One of the key issues in crop protection products to be applied in tree crops is the dose rate adjustment. An inappropriate dose selection could be responsible of the lack of efficacy due to under dosage and a loss in efficiency due to over dosage. Both situations imply economical losses and greater impacts on the environment. A better dose adjustment is possible from a variable rate technology approach by measuring the crown volume and adjusting the dose rate on-the-go according to the variation of the estimated vegetation volume. Tests have been done with a variable rate sprayer prototype and satisfactory results have been achieved.