Wednesday, November 15, 2006 - 2:40 PM

GCSAA/USGA Wetting Agent Evaluation.

Clark Throssell, Golf Course Super. Assoc. of Amer., GCSAA, 1550 Country Manor Blvd. #224A, Billings, MT 59102

Wetting agents are widely used by golf course superintendents across the country to manage localized dry spots (LDS) on putting greens. Superintendents have expressed a strong desire for product comparison data to make informed use and purchasing decisions. There has been limited side-by-side comparison of wetting agents in university trials. The Golf Course Superintendents Association of America and the United States Golf Association cooperated on this evaluation of wetting agents with the goal of providing unbiased information on the 10 wetting agents most commonly used by superintendents. The specific research objective was to determine the effectiveness of the wetting agents to control LDS on putting greens. Scientists at each of nine locations followed a common protocol to conduct the evaluation. Wetting agents were applied at the highest label rate for control of LDS and only liquid formulations were evaluated. Data on turf color, turf quality, phytotoxicity and degree of soil hydrophobicity were collected at regular intervals throughout the study. The evaluation was conducted over a four-month period when stress from LDS was most severe in both 2003 and 2004. Results for each evaluation site were analyzed separately. Due to abnormally cool weather, abundant rainfall or both, stress from LDS was not detected at three of the nine evaluation sites. At the six sites that experienced stress from LDS, seven of the wetting agents reduced soil hydrophobicity as measured by the water droplet penetration test. The specific rankings of wetting agents in reducing soil hydrophobicity varied by location. Phytotoxicity damage varied due to wetting agent and location. Turfgrass quality and color ratings mirrored each other and in most cases were improved by the application of wetting agents. Golf course superintendents can use these results to make better informed decisions when purchasing and using wetting agents.