Wet! Saturated Soils, New Yellow Ring Disease, Broadleaf Weeds, and Moss Research

CDGATurfgrassProgram
6 min readMay 10, 2024

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.

Image 1. Native oak trees fully leafed out (or nearly so) is a true sign of spring in Chicago’s suburbs, Arrowhead Golf Club, Wheaton, IL. Settle, May 9, 2024

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

Figure 1. Air Temperature highs are influenced by thunderstorm activity. Cool days (60s for highs) typically associated with cloud cover and rainfall events. Bob Berry Sunshine Course, Lemont, IL
Figure 2. Frequent rainfall is beginning to become a factor in spring 2024. Currently, native soils are saturated and overly wet, Bob Berry Sunshine Course, Lemont, IL
Figure 3. Much of the United States received precipitation during May’s first week. Courtesy NOAA

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.

Image 1. Scouting for thistle in an out of play area planted to fescue, but also allows for Illinois native flowers such as swamp milkweed and common milkweed. Settle, May 8, 2024
Image 2. Spot treatment of a herbicide to selectively control broadleaf weeds like thistle is both effective and necessary. This preserves desirable native flowers like milkweeds because broadcast applications are not used. Settle, May 8, 2024
Image 3. Native swamp milkweed emerging is protected by careful application of any herbicide. Settle, May 8, 2024

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.

Image 1. A single patch (foreground) of a new “yellow ring” disease on a creeping bentgrass/Poa annua green. Surrounding turf is without ring symptoms. Settle, May 8, 2024
Image 2. Two dinner plate size patches of a new “yellow ring” disease on a creeping bentgrass/Poa annua green collar. Settle, May 8, 2024
Image 3. Patches of “Yellow Ring” appear very circular and sometimes with a somewhat darker green interior. Patch size ranges from a 2 inches (pictured) to that of a dinner plate (12 inches or more). Settle, May 8, 2024

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).

Table 1. Treatments for a repeat 2024 moss control study conducted in a ‘SR119’ plus ‘Providence’ creeping bentgrass nursery green, North Shore Country Club, Glenview, IL.
Image 1. 2024 Repeat moss control study. Located in the lowest area of a ‘SR119’ plus ‘Providence’ creeping bentgrass nursery green, North Shore Country Club, Glenview, IL. Settle, Jun 10, 2023
Figure 1. Residual Moss Infestation (May 6, 2024). A total of 8 applications were made every 14 days on a ‘SR119’ plus ‘Providence’ creeping bentgrass nursery green from Jun 10 to Oct 13 in 2023. The first application for the 2024 trial was made on May 6, 2024. North Shore Country Club, Glenview, IL
Image 2. Photos of select treatments of a 2 year moss control study [A] Untreated, [B] Quicksilver, [C] Castaway, and [D] Fiesta at North Shore Country Club, Glenview, IL. Singh, May 8, 2024
Figure 2. Residual Visual Turf Quality (May 6, 2024) of treatments to control moss in a creeping bentgrass nursery green. A total of 8 applications were made every 14 days from Jun 10 to Oct 13 in 2023. The first application for the 2024 repeated trial was made on May 6, 2024. North Shore Country Club, Glenview, IL

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.

Image 3. Nursery green is ‘SR1119’ plus ‘Providence’ and Poa annua (two species estimated at 80–90% bent and 10–20% Poa). The study is being conducted at a new location where moss infestation was most prevalent, North Shore Country Club, Glenview, IL. Singh, May 8, 202

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.

Table 2. Treatments for a new 2024 moss control study conducted in a ‘SR119’ plus ‘Providence’ creeping bentgrass nursery green, North Shore Country Club, Glenview, IL.

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 (%)
Figure 3. Initial Moss Infestation (May 6, 2024) on a creeping bentgrass nursery green. The first application was made on May 6, 2024. Fisher’s LSD (p<0.05). North Shore Country Club, Glenview, IL
Image 4. Moss Infestation in block 1, at study start (May 6, 2024). on a creeping bentgrass nursery green. The first application was made on May 6, 2024. North Shore Country Club, Glenview, IL
Image 5. Moss Infestation in block, 1 two days after study start (May 8, 2024). on a creeping bentgrass nursery green. The first application was made on May 6, 2024. North Shore Country Club, Glenview, IL

Final Image

Allium is a bold flower, but hard not to appreciate and grows well in the Great Lakes region. Settle, May 8, 2024 “Plants of the genus Allium produce chemical compounds, mostly derived from cysteine sulfoxides, that give them a characteristic onion or garlic taste and odor. Many are used as food plants, though not all members of the genus are equally flavorful. In most cases, both bulb and leaves are edible. The characteristic Allium flavor depends on the sulfate content of the soil the plant grows in. In the rare occurrence of sulfur-free growth conditions, all Allium species completely lose their usual pungency.” For more see Allium on Wikipedia here.

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CDGATurfgrassProgram

Written by Derek Settle, PhD & Shehbaz Singh, MS. Mission: Provide science-based turfgrass research and diagnostics to 400+ member golf courses/superintendents.