in T2 improves the quality of the plants (ANOVA shoot length: F = ; df 9, 3; p\.1; ANOVA diameter: F = 7.29; df = 9, 3; p\.1; Tukey s test at a =.5)

13 Practical questions from growers Recommendation: to prepare the water suspension just before use Can I prepare the suspension in advance? What is the risk of keeping the suspension for some time before treatment? Recommendation: not to reuse the suspension Can I reuse the suspension? Is the conidia concentration/viability reduced with the reuse of the suspension?

14 Conidia viability (% to T) Viability of conidia in the suspension Preparation of the suspension in advance is not recommended: however it may happen in the practice Good survival until 72 h if the suspension is prepared in distilled water and kept from 5 to 15 C h 48h 72h 24h 48h 72h 24h 48h 72h 5 C 5 C 5 C 1 C 1 C 1 C 15 C 15 C 15 C Neither temperature (F =.27; df = 2, 27; p =.76) nor time (F =.11; df = 2, 27; p =.89) nor temperature 9 time (F =.35; df = 4, 27; p =.84) are significant at the two-way ANOVA.

15 Conidia viability (% to T) Recycling the suspension Recycling of the suspension is not recommended: however in some nurseries growers soak plant material in the same suspension (suspension cannot be discarded each time) Good survival until 72 h if the suspension is prepared in distilled water and kept from 5 to 15 C h 24h 38h 48h 14h 24h 38h 48h 1 C 1 C 1 C 1 C 15 C 15 C 15 C 15 C (ANOVA F = 1.57; df = 9, 3; p =.17).

16 Nursery: efficacy trials GEP trials (dossier for registration) 14 trials DE, FR, IT, ES, HU 36 set of data GEP and DEMO (FR) Courtesy of BiPA/Belchim

17 Coloniazation (%) Colonization Efficacy trials in FR, metaanalysis (T. atroviride SC1 treated plants, n=18) Very high colonization by SC1 No presence of Pal and Pch (efficacy = 1%) Some presence of Botryosphaeriaceae (no distinction between pathogen and saprophytic) SC1 PAL PCH BO Courtesy of BiPA/Belchim

18 Pal presence (%) Pch presence (%) Colonization and efficacy Trichiderma spp. colonization (%) Meta-analysis of colonization by SC1 and PAL or PCH in efficacy trials (treated and untreated, n=36), loss of control below 2% of SC1 colonization at the end of the season Trichoderma spp. colonization (%) Courtesy of BiPA/Belchim

19 Conclusions Treatments with T. atroviride SC1 in the propagation process in nurseries con prevent colonization of Pal and Pch (and most probably Bot) Colonization efficiency by Trichoderma spp. is crucial to achieve efficacy T. atroviride SC1: robust strain (flexibility in the treatment conditions), fast colonizer, good competitor at the site of infections Can only prevent infections in the plant propagation (healthy mother plants are crucial)

20 Thank you for your attention!