Signs of Spring in Chicago! Soil Temps Over 50, ABW Research, and Bentgrass Variety Trial
The third week of April brought a few early signs of spring, though the spring season is not yet in full swing. Air temperatures have been warmer, and soil temperatures crossed the 50°F threshold — an important milestone for weed, insect and fungal disease activity. In Chicago, early spring is revealing itself through the blooming of various trees, shrubs, and ornamentals. Red maple trees are showing their distinctive reddish blossoms, and weeping willows are beginning to leaf out. Bright yellow forsythia flowers mark one of the first bold signals of the season, joined by the colorful blooms of purple hyacinths. The tiny white flowers of Pachysandra or Japanese spurge have also emerged, along with the vibrant blue of Siberian squill and the cheerful trumpets of daffodils. On the turf side, Kentucky bluegrass is already lush and green across fairways and roughs on golf courses, while creeping bentgrass is just starting to break dormancy. Warmer conditions are ahead, with highs forecasted in the 60s and lows in the 40s next week. Next week will help accelerate turf growth and ornamental development.
Weather Data
Scouting for Insects — Annual Bluegrass Weevil, Listronotus maculicollis
Research sponsored by Syngenta’s WeevilTrak
In the northern Chicago suburbs, two golf course superintendents — Ross Page at Glen Flora Country Club (GFCC) in Waukegan and John Otis at Ravinia Green Country Club (RGCC) in Riverwoods — have been closely monitoring the Annual Bluegrass Weevil (ABW). These courses were the first to report ABW presence in Chicago in 2023, setting the stage for ongoing tracking this year. On March 1, Growing Degree Day (GDD) model tracking was launched on both of these sites using a Spectrum Technologies WatchDog Temp/RH weather station set to a base temperature of 50°F. Additionally, Spiio Sensors were installed at a 3-inch depth in the collar region of a single green at each course to monitor soil temperature and moisture data. As of now, RGCC has accumulated 55 GDDs, while GFCC has recorded 26 GDDs (GFCC in Waukegan is located further north). A Soap-flushing method is used to scout for ABW adult. This technique involves applying a soapy water solution (1 oz of soap per gallon of water) to a 16-square-foot area. However, no ABW adults were found during this initial investigation at either site as of now.
Creeping Bentgrass Varieties for Dollar Spot Resistance & Reduced Inputs — Shehbaz Singh
A creeping bentgrass variety trial has been established at Bob Berry Sunshine Course in Lemont. The site is a USGA specification rootzone that was previously used for two creeping bentgrass variety trials. The first was a 2004–09 National Turfgrass Evaluation Program (NTEP) and the second was a 2009–2012 North Central Region study (NCERA 192) which is a collaboration of a majority of Midwestern turfgrass researchers. The current trial has a total of 20 creeping bentgrass varieties in a randomized complete block design with four replications.
Objectives
- Evaluate establishment rate
- Evaluate dollar spot susceptibility
- Evaluate other desirable characteristics such as spring green up
Materials & Methods
- Each plot (4 ft x 8 ft) was hand-seeded on Aug 28, 2023 at a rate of 1 lb per 1000 sq ft*
- *Landmark Seed Company Match Play and Spectrum bentgrasses were seeded on April 30, 2024
- Slow-release fertilizer was mixed with seed (Forever Green Natural, 4–3–0)
- Grow in of bentgrass saw minimal inputs; 0.15 lbs N per 1000 sq ft as liquid urea in 2023 (Oct 4, Oct 10, and Oct 19).
- Slow-release fertilizer (Forever Green Natural, 4–3–0) 0.5 lbs N per 1000 sq ft per month was applied in 2024 (Apr 16, May 21, Jun 20, Jul 18, Aug 29, and Oct 9).
Data Collection– Every two weeks
- Visual Quality (1–9 scale, with 6 = minimum acceptable and 9 = best)
- Normalized Difference Vegetation Index (NDVI) using GreenSeeker/Trimble HCS-100
- Visual Dollar Spot (% and number of spots per plot)
- Discoloration of Dormant Turf (% per plot) during winter months
- Spring Green-up (1–9 scale, with 6 = minimum acceptable and 9 = best)
Spring Green-Up — Apr 2025
Creeping bentgrass is breaking dormancy as it enters the month of April. No statistical difference exists among varieties for visual spring greenup and normalized difference vegetation index. Only trends were observed. No bentgrass variety has shown an acceptable visual green-up rating of ‘6’ as of now.
Fastest Bentgrass Variety Green-up: Visual rating > 4
- PST-0R20, MatchPlay, and Spectrum
‘Middle of the Pack’ Bentgrass Variety Green-up: Visual rating > 3 and < or = 4
- Barracuda, Piper, PST-0MRN, Puregreen, 777, Centennial, Oakley, PST-0DSF, PST-RODS, Pure eclipse, Macdonald, Flagstick, 007XL, and Piranha
Slowest Bentgrass Variety Green-up: Visual rating < or = 3
- Mackenzie, 007, and Pure Distinction
Dollar Spot Disease Update — Season 2024
In 2024, dollar spot disease development was first observed on July 2 then peak disease development occurred on Oct 9. Statistical differences among bentgrass varieties were only seen on Nov 7 with Centennial, Piper, and Barracuda showing less dollar spot incidence than Flagstick. Over the entire year, creeping bentgrass varieties could be classified by maximum dollar spot levels exhibited.
Dollar Spot less than 10%
- Centennial, Oakley, and Piper
Dollar spot between 10-20%
- 777, Macdonald, Mackenzie, Barracuda, 007, 007XL, PST-MRN, PST-0R20, Pure Distinction, and Puregreen
Dollar spot more than 20%
- Flagstick, Piranha, PST-0DSF, PST-RODS, and Pure Eclipse
Spectrum and Matchplay were not fully established in 2024, hence, not included in the summary. Dollar spot disease data for these varieties will be collected in 2025 along with others.
