Management alternatives to control grape decline in South of Brazil

Abstract

Grape decline in Southern Brazil refers to a group of symptoms leading to plant weakening and
death. Apparently there are several causes, including ground-pearl (Eurhizococcus brasiliensis), soil fungi and other causes of plant stress. The effect of three possible alternatives of control was evaluated: pre-planting soil preparation in trenches along plant lines; chemical control of ground-pearl; and three different rootstocks (SO4, Paulsen 1103 e 043-43). The experiment was replicated in two sites where vineyards had historical problems with
plants death. The experiments were evaluated in the fourth and fifth vegetative cycles counting the number of plants with decline symptoms or dead. All three factors had a significant effect in the expression of symptoms, indicating the need of all three tested alternatives. It was observed symptoms of soil fungi attack in roots, indicating excess of soil moisture. The effect of soil trench planting system may be related to a drainage effect.