EFS12- Book of abstracts - Contact

SESSION 5: DISEASE CONTROL AND FORECASTING MODELS
P120 - A hierarchical bayesian approach to predict the
risk of Fusarium head blight in wheat
J. M. C. Fernandes, M. Nicolau
Embrapa Trigo, Rodovia BR 285, km 294, Passo Fundo, RS, 99001-970, Brazil 99001-970
E-mail: mauricio.fernandes@embrapa.br
Fusarium head blight (FHB) is a fungal disease of increasing concern to both yield
and grain quality. Risk modeling and prediction can be useful in disease
management and new data and statistical approaches can improve accuracy of
the predictions. Ultimately, management decisions need to be based on the
outbreak probability. Currently most approaches for risk assessment rely upon
deterministic weather-driven models based on regression techniques. After more
than a decade of development and use of a FHB decision support system across
Brazil wheat producing areas, an improvement was made taking into account the
prediction of airborne inoculum. Thus, motivating us to explore other modeling
techniques that could provide a cohesive statistical framework and formally
integrate the available information on both disease life cycle and observations.
The improved system is based on a Hierarchical Bayesian (HB) method to
estimate the probability of FHB outbreaks. Prior distributions of the estimates for
each model component were derived from previous studies using MCMC (Markov
Chain Monte Carlo) algorithms. A sample-based approach combines inference
from different crop/disease cycle processes: spore dispersal, wheat heading and
flowering, infection risk and host susceptibility. As result, predictions were
consistent with actual epidemic data both from non epidemic and epidemic years.
This study contributes with novel statistical approaches to predict FHB risk than
can integrate decision support systems to assist on FHB management.
Hierarchical Bayesian modeling is demonstrated as both a useful analytical tool
for FHB risk management and a natural investigative paradigm for developing and
focusing on the release of new wheat cultivars.
Keywords: modeling, risk assessment, decision-making
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