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.
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!
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)
New Creeping Bentgrass Variety Trial — August 31, 2023 by Shehbaz Singh, MS
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).
- Evaluate the establishment rate of each cultivar at green height.
- Evaluate the dollar spot susceptibility of each cultivar at green height.
- Evaluate the agronomic parameters and quality of each cultivar at green height.
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.
- To evaluate post broadleaf weed control in no-mow fine fescue.
- 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.
- Herbicide 1 (2 apps-one month apart @ 4pint/acre )
- Herbicide 2 (2 apps-one month apart @ 4 & 8 pint/acre)
- Herbicide 3 (2 apps-two month apart @ 4 pint/acre)
- Herbicide 4 (2 apps-one month apart @ 4 pint/acre)
- Herbicide 5 (2 apps-one month apart @ 4 pint/acre)
- 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)