control of grapevine decline with the use of drains and ridges

ABSTRACT The incidence of grapevine decline and dye back is quite severe in grapevine-growing regions of southern Brazil, especially in the Midwest of Santa Catarina State. Field studies on problematic areas identified the presence of the Brazilian ground pearl or margarodes (Eurhizococcus brasiliensis Hempel) and soil fungi (Cylindrocarpon, Fusarium and others) associated with the disease. Soil characteristics such as high clay content and poor aeration were associated with the problem. To evaluate the effect of pre-planting tillage in reducing the incidence of grapevine decline, an experiment was carried out with two rootstocks and three pre-planting tillage (regular plowing, drains, and ridges) in an area where high plant mortality had been previously observed. Pre-planting tillage with the use of ridges along the rows gave the best results with a drastic reduction in the decline incidence. The number of ground pearl cysts was unaffected by pre-planting tillage and did not relate with the incidence of decline and death of plants.