Abstract Detail

Horticulture

Fall, M. L. [1], Van Der Heyden, Hervé [2], Carisse, Odile [3].

A quantitative dynamic simulation of Bremia lactucae airborne conidia concentration above the lettuce canopy.

Lettuce (Lactuca sativa L.) downy mildew, caused by the oomycete Bremia lactucae Regel, is a major threat to lettuce production worldwide. Lettuce downy mildew is a polycyclic disease driven by airborne spores. A weather-based dynamic simulation model for airborne spores was developed to simulate the aerobiological characteristics of the pathogen. The model was built using the STELLA platform by following the system dynamics methodology. The model was developed using published equations describing sub-processes (e.g., sporulation) and assembled knowledge of the interactions among pathogen, host, and weather. The model was evaluated with four years of data by comparing model simulations with observations of hourly and daily airborne spore concentrations. The results showed accurate simulations of the trend and shape of airborne spore dynamics. More than 95% of the time, the daily simulated airborne conidia concentration was 0 when airborne conidia were not observed. Also, the relationship between the simulated and the observed airborne spores was linear. In more than 95% of the simulation runs, the proportion of the linear variation in the observed values explained by the variation in the simulated values was greater than 0.7 in all years except one. Most of the errors came from the deviation from the 1:1 line, and the proportion of errors due to the model bias was low. This model is one of the few dynamic models developed to mimic the dynamics of airborne inoculum and represents an initial step towards improved lettuce downy mildew forecasting and management.

1 - University of Sherbrooke, Biology Department, 2500 De l’Université Blvd.,, Sherbrooke, QC, J1K 2R1, Canada
2 - Compagnie de Recherche Phytodata inc., 111 Rang Saint-Patrice, Sherrington, QC, J0L 2N0, Canada
3 - Agriculture and AgriFood Canada, 430 Gouin Bvl, St-Jean-Richelieu, Qc, J3B 3E6, Canada

Keywords:
simulation model
decision support system
Disease management.

Presentation Type: Oral Paper:Papers for Topics
Session: 23
Location: Salon 19/20/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 4:30 PM
Number: 23004
Abstract ID:359
Candidate for Awards:None