Effects of Trinexapac-Ethyl and Daconil Action (Acibenzolar-S-Methyl and Chlorothalonil) on Heat and Drought Tolerance of Creeping Bentgrass

The plant growth regulator trinexapac-ethyl (TE) is known for its effects of suppressing shoot vertical growth. Some fungicides are claimed to promote the physiological health of plants in the absence of diseases. The objective of this study was to determine whether acibenzolar-S-methyl (one of the active ingredients in Daconil Action), TE alone, or the combination of the two may be most effective in promoting creeping bentgrass (Agrostis stolonifera L.) tolerance to heat and drought stress under field conditions. Daconil Action and TE were foliar applied alone or in combination to creeping bentgrass managed under fairway conditions at Rutgers University in 2014 and 2015. Stress tolerance was measured by evaluating turf quality, leaf membrane stability, relative water content, and canopy characteristics estimated by multispectral radiometry. Foliar application of either Daconil Action or TE alone improved heat and drought tolerance, and the positive effects were more pronounced and consistent during the stress periods with the combined treatment than either treatment alone. The beneficial effects of these compounds were most pronounced during periods of drought or heat when stress induced the most severe physiological damages. Foliar application of these compounds may help creeping bentgrass maintain better quality turf during hot or dry periods in warm climate conditions with limited water resources for irrigation.