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University of Arizona
Vegetable IPM Updates Archive
Cooperative Extension
Leaf Wetness Update (Dec 12, 2018)
Upon entering the address above, you will be transferred to internet page that provides a series of tabs at the top of the page. Simply click on the tabs to access the information of interest. Some examples of the information available are provided below:


This is a new graphic for 2018/19 and provides a real time glimpse of wetness conditions for all five monitoring sites. The alert light to the right of the wetness graph turns red when temperatures drop below freezing and thus provides a warning of potential frost/ice conditions.


This graphic summarizes wetness and near surface temperature conditions for the most recent 24 hours for each monitoring location. There are two wetness sensors (red and green lines) at most locations. Dew or wetness from rain/irrigation is likely when sensor readings move into the blue, wet zone of the graphic. The warning lights turn red when sensor readings indicate wetness. Temperatures at produce height (1’ above surface) are indicated by the black line.


This graphic provides the number of hours of leaf wetness reported by the sensors at each location for the most recent 14 days. Data from both sensors are reported and data are summarized for the 24 hours ending at midnight.


All data collected at a given leaf wetness monitoring station are provided in this graphic. The top panel provides the output from the leaf wetness sensors for the past 24 hours. The second panel in the graphic provides a plot of temperature and dew point at lettuce level (1’ above surface) for the past 24 hours. Wetness typically occurs when the difference between temperature and dew point is less than 2 degrees. The final two panels (not shown) provide: 1) the relative humidity and wind speed over the past 24 hours and 2) the daily maximum, minimum and average dew point temperatures over the past 14 days.

Tab Labeled Leaf Wetness Summary Tables
These tables summarize the leaf wetness data on a daily basis and will be updated about every two weeks. On most days with wetness there are some periods when sensor output indicates a borderline wetness condition (column labeled Border). These borderline periods typically are short and often occur after sunrise when the sensors are drying. The borderline values are provided here to provide the worst-case scenario for wetness as indicated by the sensors.

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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.

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