Fall! Rain Returns, Dollar Spot Pounces, Fairway Fairy Ring, White Grubs, and Newest Moss Research
Fall “officially arrived” on Sunday, September 22 at 7:44 am in Chicago. The official timing varies year to year and has to do with the occurrence of the autumnal equinox — when the sun is directly above the earth’s equator. Only then are day and night periods roughly equal (12 hours each). From here on out, our days will shorten and our nights will lengthen. A wise superintendent (Dave Ward) taught me long ago that we lose something like 2–3 minutes each day until winter solstice. That’s in December and is experienced when the earth’s axis is tilted farthest away from the sun. In a week, cool temperatures pushed out our final heat wave of 2024 (fingers crossed). And what came next was what some growers had been dancing and praying for all of September. It actually rained!!!
In 2024, fall recovery from summer stress had to wait for many due to especially dry conditions. Bare areas without irrigation will need re-establishment or the risk of soil erosion will exist. One month (October) remains of what is considered the ideal period of cool season turf establishment by seed. Unlike spring, right now (fall) is when soil moisture levels are less volatile and weed competition is low. Golf course superintendents are finishing out this growing season in very good shape though a dramatic resurgence of dollar spot provided a social media post or two?!? No doubt golfers are grateful to have experienced some of the best playing conditions all year in September (when dry is a good thing). Growing season 2024 is in the books. This one should’ve made you smile whether you’re a gardener, a landscaper, a golf course superintendent, a golfer, or even… a turfgrass scientist. This will be the final Turfgrass Scouting Report of 2024. We will now turn our attention to building an educational video series, as well as writing oodles of research reports. We’ll see you next year!
The CDGA Turfgrass Program Acknowledges Generous Support in 2024
2024 Wadsworth Endowment Contributors & Turf Research Funding
- Corteva — This is your turf. Let’s help you make the most of it. https://www.corteva.us/products-and-solutions/turf-and-ornamental.html
- NuFarm — As a leader in turf and ornamental plant protection, we balance innovation and improvement in efficiency, safety and simplicity to bring you a focused product portfolio that saves time, delivers results and safeguards your success. https://nufarm.com/usturf/
- Syngenta — Our commitment to the industry goes far deeper than the products we manufacture. We take great pride in empowering turf professionals and their respective industries. https://www.greencastonline.com/golf
2024 CDGA Turf Research Funding
- The Andersons — We provide next-generation fertilizers, soil amendments, and control products to the golf, sports turf, lawn and landscape, and horticulture markets throughout the U.S. and around the world. https://www.andersonsinc.com/products-services/#turf
- Aquatrols — The world leader in the development of cutting-edge soil surfactants and wetting agents that maximize the water and soil relationship. https://aquatrols.com/
- BASF — BASF Turf delivers innovative solutions for golf, lawn, sod, and sports turf managers who seek healthy, improved turf quality. https://pss.basf.us/turf-ornamentals.html
- Envu — A new vision for a company built not from the ground up but on top of 50 years of environmental science experience. https://www.us.envu.com/
- Harrell’s — Growing a Better World. https://www.harrells.com/
- PBI Gordon — Providing a robust line of herbicides, insecticides and other products in the turf & ornamental management industry. https://www.pbigordonturf.com/
- RhizoSolutions LLC — Founded with the simple vision of bringing new innovative technologies — based on real science — to global turf and agricultural markets. https://rhizosolutions.com/
2024 Fairways Foundation Grant
- The FairWays Foundation — Not Changing the Whole World … Just Your World. https://thefairwaysfoundation.com/
“Environmental stewardship is not an initiative. It is a long-term investment into our future and the future of our industry. The FairWays Foundation directly funds local and global projects that advance the conservation of our natural resources. These projects help to preserve the environment we live and work in whilst encouraging education and stewardship not only within our own industry but also within wider communities.”
Weather
Scouting for Disease s— Dollar Spot vs Creeping Bentgrass (Clarireedia jacksonii)
The most common (and frustrating) foliar disease of many turfgrass species we use is dollar spot. Plant breeders have begun to change that especially when it comes to creeping bentgrass (Agrostis stolonifera). Newer varieties of creeping bentgrass have good levels of dollar spot resistance. For large acre areas in play such as fairways and tees, reduced fungicide use is now possible while still maintaining acceptable turf quality.
However, preventative fungicide applications to suppress dollar spot will remain necessary. Newer systemic fungicides may offer more flexibility by having greater residual control of dollar spot. A L-93 creeping bentgrass fairway fungicide study nicely illustrated this in 2024.
