BLIGHTSIM: A New Potato Late Blight Model Simulating the Response of Phytophthora infestans to Diurnal Temperature and Humidity Fluctuations in Relation to Climate Change.

Hossein A Narouei-Khandan,Ariena H.C Van Bruggen,Nicholas S Dufault,Shankar K Shakya,Karen A Garrett,Daniel Wallach,Erica M Goss,Senthold Asseng,Jorge L Andrade-Piedra

doi:10.3390/pathogens9080659

Abstract

Temperature response curves under diurnal oscillating temperatures differ from those under constant conditions for all stages of the Phytophthora infestans infection cycle on potatoes. We developed a mechanistic model (BLIGHTSIM) with an hourly time step to simulate late blight under fluctuating environmental conditions and predict late blight epidemics in potato fields. BLIGHTSIM is a modified susceptible (S), latent (L), infectious (I) and removed (R) compartmental model with hourly temperature and relative humidity as driving variables. The model was calibrated with growth chamber data covering one infection cycle and validated with field data from Ecuador. The model provided a good fit to all data sets evaluated. There was a significant interaction between average temperature and amplitude in their effects on the area under the disease progress curve (AUDPC) as predicted from growth chamber data on a single infection cycle. BLIGHTSIM can be incorporated in a potato growth model to study effects of diurnal temperature range on late blight impact under climate change scenarios.

Highlights

Potato late blight, caused by Phytophthora infestans, may be the most important plant disease worldwide since it was associated with the infamous Irish Potato Famine in the 1840s
Most simulation models consist of successive stages in the infection cycle [10,12,16,17,20,21,22,25] or spore release, survival and aerial transport [11,13,15,19]
Infected sites are divided into latent compartments: L0 is formed from infection of H by spores and turns into L1 towards the end of the latent period; the other latent compartments (L2, L3, L4, L5 and L6) originate from “lesion growth” on five successive days (See the Methods section for more details)

Summary

Introduction

Potato late blight, caused by Phytophthora infestans, may be the most important plant disease worldwide since it was associated with the infamous Irish Potato Famine in the 1840s. Pathogens 2020, 9, 659 forecasting models [2,3,4,5,6,7,8,9] as well as mechanistic simulation models [3,10,11,12,13,14,15,16,17,18,19,20,21,22], but few are focused on the potential effects of climate change [9,23]. BLITECAST [24], and are based on the accumulation of late blight risk units under daily temperature and humidity conditions summarized from hourly data [5,6,7,9,14,23]. The first and most widely used simulation model is LATEBLIGHT [12] This is a matrix model where lesions pass through 15 age classes and at the same time expand in area.

Objectives

Methods

Results