Dry! Hot Forecast, Brown Patch, Bentgrass Variety Trial, Broadleaf Weed Research

A dry, period with cool nights. Sounds pretty good right? And we’ve just experienced. It was a needed reprieve from August’s third week —that late summer heatwave which gave us record heat index material. And it was a little scary if honest. Thankfully, it represented a rare combination for us — maximum heat plus maximum humidity levels. Also known as, When Chicago feels like Atlanta! But as quickly as it began, it ended. The technical term? A break. Low humidity with cool nights returned. However, a new round of heat is set to begin as September starts. To be sure that forecast is raising some ‘turfgrass eyebrows’ — looks like a repeat. “Another four days with 90 degree highs?” However, this is to be a dry heat.

Image 1. The silvery sheen of turfgrass? The edge of a Penn A1/Penn A4 practice green is caused by dry conditions which not surprisingly has progressed during a week without rain. During hot periods, watering by hand is a critical practice used in sand-based root zone systems. Bob Berry Sunshine Course, Lemont, IL. Settle, Aug 31, 2023

High ET (evapotranspiration) rates are now as September begins. Water inputs will be adjusted (up) as required whether you are a golf course fairway or a lawn in the landscape. And a new change has begun to drive the squirrels (Sciurus) nuts. That’s right, acorns have begun falling from oak (Quercus) trees. Soon they’ll appear in abundance on streets, on sidewalks, on turfgrass. And about now (September) each growing season seems to take a pause. And up next, deciduous trees will begin their fall color. In the meantime, we are to be warmer and drier than usual. Growing season 2023 is making a WARM turn for the finish line. Enjoy Labor Day!

Weather

Figure 1. Story of the week was all about night temperatures falling into the 50s. In fact, our first sub-50 degree night occured (47 degrees) at August’s end, Bob Berry Sunshine Course, Lemont, IL.

Figure 2. The month of September is to expect above normal temperatures for a majority of the United States. Courtesy NOAA

Figure 3. The month of September is to expect below normal precipitation for a majority of the Midwest. Courtesy NOAA

Brown Patch (Rhizoctonia solani) had a good run in 2023 = July and August

We saw more brown patch this growing season than one might have expected. It was all about night temperatures (warm — near 70 degrees) and humidity (high — creating a leaf wetness duration of 10 hours or more). Indeed, it is a start and stop development, but that’s how nature works.

Cool Conditions Will End Brown Patch Development

Once lows begin to fall into the 50s (September) this disease is no longer able to develop. The next time we will see this disease will be summer 2024.

Susceptible Turfgrass Species Also Required

Look for newer varieties that have been selected for genetic resistance to brown patch. This is especially important for tall fescue (highly susceptible).

• Tall fescue (Festuca arundinacea)
• Perennial Ryegrass (Lolium perenne)
• Creeping bentgrass (Agrostis stolonifera)
• Annual bluegrass (Poa annua)

Good Resistance to Brown Patch

Kentucky bluegrass has very good, natural resistance to brown patch. This sets it apart from the majority of other cool season turfgrasses we use.

• Kentucky bluegrass (Poa pratensis)

Image 1. Perennial ryegrass, like tall fescue, is highly susceptible to brown patch (foreground). Bob Berry Sunshine Course, Lemont, IL. Settle, Aug 26, 2023

Image 2. Close up of brown patch developing in a perennial ryegrass/Poa annua tee, Bob Berry Sunshine Course, Lemont, IL. Settle, Aug 26, 2023

Image 3. Dollar spot was developing in the same perennial ryegrass/Poa annua tee as was the brown patch, but it does not have the same patch appearance, Bob Berry Sunshine Course, Lemont, IL. Settle, Aug 26, 2023

Image 4. Leaf lesions are useful when distinguishing foliar diseases of turfgrass in the field. When conditions are hot and humid, dollar spot and brown patch can be active at the same time. In this case, the bleached-white lesions tell us that this infection of Poa annua is dollar spot (Clarireedia jacksonii) and not brown patch (Rhizoctonia solani). Settle Aug 26, 2023

New Creeping Bentgrass Variety Trial — August 31, 2023 by Shehbaz Singh, MS

Introduction

Creeping bentgrass (Agrostis stolonifera) is the most widely used cool season turfgrass for golf greens. Cultivars Penn A-1 and Penn A-4 alone or in combination have been commonly used in the Chicagoland area since about 2000. However, both are susceptible to dollar spot (Clarireedia jacksonii). Intensive breeding efforts has led to newer creeping bentgrass cultivars with improved characteristics. Dollar spot resistance is one.

Materials and Methods

A new trial was seeded on August 31, 2023 to evaluate the performance of newer creeping bentgrass cultivars at green height. This variety trial is being conducted on a nursery green at the Bob Berry Sunshine Course in Lemont. The experimental area has a USGA specification rootzone. Previously this area was used for a North Central Region (NCERA221) creeping bentgrass study (2008–2012).

