3/13/2017 - By Dr. Raymond Snyder

Much to the chagrin of early rising mower operators, turf managers often want to suppress the formation of morning dew.  For example, reducing dew formation and the length of time dew persists can reduce disease incidence in certain cases.

Dew suppression can be achieved either manually or by using surfactants.  While the manual method is pretty straight forward, with numerous types of surfactants existing, one needs to decide which to choose.

A study was initiated at the University of Florida on ultradwarf bermudagrass to evaluate several surfactants at specific rates to determine their effect on the visual appearance of morning dew.  In this study, five variants of surfactants were utilized:

1. Penetrant wetting agent (5 oz/1000 sq ft)
2. Siloxane-type surfactant (8 oz/acre)
3. Nonionic spreader sticker (8 oz/acre)
4. Activator-type surfactant (8 oz/acre)
5. Injectable-type surfactant (1 oz/1000 sq ft)

Each surfactant was applied within the label range.  In addition, an untreated control was utilized. Dew was rated on a scale of 0-3 with 0 denoting no dew and 3 as greatest amount of dew.

The effectiveness of controlling dew formation varied based each surfactant type (see chart below).  One day after application, the best performers were the penetrant wetting agent, injectable-type surfactant, and the siloxane-type surfactant.  From two to four days after application, the penetrant wetting agent outperformed the other surfactants.

Based on this study, one should consider using a penetrant wetting agent for maximum dew control for periods greater than one day after application.  Other surfactants, such as the siloxane surfactant can reduce dew formation effectively, but may require application at the high end of the recommended use rates (i.e. greater than 8 oz/acre) to increase dew suppression longevity.

Effect of surfactants on the visual appearance of morning dew on ultradwarf bermudagrass

University of Florida-Fort Lauderdale

One day after application

Four days after application