The yellow spoon leaf disease (or TYLCV) continues to inflict losses on tomatoes from time to time in the Souss Massa plain. The appearance of this epidemic is attributed to the introduction of new strains of the virus and to the appearance of new biotypes of its vector Bemisia tabaci described as resistant, with higher reproductive potential and rapid transmission capacity. This book presents a bioecological study that has allowed to periodically monitor the evolution of the virus symptoms and the populations of B. tabaci in the larval and imaginal state, adapting rapid and efficient control and detection techniques. The results of such a study alone do not allow to fight effectively against this disease and its vector if other aspects are not taken into account to better control the system of prevention and integrated protection. The measures towards which the producers of the region have turned (Prophylactic, biological, chemical, introduction of new tolerant varieties, development of barriers...) have at least allowed to master an adequate control system.