Cool & Wet! Sand Bunker Education, Melting Out, Yellow Tuft, Fairway Research
It is now clipping along. Fall season that is. Cool nights are a regular thing. Days are both shorter and darker (long periods of light rain and cloud cover double-down with regularity). This ‘environmental information’ begins a shift toward winter dormancy of plants (insert cool season turfgrass here). The details are both interesting and… well complicated. Best explained by a plant physiologist in a book called Plant-Environment Interactions. As C.B. Rajashekar explains, “Although most temperature plants have low tolerance to freezing during their active growth in summer, they typically acquire an ability to tolerate freezing during the fall in response to environmental cues.” Low temperature and short photoperiod (short days) are most responsible for beginning the changes we know as cold acclimation. It all happens at a plant’s cellular level: 1) Dehydration occurs to remove freezable water, 2) Accumulation of sugars and other osmolytes, 3) Plant cell membranes change their structure and lipid composition, and 4) Modulation of gene expression. In sum, cold acclimation is a necessary but complicated transformation to avoid winter kill. In Sep, it is happening!
In the landscape things are nuts. Acorns of oak trees (Quercus) have either fallen or are now falling just about everywhere. I even found myself, ouch, dodging several large (and impressive) falling horse chestnuts (Aesculus). Aerification of golf greens, tees and fairways is still occuring on schedule (a 60 day window from Aug to Sep). And the first large turfgrass education event this fall was well attended. The Illinois Landscape Contractors Associations' meeting is simply called TED (turf education day). It was a success! Up next? Consider attending the upcoming CDGA Turfgrass Seminar on Saturday, Oct 14. Until then, enjoy this fall season and see if you can say COLD ACCLIMATION five times in a row — quickly. Good luck!
Fall Turfgrass Education — SAVE THE DATE
1. CDGA Turfgrass Seminar Saturday, October 14
Round Table Discussion on Sand Bunker Technology at CDGA’s Midwest Golf House and a Field Trip to Cog Hill Golf & Country Club in Lemont.
- Superintendent Panel: Reed Anderson and Don Cross
- Industry Expert: Doug Myslinski
- See Chicago’s Newest Bunkers: Cog Hill’s Dubsdred Course
Melting Out, Drechslera Diseases (Pyrenophora)
Three Quick Facts
1) A leaf spot fungal disease that occurs during cool, humid, overcast periods.
2) Older Kentucky bluegrass roughs and lawns can be very susceptible.
3) Previously known as Helminthosporium leaf spot.
- Promote moderate growth with nitrogen.
- Do not overstimulate growth early spring/summer.
- Water infrequently, deeply (not afternoon/evening).
- Genetic resistance, use newer cultivars Kentucky bluegrass, perennial ryegrass, creeping red fescue.
- Where severe = Fungicides are labeled (avoid DMI class for this disease)
Yellow Tuft (Downy Mildew)
Not too surprisingly more and more yellow tuft has been found during scouting this week. The increasingly cool, wet conditions this fall season have been promoting this disease which was first reported on a Penn G2 creeping bentgrass green the first week of September (Tim Christians, GCS, Makray Memorial Golf Club).
Three Quick Facts
- It is very likely that just about every golf course in Chicago currently has this problem.
- The combination of conducive environmental conditions (cool, wet) and a susceptible host (creeping bentgrass) is all that is needed.
- All surfaces can be negatively impacted — greens, tees, fairways.
- New creeping bentgrass varieties are susceptible (observations below)
- Green height — Penn G2 (superintendent), Pure Distinction (superintendent), OO7 (Sunshine Course)
- Tee height — PC 2.0 (Sunshine Course)
- Fairway height — OO7 (Sunshine Course)
- Cultural — Use vertical cutting to dethatch yellow-tufted plants on greens.
- Preventive fungicides— Mefenoxam (Subdue Maxx) is the most effective chemistry when applied preventatively.
- Curative fungicides— Fungicides provide little to no curative control.
Compendium of Turfgrass Diseases (fourth edition). 2023. Tredway, Tomaso-Peterson, Kerns, and Clarke, editors
Fairway Research — September 21, 2023 by Shehbaz Singh, MS
As a part of monthly evaluation of greens, fairways, and tees at Bob Berry Sunshine Course, all fairways were evaluated this week.
Investigations evaluate playability, agronomic characteristics, and quality. There are total of four creeping bentgrass fairways with different varieties.* *Fairways were renovated in 2020 by Wadsworth Golf Construction Co.
- Fairway 1: Crystal Bluelinks, 17,377 sq ft
- Fairway 2: OO7, 10,254 sq ft
- Fairway 3: Pure Select, 8,089 sq ft
- Apron: Pure Eclipse, 2,000 sq ft
On each fairway, three points were selected in a systematic way using a straight center line in front (approach), middle, and back. Four data readings or samples were collected around each of the three marked points. Six sets of data were collected (see below).
- Visual Quality (1–9 scale with 9 best and 6 = minimum acceptable)
- Normalized Difference Vegetation Index (NDVI) was measured using GreenSeeker by Trimble.
- Soil Moisture was measured using TDR350 by Spectrum Technologies, Illinois.
- Surface Firmness was measured using Field Scout TruFirm by Spectrum Technologies, Illinois.
- Shear Strength was measured using Shear Tester by Turf-Tech International, Florida.
- Weeds (%) was visually estimated around each point in about area of a 5 ft radius circle.
- Localized Dry Spot (%) was visually estimated around each point in about area of 5 feet radius circle.
- Root Length (in) was measured taking the average of four 0.5-inch diameter soil core samples (maximum root length)
- Organic Matter Accumulation(in) was measured taking the average of four 0.5-inch diameter soil cores.
- Root-Feeding Nematodes were extracted by lite sucrose centrifugation using 100g soil (upper 2-inches of four soil cores). Four samples or data readings were collected around the point for each parameter.