Crop protection and, more generally food safety, has become a major concern in many countries around the world, and in particular in Southern countries. In the past, many field experiments were conducted to develop and test new technics, new crop varieties, or new control methods. Now, this is almost impossible. Like in other industries, like the car or space industries, only focused experiments are allowed, that are supposed to provide sufficient informations or data to make appropriate choices. In general, this is because these experiments are often expansive, difficult to conduct, and/or to reproduce. That is why Modelling, and in particular Mathematical Modelling, Mathematical Analysis, and Numerical Simulations are more than needed as a complementary approach, in order to be able to select the most important traits or variables, as well as the relevant field experiments to conduct in order to obtain valuable data for the Model and also to improve our knowledge. In this talk, I will present several applications of Mathematics in crop protection, including plant vector-borne diseases, plant bioagressors.... In particular I would like to emphasize the importance of joined collaborations between modellers and field experts, leading not only to novel and original experiments but also to novel, original, and challenging mathematical problems, from the theoretical and numerical point of view... with, in addition, pratical applications. (Texte intégral)