Scouting for Disease s— Fairy Ring vs Creeping Bentgrass Fairways (multiple basidiomycete fungi)
We continue to see evidence of type 1 fairy ring that negatively impacted golf course fairways from mid- to late summer in 2024. It suggests that current preventative timings of broad spectrum fungicides (DMIs) in the spring are not providing adequate control of fairy ring during peak summer heat in fairway situations.
- Diagnosis is difficult because signs of mycelium in the field can be hard to find —usually in the upper thatch layer.
- No fruiting structures present — in many cases fairy ring mushrooms or puff balls are absent.
- An additional summer timing (early July) is suggested for fairways with a history of type 1 fairy ring.
Scouting for Insects — Annual White Grubs (numerous beetles contribute these larvae)
A primary issue of all turfgrass areas in the fall is damage caused by root-feeding white grubs. Often areas impacted are small, but the resultant damage can be significant enough that reestablishment is required.
Usually multiple factors are involved
- High grub populations
- Drought stressed turf (September in Chicago)
- Animals and/or birds digging up turf
Animal Damage and Grubs — from University of Illinois Fact Sheet
- Raccoons will roll back large areas of turf a foot or more wide
- Skunks will typically dig up small, 2- to 3-inch diameter divots of sod to eat the grubs underneath. A single skunk may make 100 of these small holes per night.
- Insect-eating birds, such as starlings, will peck through the turf to obtain and eat the grubs.
All of these animals will damage turf that appears to have as few as 3 to 5 white grubs per square foot, thus causing injury in areas where grub numbers are below as well as above turf-damaging levels. White Grub Fact Sheet
Newer Methods to Control Silvery Thread Moss in Creeping Bentgrass Greens — excerpts from a scientific poster presentation by Shehbaz Singh, MS
Fast Ball Roll Speeds and Moss
Silvery thread moss is a cosmopolitan weed of sand-based creeping bentgrass putting greens. Once introduced, moss is problematic given a majority of putting green cultural practices are conducted not to benefit plant health, but to ensure fast ball roll speeds.
Mower Scalping and Moss
Moss is worst in surface design features (ridges and knolls) and outer perimeter clean-up laps because scalping by mowers can exist due to low mowing heights. Once moss is established, creeping bentgrass is unable to compete given reduced nitrogen fertility and plant growth regulator use are necessary cultural practices for putting greens.
Alternative Control Solutions Needed
Alternative ways to suppress moss are needed given repeat applications of a single postemergent herbicide (carfentrazone) is currently used for the suppression of slivery thread moss.
2024 Moss Study Treatments (6 total)
- Eight applications on 14-day intervals in 2024 (May 6, Jun 3, Jun 17, Jul 1, Jul 15, Jul 29, 12-Aug, and 26 Aug).
- Granular treatments were hand-applied to ensure uniform distribution across each plot — watered in.
- Quicksilver herbicide was applied using a CO2-powered backpack sprayer operated at 40 psi with XR TEEJET 8004VS nozzles using 2 gallons water carrier/1000 sq ft — not watered in.
- Sodium bicarbonate (dissolved baking soda) was spot-applied using a sprayer bottle at 0.04 oz per 16 oz water — not watered in
2024 Moss Study Results
2024 Moss Study Discussion
As expected, Quicksilver (carfentrazone) provided silvery thread moss control in a creeping bentgrass putting green. However, we found two fertilizer products, Fiesta and Castaway DG, are promising alternatives for moss control. Rate of Fiesta is critical because too much nitrogen will risk excessive growth and scalp injury by mowers.
2024 Moss Study Conclusions
- A spot treatment, sodium bicarbonate, was found to be phytotoxic and is not recommended.
- Castaway DG is interesting because it contains a low nitrogen tea extract (saponins) that can provide moss control with repeat applications.
- Unlike Fiesta, Castaway DG never resulted in mower scalping.
- A programmatic approach integrating QuickSilver with alternatives is now possible.
Final Image
“The eastern North American monarch population is notable for its annual southward late-summer/autumn instinctive migration from the northern and central United States and southern Canada to Florida and Mexico. During the fall migration, monarchs cover thousands of miles, with a corresponding multigenerational return north in spring. The western North American population of monarchs west of the Rocky Mountains often migrates to sites in southern California, but individuals have been found in overwintering Mexican sites, as well. Non-migratory populations are found further south in the Americas.” For more see Monarch butterfly — Wikipedia
