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Fusarium head blight (FHB) in Brazil: what hav...

Fusarium head blight (FHB) in Brazil: what have we learned in 15 years?

Summary of almost 20 of research on Fusarium head blight of wheat that started during my PhD in 2000 year. I provide a historical perspective of the work organized by interests that developed over time during the establishment of my research program on the topic.

Emerson M. Del Ponte

November 17, 2020
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  1. Fusarium head blight (FHB) in Brazil: what have we learned

    in 15 years? Emerson M. Del Ponte Prof. Plant Pathology/Epidemiology
  2. FHB +rain cool +rain warm -rain hot +rain/dry hot Wheat

    Blast 90% wheat crops (5 million T) Re-emergent in Brazil
  3. My FHB research in 6 episodes A new old problem

    Knowing the enemy The chief species Food in danger Man weapons Statistical modelling Computer simulation Disease forecasting Field surveys Molecular Identification Population genetics Chemistry Immunology Pathogen biology and ecology Plant-pathogen interaction Fungicide efficacy Meta-analysis Economic analysis Failure ahead? Fungicide resistance Phenotypic and molecular 1 2 3 4 5 6
  4. Season Yield losses (%) 1984 - 1994 5.4 2000 17.5

    2001 13.4 2002 11.6 2003 26.2 2004 12.0 2005 22.2 2007 39.8 2008 23.2 2009 32.2 2010 17.8 A problem is noticed E.M. Reis R.T. Casa
  5. No-till Cumulative risk Growing season (year) Del Ponte et al.

    (2009) Climate variability effect? no till?
  6. = 4,419.5 kg ha-1 = -46.3 kg ha-1 = 2,883.6

    kg ha-1 = -46.3 kg ha-1 Damage coefficient = -1.05% pp -1 Damage coefficient = -1.60% pp -1 Estimation of damage coefficients Duffeck et al. (2020)
  7. Crop simulation (10 dates x 28 years) FHB index FHB

    risk Attainable yield Yield losses (FHB) Damage coefficient (Dc) -1.05 % 1980-1989 1990-1999 2000-2007 10.3% 10.2% 5.8% Simulations of historical yield losses Duffeck et al. (2020)
  8. FHB index Fungicide spray (1x or 2x) Probability of non-offsetting

    costs $ Actual yield (Treated) Actual yield (Nontreated) Yield diff. (kg ha-1) Are fungicides profitable? Duffeck et al. (2020)
  9. (Scoz et al 2009; Astolfi et al. 2012; Del Ponte

    et al. 2015) > 850 FGSC strains (5 years) Diverse population of species and toxin types
  10. n = 66 samples 2ppm line Del Ponte et al.

    (2012) Trichothecenes in wheat: NIV too!
  11. Species x Cultivar = P > 0.05 highly aggressive isolate

    Mendes et al. (2018) Cultivar x species effect?
  12. + 102 kg/ha Efficacy (%) Yield gain (kg/ha) Machado et

    al. (2017) Estimates of mean efficacy and yield gain
  13. Effect size Yield Return (%) Fungicidea kb D SE(D) CI

    L c CI U c P value Y CI L c CI U c PYRA + METC 70 532.08 46.40 441.14 623.02 <0.0001 17.17 14.30 20.11 TFLX + PROT 45 494.99 45.09 406.60 583.38 <0.0001 16.21 13.14 19.37 TEBU 25 448.20 54.04 342.27 554.13 <0.0001 14.68 11.24 18.22 AZOX + TEBU 25 462.43 48.92 366.53 558.32 <0.0001 14.74 11.54 18.02 TFLX + TEBU 40 468.24 42.43 385.08 551.41 <0.0001 14.66 11.92 17.46 PYRA + METC 1X 23 413.72 53.66 308.53 518.90 <0.0001 12.97 9.70 16.35 Estimates of mean efficacy and yield gain Barro et al. (2020)
  14. EC50 levels for 50 strains from RS Spolti et al.

    (2012) Sensitivity to Triazoles (TEBU and METC)
  15. EC50 levels for 35 strains R2 R1 R2 Machado et

    al. (unpublished) Sensitivity to TEBU and Carbendazim
  16. F. graminearum less sensitive to TEBU Machado et al. (unpublished)

    R2 R1 R2 F. graminearum others F. graminearum others 15-ADON 15-ADON 15-ADON Are EC50 dependent on FGSC species?
  17. 1. Previous crop not important risk factor in the subtropics

    (no-till) 2. At least two important species/chemotypes to concern 3. DON and NIV should be a target in surveys (only DON now) 4. One seems more adapted to wheat environments (F. graminearum) 5. Breeders should use the most aggressive strains Lessons learned
  18. 6. One spray of tebuconazole is a cost-effective choice (yield)

    7. Premixes (DMI+QoI) likely do not break even on costs 8. The pathogen may be adapting to fungicides - future concern? Lessons learned
  19. Key Collaborators Dr. J. Maurício Fernandes Dr. Gary Bergstrom Dr.

    Willingthon Pavan Dr. Dauri Tessmann Dr. Todd Ward Dr. Eliana Furlong Dr. Casiane Tibola Dr. Flávio Santana Dr. Lisa Vaillancourt Graduate Students (2008 - now) Paula Astolfi Piérri Spolti Paulo R. Kuhnem Jr. Camila Nicolli Gabriela Mendes Franklin Machado Maíra Duffeck Jhonatan Barro Acknowledgements