Super Science: A year of research in review
Product combos improve irrigation efficiency
By Marco Schiavon, Ph.D., and Jim Baird, Ph.D.
Using a plant growth regulator (PGR), soil surfactant and different nitrogen fertilizers can help improve water savings for bermudagrass fairways.
- Researchers tested a combination of PGRs, soil surfactants and sufficient nitrogen fertilization for water conservation on golf course fairways.
- None of the plots irrigated at 40 percent evapotranspiration (ETos) had acceptable turfgrass quality, normalized difference vegetation index (NDVI) or percent green cover comparable to those irrigated at 70 percent ETos.
- At 70 percent ETos, Primo Maxx, combined with Revolution, had the most positive effect on turfgrass quality, NDVI and percent green cover confirmed these findings.
- Except for May 2016 and 2017, bermudagrass irrigated at 70 percent ETos always provided acceptable quality.
Controlling annual bluegrass on golf course putting greens
By Aaron J. Patton, Ross C. Braun, Geoffrey P. Schortgen, Daniel V. Weisenberger, Bruce E. Branham, Bill Sharp, Matthew D. Sousek, Roch E. Gaussoin and Zachary J. Reicher

Photo 3 Study area being prepared for an application on Sept. 23, 2014. Three injured plots are evident from a late August application of Bensumec followed by early September Velocity applications. The treatment was discontinued shortly thereafter. (Photo: Daniel Weisenberger)
A recent four-year experiment evaluated individual PGR and herbicide active ingredients applied up to 12 times per year in three U.S. states (Photo 3).
- Annual bluegrass (Poa annua L.; ABG) is among the most common weeds of highly maintained turf in the United States.
- In three Midwestern U.S. states, the researchers conducted a four-year systems approach experiment to control ABG on putting greens by examining seven season-long programs of plant growth regulators, herbicides and iron sulfate fertilizer with a July or September hollow tine aerification.
- Aerification timing did not influence annual bluegrass cover at the three locations.
- Monthly applications of iron sulfate alone did not effectively control ABG.
- The effectiveness of season-long treatments varied by location, but methiozolin, paclobutrazol or bispyribac-sodium consistently reduced ABG. None completely removed annual bluegrass.