Phytomonitoring instrumentation for fine-tuning irrigation scheduling was used in a commercial avocado (Persea americana L.) orchard in Chile in 2001-2002 and 2002-2003 seasons. Soil water content, solar radiation, air and leaf temperatures, wind speed and relative humidity factors, as well as trunk, shoot and fruit growth were continuously monitored and irrigation scheduling strategies were implemented based on this information. Two main production goals were considered: yield increments and modification of fruit diameter distribution curves towards larger fruit sizes. Irrigation scheduling based on phytomonitoring information resulted in significant productivity and fruit size increments. The objective of this work is to provide a quantitative description of agronomic uses of phytomonitoring technology in fine tuning irrigation scheduling, based on actual continuously recorded field data.