Page 22 - GreenMaster summer 2023

u FEATURE u DR. SARA STRICKER, COMMUNICATIONS & OUTREACH COORDINATOR, GTI RESEARCH BY EMILY HOWARD, JOHN WATSON, COREY FLUDE, JABER HUSINY AND DR. ERIC LYONS
PGRs:
Creeping bentgrass plots are maintained at greens height for the PGR experiment.
of Growth Marking the plots on a creeping bentgrass green in Applying PGR treatments to the turf.
advance of applying PGR treatments.
Trying to explain plant growth regulators to anyone outside of the turf
industry always gets some curious looks. “You mean you want the grass to grow LESS?” Precisely! As we know, plant growth regulators (PGRs) are applied on golf courses to control height, reduce frequency of mowing operations, and enhance playing surface consistency. The theory is that if the plant grows slower, we do not need to work as hard to maintain it.
GTI STUDY: PLANT GROWTH REGULATORS
A study at the Guelph Turfgrass Institute (GTI) in Guelph, Ontario, compared three PGR products on creeping bentgrass at greens-height (3 mm). Anuew (prohexadione-calcium), Primo Maxx (trinexapac-ethyl) and an experimental product were applied using a growing degree day (GDD) schedule and trinexepac-ethyl and the experimental product were applied on a calendar-based schedule every 4 weeks.
Growing degree days are used in agriculture to estimate the growth and development of plants over time. The concept is that growth only occurs when temperatures exceed a set threshold. In this study, the threshold temperature for turf was 0C. Each day, the average of the maximum and minimum daily temperature was calculated, and this value was added to the previous days’ average. When the total sum of the temperature averages reached approximately 300, the PGR products were applied and the GDD calculation started again from 0. Rinse, and repeat.
22 • CGSA • GreenMaster