Impacts of plant growth and architecture on pathogen processes and their consequences for epidemic behaviour A. Calonnec & J-B. Burie & M. Langlais & S. Guyader & S. Saint-Jean & I. Sache & B. Tivoli Accepted: 3 October 2012 # KNPV 2012 Abstract As any epidemic on plants is driven by the amount of susceptible tissue, and the distance between organs, any modification in the host population, whether quantitative or qualitative, can have an impact on the epidemic dynamics. In this paper we examine using examples described in the literature, the features of the host plant and the use of crop management which are likely to decrease diseases. We list the pathogen processes that can be affected by crop growth and architecture modifications and then deter- mine how we can highlight the principal ones. In most cases, a reduction in plant growth combined with an increase in plant or crop porosity reduces infection efficiency and spore dispersal. Experimental approaches in semi-controlled conditions, with con- comitant characterisation of the host, microclimate and disease, allow a better understanding and analysis of the processes impacted. Afterwards, the models able to measure and predict the effect of plant growth and architecture on epidemic behaviour are reviewed. Keywords Canopy structure . Disease transmission . Architectural traits . Microclimate . Host-pathogen models Eur J Plant Pathol DOI 10.1007/s10658-012-0111-5 A. Calonnec (*) INRA, UMR1065 SAVE Santé et Agroécologie du Vignoble, F-33883 Villenave d’Ornon, France e-mail: calonnec@bordeaux.inra.fr A. Calonnec Université de Bordeaux, ISVV, UMR SAVE, F-33883 Villenave d’Ornon, France J.-B. Burie : M. Langlais Université de Bordeaux, IMB, UMR 5251, F-33076 Bordeaux, France J.-B. Burie : M. Langlais CNRS, IMB, UMR 5251, F-33400 Talence, France S. Guyader INRA, UR1321 ASTRO Agrosystèmes tropicaux, F-97170 Petit-Bourg, Guadeloupe, France S. Saint-Jean : I. Sache AgroParisTech, UMR Environnement et Grandes Cultures, F-78850 Thiverval-Grignon, France S. Saint-Jean INRA, UMR1091 EGC, F-78850 Thiverval-Grignon, France I. Sache INRA, UR BIOGER-CCP, F-78850 Thiverval-Grignon, France B. Tivoli INRA, UMR1349 IGEPP, F-35653 Le Rheu, France