Summertime! 1st Heat Wave, Dollar Spot begins, Take-all Patch again?!? and Native Flowers
Summertime And the livin’ is easy Fish are jumpin'… as the 1930s play goes. It certainly isn’t easy in summer if you are a grower. We are now off to the races with cool season turfgrass. On one hand, all or our important turfgrass species are now growing in sync — good news for those (golf course supes) that manage a mixture of Poa annua and creeping bentgrass as golf greens and other surfaces. On the other hand, we now quickly shift into summer mode given, 1) Rapid development of certain diseases are possible (frequent scouting required), 2) Daily monitoring of plant health is critical (roots), and 3) Backing off stressful practices with agility to meet the needs of cool season turfgrass physiology (extended periods of excessive heat is a primary contributor of summer bentgrass decline).
In the landscape, the very large (and native) northern catalpa or C. speciosa are now in a fantastic full white bloom — a rather exotic flower for a tree. Also don’t forget to check out the diversity of roses (hybrid tea, floribunda, grandiflora, climbing, etc.) in bloom throughout the month June. What’s next for turf enthusiasts? Forecasted weekend highs this Sat-Tue in Chicago are 95, 97, 96, 95. If high humidity also occurs, it means our first triple digit heat indices will be experienced. During summer’s first heat wave (this weekend) superintendents will carefully monitoring everything. Plant health will be tracked much more closely AND scouting for disease will occur with greater frequency. Summer’s pop-up thunderstorms create conditions for rapid development of our most common foliar diseases (dollar spot, brown patch and Pythium blight). And if it gets dry, wilt watch of sand-based greens takes center stage. When outdoors this week, be proactive. Drink plenty of fluids and know how to stay safe on the golf course.
Scouting for Disease — Dollar Spot (Clarireedia jacksonii)
Our first major fungal disease outbreak arrived this week. Dollar spot, is the nemsis of a majority of turfgrasses used for recreational purposes. Creeping bentgrass and Poa annua are both highly susceptible to this foliar disease. One reason that a backyard putting green is a really bad idea can be blamed on dollar spot.
Dollar spot infection creates bleached white lesions on leafs that sometimes look like an hourglass. Infection centers then result and the height of cut determines their size — about the size of a dime on creeping bentgrass greens and the size of a silver dollar in roughs. Advances in turfgrass breeding efforts mean newer varieties of creeping bentgrass now have good resistance to dollar spot disease. No doubt this will lead to a reduction in the amount of fungicides used on golf courses.
Dollar Spot Resistant Creeping Bentgrass
All that is required is the right variety. See the NTEP (National Turfgrass Evaluation Program) testing information for your area. For example, Illinois would by wise to use West Lafayette, Indiana or Purdue University. Best varietes for a creeping bentgrass fairway (1–9 rating scale) turned out to be Spectrum (8.5), Piper (8.2), 007XL (8.0), and Oakley (7.8). Note: You want a high number, 9.0 = no dollar spot.
2023 DATA
Chemical Control
See page 15–16 in Chemical Control of Turfgrass Diseases 2024.
Scouting for Disease — Take-all Patch (Gaeumannomyces graminis var avenae)
It happens every June just as temperatures warm and first midday wilt stress is experienced. Yes, we are now seeing take-all patch in fairways with a history of the disease. If you noticed the latin name is a mouthful and to spell it correctly you probably should just cut and paste it. But I digress.
If you remember last year we saw record wet conditions during spring and therefore saw a greater number of take-all patch cases in creeping bentgrass fairways. It’s still early, but the take-all patch we are experiencing in 2025 has been lessened by the dry conditions that were experienced this spring. Stay tuned.
Cultural Practices & Fungicide Recommendations for Take-All Patch (TAP)
- Factors that restrict root growth are known to increase TAP severity (compaction of clay soils by concentrated cart traffic problematic)
- Applications of light, frequent fertilizer are helpful (post-infection)
- Wetting agents may provide faster recovery (see CDGA research below)
2024 CDGA Take-all Patch Research
In summer 2024, a take-all patch (TAP) study was conducted in a creeping bentgrass fairway at Prairie Bluff Golf Course in Lockport, Illinois. In a curative application situation, we found a wetting agent was a good recommendation. The wetting agent used was Excalibur by AQUA-AID Solutions.
TAP Study Background and Results
Initial signs of disease were reported on June 3 and curative applications were made 21 days apart on June 17 and July 8. The data suggested a wetting agent alone is a good strategy versus post-infection fungicide use.
- Disease control was significantly different from untreated in all treatments using area under the disease progress curve (AUDPC), but no treatment completely controlled the disease during the study period (Figure 1).
- First acceptable visual quality (6.0 or greater) occurred in Excalibur treatments on August 7 (Figure 2).
Wetting Agent Use for Curative Applications
Fairway TAP situations are somewhat common and so it is a difficult to control disease that can impact large acres. Because preventative fungicide applications do not always work in creeping bentgrass fairways, a curative solution is needed. Wetting agents likely work by lessening symptoms and thus aid creeping bentgrass recovery.
Chemical Control
Take-all patch fungicides should be used preventatively. Timings are in the spring and based on soil temperature data. See page 26 in Chemical Control of Turfgrass Diseases 2024.
Illinois Native Plant Demo at Bob Berry Sunshine Course in Lemont, IL
We continue to track the native flowers established in 2024 at Bob Berry Sunshine Course in Lemont, IL. We are collecting data to better understand the design, maintenance and associated pollinators. This represents a native flower demo placed in an out-of-play landscape area on a golf course.
Spring 2025 Observations
- Early May — During the month of May few flowers were growing or in bloom. One, Golden Alexander, fills in this flowerless gap nicely because it grows and flowers during cool conditions.
- Late May — Spiderwort began to flower in late May.
- Early to Mid-June — By late May to early June Sand Coreopsis began to bloom and by mid-June was already reaching mid- to peak bloom.
- Late June (this week) — Swamp Milkweed and Prairie Clover began to bloom.
Education & Communication by CDGA’s Green Committee
“Over the years, golf courses have taken the role of environment conservation very seriously, and they continue to play an important part in supporting local ecosystems.”
Final Photo
“The oldest remains of roses are from the Late Eocene Florissant Formation of Colorado. Roses were present in Europe by the early Oligocene.
Today’s garden roses come from 18th-century China. Among the old Chinese garden roses, the Old Blush group is the most primitive, while newer groups are the most diverse.” see Wikipedia
