Big Rain: Field Day, Cyanobacteria?, Peak Dollar Spot, Seed Germination, White Grubs, and Divot Research

Big rains change a lot of things in a growing season. Just when you were tired of my repetitive use of the word “Dry”. I did that for about a month. It now ends. Plants are wonderful because they are resilient. As an autotroph they are back in the saddle doing what they do best — growing rapidly by making their own food (photosynthesis) given a short list of ingredients that includes water, sunlight and nutrients like N-P-K. Early fall is a special time because it represents ideal conditions for cool-season turfgrass seed germination. Importantly, this is a short period. This optimum window of rapid seed germination and growth usually lasts about 6–8 weeks.

Image 1. A new creeping bentgrass green with a blend of ‘Pure Distinction’ plus ‘Pure Select’ plus ‘Penn A-1’. Settle, Sep 14, 2022

On the landscape, front you should see most of the annual flowers that were planted are still out there doing their thing (in bloom). This week, I was pleasantly surprised by portulaca planted to dress up a city concrete curb. It worked. In September, if you are enjoying the game of golf or are outdoors just remember to look around. Take it in. Watch how quickly our green spaces can recover prior to dormancy (winter). It’s amazing.

Weather Update (Sep 2nd week) by Shehbaz Singh, MS

North Shore CC, Glenview. Temperatures during the week were mostly mild. From Sunday to Wednesday, maximum air temperatures ranged from 66 to 78°F, while on Thursday it reached a high of 82.9. Minimum temperatures are cooling and over the last seven days ranged from 53 to 58°F. The relative humidity over the last seven days ranged from 74 to 97%. Heavy rainfall of 1.3 inches was recorded on Sep 11. The cumulative rainfall over the last seven days was significant. Conditions are wet.

Bob Berry Sunshine Course, Lemont. During the week, maximum air temperatures ranged from 65 to 81°F. Minimum temperatures are cooling and ranged from 50.8 to 57.7°F over the last seven days. The relative humidity ranged from 80 to 87%. Highest relative humidity was experienced on Sunday, September 11. Rainfall in Lemont was significant, but less than some other suburbs — the scattered nature of thunderstorms.

Figure 1. Air temperature and humidity conditions during September, 2022.

2022 CDGA Turfgrass Field Day featuring the USGA Green Section and Wadsworth Golf Charities

September is also an ideal time to review research efforts. It represents a time when we figure out a couple things: 1) what worked, and 2) what didn’t work. We did that this week on Monday, Sep 12 at the Chicago District Golf Association. Technically, it was the 1st ever CDGA Turfgrass Field Day sponsored by the CDGA Turfgrass Green Committee. Attendees were both CDGA Board Members and Golf Course Superintendents and/or their assistants. Zach Nicoludis of the USGA Green Section was in the house to introduce the newest gadgets and gizmos of golf green measurements. Guest speaker Doug Myslinski of Wadsworth also educating us. Did you know the Bob Berry Sunshine Course was renovated by Wadsworth Golf Charites in 2020 with a grow-in occurring the following year?

Image 1. Zach Nicoludis talking about the newer field measurements used to assess golf greens. Settle, Sep 12, 2022

Doug Myslinski told us all about the in’s and out’s of a project that brought us full circle back to 2004 — when the golf course was originally built. The late Carl Hophan always liked to say it was going to be “a living laboratory”. He was right. I’d argue it’s a living laboratory that’s now alive and kicking like never before. New surfaces with current turfgrass varieties and other features PLUS the maintenance help of Cog Hill Golf & Country Club make the difference. Best of all we are able to do extensive research again!

Image 2. Doug Myslinski sharing what was involved during the 2020 renovations of the Bob Berry Sunshine Course in Lemont, IL. Settle, Sep 12, 2022

Big Rain (H2O via Mother Nature)

Big Rain. In this case it was more than we would’ve liked. Some of Chicago’s suburbs saw 4+ inches or even 5+ inches of rain. That’s not such a problem when you are a grower of greens, fairways and tees in September. However if a flash flood event like we just experienced would have occurred about midsummer, I’d be writing about a whole other story. And I have! That story was summers 2010 and 2011. In both those, Chicago’s golf courses flooded on the same date = July 23. Flooding during peak heat is disaster. In those years, Pythium blight became very active and we had to scramble.

