Organosilicone surfactants were effective in reducing fairy ring in experiments conducted in Edmonton. There was, however some indication that these compounds could injure healthy turf. In 1994 and 1995, further testing was done to determine if: 1) the organosilicone, Sylgard, could help control fairy ring on a golf course, 2) high pressure injection together with reduced levels of surfactant, would give control of the disease without grass injury and, 3) heavy watering following surfactant application would increase surfactant efficacy.
Materials and Methods
In 1994, seven ‘blocks’ of rings were selected at the Carstairs Golf Club. Each ‘block’ consisted of six rings which were of approximately equal severity. Each of the six different treatments was applied to a 1.22 m by 2.0 m area such that the arc of the ring was roughly in the centre of the treated area. The six treatments were as follows: 1) application of 23.5 L/m2 of Sylgard at a concentration of 0.22%, 2) injection of 6 L/m2 of surfactant at a concentration of 0.22%, with a Rogers liquid pulse injector (Rogers Innovative Inc., Saskatoon), 3) application of surfactant with both injection and drench, 4) drenching with the equivalent amount of water without surfactant, 5) injecting with the equivalent amount of water without surfactant and, 6) drenching and injecting with water.
In 1995, three levels of surfactant treatment were tested at the golf course: application of no surfactant, two surfactant applications and four surfactant applications. For each of these three basic treatments, supplemental watering was either provided at the rate of 1.5" per week, or not provided, thus producing a total of six treatments. The treatments were applied to four ‘blocks’ of rings. Thatch depth, mycelium development, turf health and soil moisture content were measured.
Results and Discussion
Throughout the summer of 1994, sampling was done from the rings and from healthy, treated areas outside of the rings to determine soil water content, amounts of fungal mycelium, and turf condition. There was no evidence that the surfactant had injured the grass. On the other hand, there was no evidence that any of the surfactant treatments were more beneficial than water.
As in the previous year 1995 results presented neither injury to the grass nor any apparent benefit from the surfactant.
The contradictory results between experiments done in Edmonton and those done at the golf course may have resulted from the difference in the turf at the two locations. At the golf course the grass was dense and well maintained and there was considerable thatch. The turf in the Edmonton experiments was less dense and subjected to only minimum maintenance. Thatch was not measured in Edmonton, but may well have been thinner than at the golf course. Laboratory experiments suggest that organosilicone surfactants mat be bound by organic matter. At the golf course, it is possible that most of the surfactant was bound, not in the soil solution, and thus less effective. If this is the case, then organosilicone surfactants may prove to be more effective on home owner’s lawns than on golf courses.
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