Dry weather has remained in place for the past two weeks, resulting in low humidity levels and limited levels of leaf wetness. No leaf wetness was recorded at the Roll and the YAC monitoring sites during this period while several short periods of wetness were observed at the North Gila site (Table 1). Higher levels of leaf wetness, ranging from 3.9 to 6.4 hours/day, have been recorded at the South valley site during the past four days and may warrant an uptick in disease monitoring (Table 1).

Temperatures near ground level (Table 1) have generally remained above freezing during the past two weeks. Exceptions (sub-freezing near surface temperatures) have been reported at Roll (24, 25 & 27 January), YAC (25 January) and South (27 January). Medium term forecast models suggest a trough of low pressure will impact the Yuma area Sunday through Tuesday, producing windy and cooler weather with a slight chance for precipitation.

Growers and PCAs can monitor data from the Yuma Leaf Wetness Network through the AZMET website located at the following URL: https://ag.arizona.edu/azmet
Click on the button labeled Crop Reports, then click on the button labeled Yuma Leaf Wetness Network. Access to Network data may also be achieved by entering the following numeric URL address: http://128.196.12.122:460/

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.