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Temik (aldicarb) is a nematicide that has been used widely in the Florida citrus industry as nematodes significantly reduce tree vigor, growth, and fruit productivity. However, concerns about groundwater contamination have led to regulations requiring a 91.4 m (300 ft) buffer around all potable water wells and a 304.8 m (1000 ft) buffer for wells in highly vulnerable soils. To provide documentation of proper application, two DGPS-based approaches were considered for implementation on current pneumatic dry granular applicator units. The first was a black-box DGPS/system status data logger. A second level system was developed for data logging and control through a hand-held pocket PC using Farmworks variable rate technology (VRT) software. Electronic sensors, interfacing, and signal conditioning were incorporated into a pneumatic discharge granular applicator unit to demonstrate these technologies for both ground wheel driven and PWM (pulse width modulation) motor-based dispensing. The DGPS unit used for both applications was a wide area augmentation system (WAAS) corrected Trimble 106 antenna. Additional sensors were implemented for measuring material discharge rates and ground speed for PWM control. Performance data, logged at 1 Hz for both systems and a general error analysis, are presented. Factors, such as well-spotting accuracy and product delivery times, are included.