Oral Technical Session: Weather and Disease Models
44-O
A new mechanistic model to simulate effects of diurnal temperature oscillations on potato late blight development
A. H. C. VAN BRUGGEN (1), S. K. Shakya (2), H. A. Narouei Khandan (3), J. L. Andrade-Piedra (4), E. M. Goss (3), N. S. Dufault (3)
(1) Univ of Florida, Gainesville, FL, U.S.A.; (2) Oregon State University, Corvallis, OR, U.S.A.; (3) University of Florida, Gainesville, FL, U.S.A.; (4) CIP, Lima, Peru
Global climate change is associated with increased average temperatures and changes in diurnal temperature ranges. Previously, it was shown that the optimum temperature curve for the latency development rate of Phytophthora infestans (US-23) on potato leaflets (Red Lasoda) was steeper under constant (10-27°C) than under oscillating temperatures (with amplitudes of 5°C and 10°C) in a growth chamber. The optimum curves for lesion growth rate, infection efficiency and sporulation were increased under oscillating temperatures with amplitude of 5°C but decreased with amplitude of 10°C compared to constant temperatures. Using these results, a mechanistic model (BLIGHTSIM) was developed to simulate late blight under oscillating versus constant temperatures, and predict potential late blight outbreaks under climate change. BLIGHTSIM is a modified Susceptible (S), Latent (L), Infectious (I) and Removed (R) compartmental model with hourly temperature and relative humidity as input variables. Parallel box car trains were introduced in the model to simulate and limit lesion growth. The model was calibrated with data obtained from growth chamber experiments and validated with field data from Ecuador. The model provided a good fit (R2of regression of simulated on observed data) to both growth chamber and field data. BLIGHTSIM will be incorporated in a potato growth model and used to study effects of changes in average temperature and diurnal oscillations on potato late blight.