The past two weeks have produced the coldest temperatures of the year. Sub-freezing, near-surface temperatures have been recorded on numerous occasions at all four monitoring stations (Table 1). Leaf wetness has been quite variable across Yuma County over the past two weeks, ranging from one night at Roll and North Gila to eight at South Valley (Table 1). On most nights the number of hours of wetness has been low with only a few nights producing in excess of six hours.

Growers and PCAs can monitor data from the Yuma Leaf Wetness Network through the AZMET website located at the following URL: http://128.196.12.122:460/

The website updates information on leaf wetness and near-surface air temperature every 15 minutes. Wetness data are provided in graphical format (see figure below). Output from the leaf wetness sensors increase from the grey (dry) zone of the graph to the blue (wet) zone when wetness (dew or rain) is detected by the sensors.

To contact Paul Brown go to: pbwown@ag.arizona.edu.

For questions or comments on any of the topics please contact Marco Pena at the Yuma Agricultural Center.
College of Agriculture, The University of Arizona, Tucson, AZ.