Influence of Soil Surfactants and Fungicides On Soil Moisture, Disease Presence, and Quality of ‘Champion' Ultradwarf Bermudagrass Greens.

In South Carolina, USA, ancillary observations in a fungicide efficacy trial suggested that certain fungicides influenced turf quality and localized dry spot (LDS) development, but warranted further study to quantify the relationship. Surfactants improve turf quality by promoting more uniform water distribution, and presumable more uniform water and nutrient uptake. Indirectly this would be expected to have a positive effect on plant health and disease tolerance. The objective of this experiment was to determine the relationship of commonly used surfactants and fungicides on affecting the longevity of the fungicide response, soil volumetric water content, and turf quality. During the 2008 and 2009 summers ‘Champion” ultradwarf bermudagrass was subjected to three treatments of two factors: surfactant (water control, and two surfactants), and fungicide (water control, four fungicides applied as a program, and one single chemistry). Irrigation was maintained at 75% ET with further reductions as needed to induce stressed conditions. Symptoms of two pathogens were visually determined:  Bipolaris spp. (leaf blotch) and Sclerotinia homeocarpa (dollar spot). Applying fungicides did increase turf quality and lower localized dry spot, while surfactants increased turf quality, lower localized dry spot, and increase soil volumetric water content. However, with one rating exception, there was no evidence of a surfactant and fungicide interaction to enhance quality, lower disease severity and localized dry spot, or increase soil volumetric water content.