Objectives

1. Evaluate the establishment rate of each cultivar at green height.
2. Evaluate the dollar spot susceptibility of each cultivar at green height.
3. Evaluate the agronomic parameters and quality of each cultivar at green height.

Image 1. Shehbaz Singh carefully seeds a plot of a creeping bentgrass variety trial in a sand-based nursery green. Bob Berry Sunshine Course, Lemont, IL. Settle, Aug 31, 2023

Image 2. The creeping bentgrass variety trial is located nearest green number 3 on Bob Berry Sunshine Course, Lemont, IL. Settle, Aug 31, 2023

Table 1. Entry, variety and seed source of a creeping bentgrass variety trial at green height, Bob Berry Sunshine Course, Lemont, IL.

Table 2. Map of 4 ft by 6 ft plots in a creeping bentgrass variety trial arranged in a randomized block design with 4 replicates, Bob Berry Sunshine Course, Lemont, IL.

Broadleaf Weed Research — August 31, 2023 by Shehbaz Singh, MS

As part of our company-sponsored turfgrass research in 2023, a PBI Gordon study is being conducted to evaluate broadleaf weed control with herbicides in a no-mow fine fescue area.

Objectives

1. To evaluate post broadleaf weed control in no-mow fine fescue.
2. To evaluate any turfgrass injury or phytotoxicity.

Materials and Methods

The study is being conducted on newer fine fescue mounds at Bob Bery Sunshine Course in Lemont. Fine fescue mounds were mild to severely infested with a primary broadleaf weed called wild lettuce (Lactuca virosa). Plot size was 5 ft by 5 ft (25 sq ft) and used a total of 6 replicates in a randomized complete block design. Applications were made using a CO2 backpack sprayer operated at 40 psi that used a three nozzle boom (XR TEEJET 8004VS). Treatments applied in water equivalent to 2 gal per 1000 sq ft.

Treatments

1. Untreated
2. Herbicide 1 (2 apps-one month apart @ 4pint/acre )
3. Herbicide 2 (2 apps-one month apart @ 4 & 8 pint/acre)
4. Herbicide 3 (2 apps-two month apart @ 4 pint/acre)
5. Herbicide 4 (2 apps-one month apart @ 4 pint/acre)
6. Herbicide 5 (2 apps-one month apart @ 4 pint/acre)
7. Herbicide 6 (3 apps-one month apart @ 4 pint/acre)

Data Collection–each week

• Visual Quality using 1–9 scale, with 6 = minimum acceptable and 9 = best
• Normalized Difference Vegetation Index (NDVI) using GreenSeeker/Trimble HCS-100
• Weed Infestation (% per plot)
• Weed Height (average per plot)
• Healthy Weeds (number per plot)
• Unhealthy Weeds (number per plot)

Table 1. PBI Gordon Herbicide Programs that used either two or three applications. Note: Program 3 used a split application (timing A and C) and only Program 6 used three applications (timing A, B, C).

Figure 1. Percent broadleaf weeds of postemergent herbicide treatments in a no-mow fine fescue study. Programs 1, 2, 4, and 5 consisted of two applications (Jun 20, Jul 17), Bob Berry Sunshine Course, Lemont, 2023.

Figure 2. Control of broadleaf weeds of postemergent herbicide treatments in a no-mow fine fescue study. Programs 1, 2, 4, and 5 consisted of two applications (Jun 20, Jul 17), Bob Berry Sunshine Course, Lemont, 2023.

Figure 3. Percent broadleaf weeds for postemergent herbicide treatments in a no-mow fine fescue study. Program 3 consisted of two split applications made at beginning and end of the treatment period (Jun 20, Aug 21), Bob Berry Sunshine Course, Lemont, IL, 2023.

Figure 4. Control of broadleaf weeds for postemergent herbicide treatments in a no-mow fine fescue study. Program 3 consisted of two split applications made at beginning and end of the treatment period (Jun 20, Aug 21), Bob Berry Sunshine Course, Lemont, IL, 2023.

Figure 5. Percent broadleaf weeds for postemergent herbicide treatments in a no-mow fine fescue study. Program 6 consisted of three applications (Jun 20, Jul 17, Aug 21), Bob Berry Sunshine Course, Lemont, IL, 2023.

Figure 6. Control of broadleaf weeds for postemergent herbicide treatments in a no-mow fine fescue study. Program 6 consisted of three applications (Jun 20, Jul 17, Aug 21), Bob Berry Sunshine Course, Lemont, IL, 2023.

Final Photo

‘Sweet Autumn’ Clematis (C. ternifolia) is a flower we enjoy in the landscape each fall. Settle Aug 31, 2023. See more from Wikipedia. Clematis is a genus of about 380 species. Their garden hybrids and cultivars have been popular among gardeners, beginning with Clematis ‘Jackmanii’, a garden staple since 1862; more cultivars are being produced constantly. They are mainly of Chinese and Japanese origin.