Figure 1. A 2022 rainfall event that broke many records in the Chicago suburbs and surround area. Sep 11, 2022

Got Tall Grass? Check out the latest digital edition of the Chicago District’s Golfer magazine

If you ever wanted to know how Chicago District golf courses are progressing in the use of fineleaf fescues in out-of-play areas, well here you go. This golf course trend continues to grow in the United States. Click here to read the article and see a short video.

Image 1. Golf courses have distinct areas of play. In this case 1) a creeping bentgrass fairway, 2) a Kentucky bluegrass rough and 3) fine fescue out of play areas, North Shore Country Club, Glenview, IL. Settle Jul 15, 2022

Blue-Green Algae on Golf Greens (Cyanobacteria)

A type of photosynthetically active gram-negative bacteria with a common name of blue-green algae can occasionally cause problems on greens. But only under very wet conditions. It’s a little confusing on what we call it. Click here to see what Wikipedia says.

It is just another reason that we must rotate our use of fungicides. Some of what we apply in that rotation are generally referred to as contact fungicides or just ‘contacts’. These contacts play an important role in resistance management of fungal diseases like dollar spot. Also, contacts play an important role when conditions are excessively wet because help suppress algal development on sand-based golf green surfaces. Cyanobacteria is a very common issue in the southern United States where ultra dwarf bermudagrass greens annually see tropical weather (and hurricanes). Click here for more on this topic by the USGA Green Section.

Cultural Practices to Suppress Cyanobacteria on Golf Greens

  • Aeration — practices that create holes will help dry overly wet surfaces
  • Adequate fertility — promotes a dense turfgrass canopy
  • Raise mowing height — can reduce incidence of thinning or scalping
  • Sand Topdressing — reduces needed sunlight for Cyanobacteria growth
  • Plant health products — promotes robust plants (phosphites and others)
  • Avoid growth regulation — excessive growth regulation has been associated with algae in southern regions (ultra dwarf bermudagrass)
Image 1. Rapid development of algae (Cyanobacteria) can be a common occurrence on golf greens following large rain events (Sep 11). Newer varieties are not immune. This is green is PC 2.0 creeping bentgrass at Bob Berry Sunshine Course, Lemont, IL. Settle, Sep 15, 2022
Image 2. Closeup of blue-green algae (Cyanobacteria) which initially may look gray to bluish in color. Settle, Sep 15, 2022
Image 3. Micrograph (200x magnification) of rope-like growth of Cyanobacteria. Settle, Aug 24, 2022

Peak Dollar Spot Pressure (Clarireedia jacksonii)

The foliar disease of dollar spot continues to rage. Conditions in Chicago (cool and humid) have been near perfect in September for its development. The host creeping bentgrass is highly susceptible. Herein lies the problem. We continue to gather good data at North Shore Country Club in studies we are conducting at both green and fairway height. Here is an update of select 21 day fairway treatments that were shared 2 weeks ago in August. In total, this study has 17 treatments in a randomized complete block design with 4 replications. Individual, rectangular plot size measures 4 ft by 6 ft.

