The Evaluation of Continuous Thermistor-based Leaf Temperature Measurements and an Indicator of Vine Water Status in Irrigated Winegrapes

Significant differences in leaf temperature relative to ambient air temperature were discernable for winegrapes under four different levels of irrigation stress. Greater differences in canopy temperature were discernable in the morning as compared to the afternoon, when no significant differences were seen. The method employed uses inexpensive thermistors (temperature sensors), which are placed in direct contact with the underside of leaves; each thermistor is read automatically every 15 minutes with a datalogger, allowing measurements to be taken over the summer season with minimal effort. The equipment has been deployed for two summers with no failures.