Dry conditions continued through all of December leading to low overall totals of leaf wetness as measured by the Yuma Leaf Wetness Network (see table below). The number of December days with measureable leaf wetness ranged from one day at Roll to seven days in the south Yuma Valley. No leaf wetness has been reported at any of the four monitoring stations during the first eight days of January.
The weather pattern appears to be changing and the rains occurring on 9 January may produce more leaf wetness in the coming days. Growers and PCAs can monitor data from the leaf wetness network by entering the following URL in their internet browser: http://128.196.12.122:460/
The data sets collected by the Leaf Wetness Network may also prove useful for determining areas impacted by lettuce ice. Locations with subfreezing temperatures and measureable leaf wetness are likely to have problems with lettuce ice.

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.