Our team develops a programme of epidemiology to define the characteristics of the plant and of the crop canopy which are able to modify the pathogen and to influence quantitatively and qualitatively, the spatio-temporal development of the disease and of the epidemic. The plant, with its level of resistance, but also with other genotypic characteristics and with its phenotypic characteristics, constitutes a factor on which it is possible to act to modify the disease progress. Moreover, at the plot level, the crop canopy, mainly with its architecture, influences the epidemiological disease development.
To develop this topic, two pea diseases are studied : ascochyta blight (fungi complex Mycosphaerella pinodes, Phoma medicaginis var pinodella) and Aphanomyces root rot (Aphanomyces euteiches). Pea pplant is characterized by an indeterminate vegetative system of which all organs present symptoms, and a root system with nodules for the symbiotic fixation nitrogen which can be modified by the diseases.

Our activities are organised around tree questions :

1) How the plant and crop canopy characteristics are able to modify the pathogen?
The objective is to determinate how the plant can modify the primary and secondary inoculum. Quantitative aspects (primary inoculum survival) and qualitative aspects (sptatio-temporal repartition of the pathogens, intra and interspecific characterisation of the pathogens populations) are studied.

2) How the plant and crop canopy characteristics are able to modify the disease?
Disease depends on the development of one or several disease cycles. The role of partial resistance on the steps of this cycle and the effect of crop canopy on symptoms are studied.

3) How the plant and crop canopy characteristics are able to modify the epidemy?
Epidemic is characterised by the spread of the disease on a great number of plants. We study the different factors, mainly architecture, which modify the appearance of the first symptoms and the rate of disease extension of epidemic.