Abstract

Years of research into the use of chemical intervention for the maintenance of quality in stressed turfgrass often induced by the combination of low mowing heights, suboptimal fertility, high summer heat, and inadequate water availability has led to the discovery of the beneficial properties of certain molecules. When combined, such chemistries provide protection against abiotic stress and allow turfgrass to withstand or recover faster after stressful periods. With the success of these discoveries has come the need to provide quantitative evidence to the regulatory authorities to document the benefits of novel compositions to provide turf managers with tools to assist them in dealing with stressed turf.

Methods have been introduced over the last years to quantify the performance of turf under stress. Techniques to measure photosynthesis, photochemical efficiency, and root function have primarily been employed either in a greenhouse or a lab setting and are used to describe the turfgrass’ performance under one type of stressor. In-field measurement of gas exchange has been successfully employed but requires long periods of experimentation under constant conditions and is not conducive to the fast characterization of chemistries that can be employed to intervene in the stress cycle. One non-invasive technique, red and near infrared radiometry has been studied by university and industry scientists alike and this can be used to characterize and quantify stress differences in both fine cut and long cut turfgrass. This has greatly improved the ability to identify novel compositions of stress alleviating chemistries.

Results for novel compositions based on QoI type fungicides such as trifloxystrobin with DMI classes fungicides or a dicarboximide such iprodione applied to turf at rates determined for the prevention of biotic stress also provide the plant with greater ability to withstand the rigours of summer and winter extremes. The use of a fosetyl-AL composition as a preventive treatment for summer decline has been well established in the tool box of the turf manager. For some the underlying mechanisms were not well understood. Results show effectiveness in reducing harmful or excess radiation. Experiments using photochemical methods through fluorescence detection, novel techniques in cuticular transpiration analysis, N¹⁵ uptake to quantify root function, in-field carbon flux measurements and spectral radiometry have characterized both the turfgrass’ reaction and the performance of the compositions to alleviate environmentally induced oxidative stress. The opportunity has arisen, having understood the underlying mechanism of fungicide compositions in alleviating oxidative stress, to introduce new non-pesticide products that address symptoms of transient drought or turf robustness due to lack of available water by acting on the plant rather than just the soil. In conclusion the integration of soil and plant management programmes will lead to a less stressful time for the turf manager.

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