COURSE CARE
Update From The UC Riverside Turfgrass Field Day October 14, 2012 By Pat Gross

In the salinity study at UC Riverside, plots receiving high-saline water at an ETo of 80 percent did not survive. Additional tests will be performed to gain a better understanding of plant-soil-microbial interactions under stress conditions.

More than 200 turf professionals throughout California attended the UC Riverside Turfgrass Field Day on September 13th. The amount of research activity continues to increase every year at UC Riverside, and Dr. Jim Baird and his graduate students have several interesting projects in progress. The tour included 11 stops that detailed various research projects ranging from salinity management, disease control and kikuyugrass management. The following are a few highlights from the field day:

Leaching requirements for turfgrass salinity management and water conservation

This study was initiated in 2011 to test various irrigation regimes using high-saline water (4.2 dS/m). The treatments include water applications at 140, 120, 100 and 80 percent of potential evapotranspiration (ETo) on perennial ryegrass test plots. The goal is to see how much leaching is actually necessary under field conditions to maintain acceptable turf quality. Although turf quality was good during the first six months of the study, all plots showed some degree of turf loss over the next six months, with no living turf in the plot receiving 80 percent ETo. Plots receiving 100 to 120 percent ETo had turf loss ranging from 10 to 20 percent and the plots remained functional, i.e., the soil was not excessively wet to preclude routine mowing. Additional tests will be performed as part of this project to gain a better understanding of plant-soil-microbial interactions under stress conditions and further study how plants are able to adapt to salinity and drought.

Management of anthracnose on annual bluegrass

Thirty-five different fungicide treatment protocols were tested for the control of anthracnose on annual bluegrass maintained at teeing ground height. Nine of the treatments resulted in less than 5 percent disease cover through the entire study. Phytotoxicity tended to occur with applications of DMI fungicides, which is common when such products are applied under conditions of summer stress. During the study, test plots also became infected with summer patch and dollar spot, which provided an opportunity to see if treatments were effective on those diseases as well. The overall best turf quality was observed on plots treated with difenoconazole + azoxystrobin (Briskway™) and chlorothalonil + acibenzolar (Daconil Action™). Other treatment programs that were effective included a rotation of chlorothalonil, QoI and DMI fungicides.

Optimal management practices for kikuyugrass quality and playing conditions

It is especially good to see that UC Riverside is performing studies on kikuyugrass given the fact that it is the primary turf species at many golf courses, parks and home lawns from the Central Coast through Southern California. Treatments tested included mowing frequency, vertical mowing, grooming, nitrogen rate and applications of trinexapac-ethyl (Primo Maxx®). Biweekly applications of trinexapac-ethyl reduced mower scalping and improved turf quality, color and ball roll. Although initially disruptive, deep vertical mowing resulted in improved color, turf quality, less mower scalping and better tensile strength compared to grooming.

Complete details and copies of research reports are available at the UC Riverside Field Day 2012.

Please do not hesitate to contact Mr. Pat Gross: pgross@usga.org or Mr. Brian Whitlark: bwhitlark@usga.org, or call the Southwest regional office at (714) 542-5766.