The goal of this research was to use recent advances in the global positioning system and computer technology to apply just the right amount of fumigant where it is most needed (i.e., in the neighborhood of each tree planting site or tree- planting-site-specific application) to decrease the incidence of replant disease, and achieve the environmental and economical benefits of reducing the application of these toxic chemicals. In the first year of this study we retrofitted a chemical applicator with a high-performance global positioning system receiver (accuracy in the range of 10 to 20 cm), an embedded controller to read GPS data and control a solenoid valve to implement tree-planting-site-specific fumigant application. Although the system worked well, the results of accuracy tests indicated that the RMS error in position location was 33.5 cm, which was more than desirable. To improve the position location accuracy, a new system was developed during the second year of this study. In this system, the embedded controller which was slow to perform all the necessary computations in real-time was replaced with a higher speed controller and used a Pulse Width Module (PWM) and solenoid actuated nozzles to provide precision rate on demand. Extensive testing indicated that the new system had a RMS error of less than 15 cm. The system was field tested in three almond orchards in California during Fall 2007. The system performed well in all three locations.