  In this paper, we propose observers for the dynamics of anthracnose disease
described in [12]. Spatial and non spatial versions of the observers are given
following an approach similar to [12]. The models given in [12] are improved in
order to be more realistic. The conditions on parameters are more general.
There are also changes in the equations modelling the dynamics of the berry
volume (v) and the rot volume (v_r). We study theoretically the proposed
observers in terms of well-posedness and convergence. We make several
simulations to assess the effectiveness of observers which definitely display
fairly good behaviour.
