Quantification of landscape composition on airborne diseases using a dynamic model, application to Pseudocercospora fijiensis in Martinique

Delatouche Lucile, De Lapeyre de Bellaire Luc, Tixier Philippe, Husson Emmanuel. 2021. Quantification of landscape composition on airborne diseases using a dynamic model, application to Pseudocercospora fijiensis in Martinique. In : Landscape 2021 - Diversity for Sustainable and Resilient Agriculture - Books of abstracts. ZALF. Berlin : ZALF, Résumé, p. 178. Landscape 2021 - Diversity for Sustainable and Resilient Agriculture, Berlin, Allemagne, 20 Septembre 2021/22 Septembre 2021.

Résumé : Quantifying the effect of landscape composition on disease dynamics remains challenging because it depends on many factors: disease epidemiological traits, climatic effect, cultural practices used to control diseases and landscape features. With usual ecology modelling, it is difficult to quantify and disentangle these factors. The objective of our study was to separate landscape effect from all these other factors. To this end, we have developed a dynamic disease model that integrates disease development, climate and fungicides effects. This model was applied to the case of banana leaf streak disease (BLSD) caused by Pseudocersospora fijiensis in Martinique. This disease is one of the main biotic constraint of banana production all over the world. Each process of our model was calibrated on a dataset including 83 plots producing Cavendish banana located all over Martinique. For each plot, between 2015 and 2019 the stage of evolution of the disease (SED, represents the dynamic of fungal infection on young leaves), the types of fungicide treatment applied, and the Piche evaporation were measured weekly. The model was used in two steps. First, we ran the model for each week based on measures of previous week. Then, we established a GLM of the residues of the model as a response to the weeks after the beginning of the epidemic, the week of the year, and the Piche evaporation. This GLM aimed at taking account the effects of i) the increase of the disease pressure over the island (constantly growing since its first detection in 2011), ii) the seasonality of the disease, and iii) the inoculum potential, respectively. We then subtracted the prediction of this GLM to the simulated SED, leading to a corrected predicted SED (SEDc). We hypothesized that SEDc to be related to the landscape effect on the disease, development and sporulation because all other factors were extracted. Finally, we correlated the SEDc with landscape composition variables calculated in buffers around each plot (200, 500, 800, 1000 m). We quantified the proportion of semi-natural areas (forests), host and non-host cultivated plots, and the area of hedgerows in the 200 m buffer. Interestingly, our results show that the length of hedgerows in a 200 m buffer were negatively correlated to SEDc, i.e. it acted as constraint against BLSD spreading and development. There was also a negative effect of the proportion of cultivated banana in the landscape on SEDc (significant for all buffers), probably due to the mass effect of fungicide treatments. Surprisingly, the proportion of forest was positively correlated with the SEDc (significant for all buffers). We hypothesize that this positive effect might be the result of wild banana plants that acted as sinks of BLSD propagules in the landscape.

Agences de financement hors UE : Deutsche Forschungsgemeinschaft

Auteurs et affiliations

• Delatouche Lucile, CIRAD-PERSYST-UPR GECO (FRA) ORCID: 0000-0002-1309-7986
• De Lapeyre de Bellaire Luc, CIRAD-PERSYST-UPR GECO (FRA) ORCID: 0000-0003-1243-0887
• Tixier Philippe, CIRAD-PERSYST-UPR GECO (FRA) ORCID: 0000-0001-5147-9777
• Husson Emmanuel, SICA-CERCOBAN (MTQ)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/603289/)

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