Wet! Saturated Soils, New Yellow Ring Disease, Broadleaf Weeds, and Moss Research
May has gone backwards. Cool, overly wet conditions were enjoyed during the month’s first full week?! To be truthful, this back and forth is normal and typical of most springs. However, the overall weather pattern this spring has been dominated by frequent rain events. Very different compared a year ago when large portions of the Midwest were experiencing a severe drought lasting until late June. When soils are dry, golfers enjoy firmer surfaces and improved playability. Dry conditions also provide golf course superintendents something good — relief from addressing chronic fungal diseases and chasing common weeds. Flash forward to 2024 and one issue has jumped ahead of the rest. Yes, broadleaf weeds have definitely taken the lead.
On golf courses this week, conditions were soft except on sand-based greens; as constructed they remain firm/fine. The culumlation of recent rains were impactful to our predominantly clay native soils. Saturated! But why do periods of wet weather always seem so amplified on golf courses? By design, most are built to take on large rain events and store it. Any excess is then rerouted to local waterways — ponds, lakes, rivers, streams. Just one of the environmental benefits courtesy of golf that most are unaware, but enjoy. “Golf courses can help manage stormwater runoff, aiding in flood prevention. They also recharge groundwater supplies and filter surface runoff.” For more see USGA’s recent article The Environmental Benefits of Golf Courses. And in the landscape? For the first time all of our native oaks or Quercus species have leaves. Meanwhile, a non-native tree, horse chestnut or Aesculus hippocastanum, suddenly became much more noticeable via large clusters of white flowers. It’s a lush, green spring that’s moving two steps forward and one step back. So get out. Enjoy the outdoors. And watch your step?
Weather
Scouting for Broadleaf Weeds? Canada Thistle or Creeping Thistle (Cirsium arvense)
This week it became obvious that now is the time for herbicide spot treatments to address broadleaf weeds. Plants are still in the juvenile state and much easier to control. One of our difficult-to-control weeds we just call “Thistle”. Known as creeping thistle or Canada thistle in the United States it has dual abilities to reproduce itself. That can happen by seed as well as by underground plant parts that also allow for its spread.
“Field Thistle” is the nemesis of many a farmer (insert my Iowa grandparents here). It also represents a difficult weed for golf course superintendents especially in areas where maintenance by mowing is restricted. Not surprisingly, out-of-play native areas are hit the hardest. Filled with unmown grasses like fine fescues or with a mixture of grasses and native flowers like common milkweed. These native areas are beautiful natural habitats to be sure, but such areas are not without inputs — weed control primarily.
Scouting for Disease — New Disease Yellow Ring
A second report within a month period of a new yellow ring disease. Appears to impact greens that are predominately Poa annua. Cool, wet conditions were associated with both outbreaks. Soil temperatures at a 2 inch depth have ranged between 55 and 65 degrees during the time period.
What you should know about “Yellow Ring”
- Symptoms are identical to Waitea Patch — bright yellow rings on greens
- “Yellow Ring” is a new disease and is more difficult to control — exact fungicides that offer control are still being worked out
- If you are experiencing something that looks like Waitea patch after preventative applications this spring, then need to sample and identify
- “Yellow Ring” is a basidiomycete fungus and so is generally identified as a fairy ring fungus (fungal hyphae septations have clamp connections)
Samples Going to University of Connecticut, Rutgers University, and Penn State
- CDGA Turfgrass Program is collaborating with colleagues that are currently researching this new disease
- Samples are 1) identified as a basidiomycete and, 2) then shipped for ITS gene sequencing and identification of any fruiting bodies/sporophytes
- Please reach out if you are seeing symptoms of yellow rings on greens
Additional Notes on “Yellow Ring”
- Damage is primarily aesthetic — bright yellow rings indicate Poa annua is under stress
- A superficial fairy ring — fungal activity appears to be limited to the upper most thatch
- Relatively small area impacted — not uniformly distributed across a green’s surface
- Time of year — cool, humid conditions favor cool season turfgrass growth (spring) and this naturally lessens damage caused by hydrophobic conditions associated with fairy ring outbreaks
Moss Research Continues in 2024 by Shehbaz Singh, MS
Moss Control Study 1 (repeat)
In 2024, a repeat study a moss control trial is being conducted at the North Shore Country Club, Glenview. Sponsored by The Andersons Inc., the moss study was initiated on May 6, 2024. In year 2, the study will include the same six 14-day treatments in the same location as the 2023 trial.
Granular products are carefully hand-spread over experimental plots to provide optimum distribution. Quicksilver herbicide, the check, was sprayed in water equivalent to 2 gal per 100 sq ft using a CO2 backpack sprayer at 40 psi with a hand-held three-nozzle boom (XR TEEJET 800VS).
Moss Control Study 2 (new)
A new moss control study was planned as per learnings from 2023. This study is located at a new location in the same creeping bentgrass nursery green at North Shore Country Club, Glenview, IL.
Materials and Methods
The study was conducted using a randomized complete block design with 6 treatments and 4 replications. Individual plot size is 5 ft x 4 ft. The plot size was increased in this study to improve the application consistency and reduce overlapping. Two checks known to control silvery thread moss were included.
Check 1) Baking soda spot treatment (sodium bicarbonate, Church & White). Powdered Arm & Hammer baking soda was mixed with hot water until saturation point. About 28 g of baking soda was mixed in a 16 oz sprayer bottle which was about 1.75 g of baking soda per 1 fl oz of water.
Check 2) 1/2 rate Quicksilver (carfentrazone, FMC Corp.). At 1/2 rate, 8 applications can be utilized for moss suppression per year as per label.
Objectives
- Evaluate moss control
- Evaluate turf quality
- Evaluate turf quality electronically
- Evaluate any phytotoxicity
- Evaluate two rates of Fiesta
- Compare to checks: baking soda spot treatment and 1/2 rate Quicksilver
Measurements
- Visual Quality (1–9 scale, with 6 = minimum acceptable and 9 = best)
- Normalized Difference Vegetation Index (NDVI) using GreenSeeker/Trimble HCS-100
- Moss Infestation (%)
- Phytotoxicity (%)
- Disease (%)
Final Image