Image 1. Shehbaz Singh takes an electronic measurement of turfgrass quality which uses the reflectance of far red and near infrared wavelengths (NDVI). North Shore Country Club, Glenview, IL. Settle, Sep 13, 2022
Image 2. Dollar spot progression in untreated is 42.5%. This number represents the mean of 4 replications in an L-93 creeping bentgrass fairway at North Shore Country Club, Glenview, IL. Settle, Sep 13, 2022
Figure 1. Dollar spot disease measurements continue to increase in a L-93 creeping bentgrass fairway study. Note: All treatments are currently seeing some breakthrough. North Shore Country Club, Glenview, IL
Figure 2. Turfgrass quality measurements as influenced by dollar spot in a L-93 creeping bentgrass fairway study. Note: All treatments are currently seeing some breakthrough. North Shore Country Club, Glenview, IL

Annual White Grubs (Complex of Beetle Larvae)

Another sign fall is now happening has to do with an insect pest. It is when a turfgrass manager is out scouting areas and finds they are damaged by being physically ripped apart. This is caused by animals foraging for food such as skunks and raccoon. It turns out, annual white grubs (scarab beetle larvae) are a food source they’ve learned to exploit each fall.

Image 1. Damage in a Kentucky bluegrass golf course rough caused by skunks foraging for annual white grubs. Settle, Sep 14, 2022
Image 2. Damage in a Kentucky bluegrass golf course rough caused by skunks foraging for annual white grubs. Settle, Sep 14, 2022
Image 3. Annual white grub damage signs include being able to easily pull up sod (lack of roots caused by grubs feeding). Beneath you’ll find the scarab beetle larvae/grubs. Settle, Sep 14, 2022

Insecticides are carefully timed in the late spring to early summer and allow us to avoid grub damage. However, applicator skips during application can and do happen. This is one cause of what later can become significant turfgrass injury by annual white grubs.

Expert Information from an Entomologist. Dr. Doug Richmond at Purdue University has assembled a very extensive publication on white grubs in the upper Midwest. Click here to read more on Managing White Grubs in Turfgrass.

Divot Research in Kentucky Bluegrass by Shehbaz Singh, MS

Kentucky Bluegrass divot trial (Spring Initiation). It has been almost five months of evaluating turfgrass divot recovery across multiple divot mix treatments in a Kentucky bluegrass tee at Bob Berry Sunshine Course in Lemont, IL. Most of the treatments are now showing full recovery.

BEST = with seed. The divot mixes which were able to fully recover earliest were: 1) compost + chewings fescue, 2) sand + chewings fescue, and 3) using a sod piece. On Aug 11, or almost after 4 months after divots were made (Apr 19), these three divot mixes showed full recovery. In general, divot mixes with seed showed earlier recovery versus divot mixes without the seed. Chewings fescue seed in divot mixes is useful and was suggested by Zach Nicoludis of the USGA Green Section.

MIDDLE OF THE PACK = without seed. The 8–1–1 mix (80% sand, 10% compost, and 10% soil) and the compost-only treatments showed full recovery later on Aug 24.

WORST = doing nothing or sand-only. The untreated treatment showed full recovery on Sep 7 and was similar to the sand-only treatment. In fact, the sand-only treatment showed just 80% recovery by Sep 7.

PUZZLING = possible seasonal effect. Interestingly, the 8–1–1 mix + chewings fescue treatment (pink line) showed only 80% recovery by Sep 7. This divot mix was the first to show 80% recovery on Jun 9 versus other treatments but somehow its recovery would plateau and then remain at the same level. This suggests the recovery potential of the 8–1–1 mix + chewings fescue may have been negatively impacted by environmental conditions in summer.

Figure 1. Spring Divots: Visual estimate of HGT Kentucky bluegrass divot recovery (%) for different divot mixes at Bob Berry Sunshine Course in Lemont, IL.

Kentucky bluegrass Divot trial (Summer Initiation). For the summer divot trial, similar findings are occurring. Again, the recovery potential of the 8–1–1 mix + chewings fescue treatment (pink line) may have been negatively impacted by environmental conditions in summer.

Figure 2. Summer Divots: Visual estimate of HGT Kentucky bluegrass divot recovery (%) for different divot mixes at Bob Berry Sunshine Course in Lemont, IL.

Final Photo

Portulaca grandiflora found helping out a telephone pole and curb in Chicago suburbia. Settle, Sep 16, 2022

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CDGATurfgrassProgram

Dedicated researchers and turf pathologists working for golf course superintendents in the Chicago area.