Summer Heat Breaks: Dollar Spot, Brown Patch and Sand Bunker Research

Image 1. A nice lesson of mowing height use in turfgrass management. Each one is impactful depending on your perspective (design, maintenance, aesthetics and play). Ridge Country Club, Chicago. Settle, Aug 11, 2022
Image 2. NOAA seasonal forecast (Aug-Sep) for normal rainfall in the Midwest is a flip of a coin (50/50 chance). Compare that to the Mid-Atlantic region where they may see greater than normal rainfall. More info here

by Shehbaz Singh, MS

North Chicago, Glenview: The air temperature in northern Chicago suburbs ranged from 56 (lowest low) to 95 °F (highest high) over the period of last seven days. Higher air temperatures were recorded early in the week. Temperature highs ranged from 83 to 95°F and the highest air temperature was experienced on Aug 7 (Saturday). Temperature lows were generally higher than normal and ranged from 65 to 74°F. As the week progressed, air temperatures became milder. The relative humidity was quite higher during the last seven days and it ranged from 78 to 95%. The cumulative rainfall for northern Chicago suburbs was about 0.5 inch over seven days. For example, moderate rainfall of 0.25 inches fell on both Aug 7 and Aug 8 in Glenview.

Figures 1 and 2. Weather conditions during the second week of August. North Shore Country Club, Glenview, IL

Dollar Spot, Clarireedia jacksonii

Peak disease pressure of dollar spot was first encountered approximately a month ago. Well it returned this week when it felt more like Seattle, Washington that Chicago, Illinois. Two dollar spot studies tell the story. They both use a randomized complete block design. Each study is replicated 4 times.

Image 1. Dollar Spot vs Greens: We just experienced our second jump of dollar spot disease pressure on a creeping bentgrass nursery green (L93 plus Providence). The first jump occurred between rating dates of Jul 13 to Jul 18. The second jump occurred between rating dates of Aug 1 to Aug 9. North Shore Country Club, Glenview, IL. Settle, Aug 9, 2022
Image 2. Dollar Spot vs Greens: A treatment with good efficacy versus dollar spot, North Shore Country Club, Glenview, IL. Settle, Aug 9, 2022
Image 3. Dollar Spot vs Greens: A treatment with poor efficacy versus dollar spot, North Shore Country Club, Glenview, IL. Settle, Aug 9, 2022
Figure 1. Dollar Spot vs Greens: Dollar spot progression of two dollar spot studies on a creeping bentgrass nursery green in 2022. Two big jumps in the studies coincided with optimal conditions in summer for disease development; warm nights (70s F) + extended periods of leaf wetness (10 hours or more). North Shore CC, Glenview, IL

Brown Patch, Rhizoctonia solani

Brown patch development occurred throughout Chicago this week. We observed brown patch for the first time in a study that is looking at nematode control. The study uses a randomized complete block design and is replicated 6 times. A newer experimental may also provide suppression of brown patch when applied every 14 days or every 28 days.

Image 1. Brown Patch: Identifying brown patch damage (foreground) on a creeping bentgrass practice tee. North Shore Country Club, Glenview, IL
Image 2. Brown Patch: Rating percentage of brown patch damage within a 4 ft by 4 ft treatment plot on a creeping bentgrass practice tee. North Shore Country Club, Glenview, IL
Figure 1. Incidence of brown patch in a nematicide study on a tee box. Applications were made every 14 days (Jun 13, Jun 22, Jul 13, Jul 25) or every 28 days (Jun 13 and Jul 13) at North Shore Country Club, Glenview, IL.

Sand Bunker Research by Shehbaz Singh, MS

At Bob Berry Sunshine Course in Lemont, there are three different types of bunkers. A brief information on all these bunkers are as follows:
1. Capillary Concrete. This bunker liner is constructed according to capillary concrete bunker system. Bunker liner base is developed using a specially formulated mixture of acceptably sized aggregate, various proprietary additives and water. The final product is known as ‘capillary concrete’.

  • Capillary Concrete liner depth is 2 inches
  • Bunker contains 4 inches of white sand known as ‘Best Signature’
  • Better Billy Bunker liner depth is 2 inches
  • Bunker contains 4 inches of white sand known as ‘Pro Angle’
  • Flexxcape represents a new generation of fabric-type liner
  • Bunker contains 4 inches of traditional colored sand known as ‘Pioneer’
Figure 1. Within each sand bunker differences in firmness existed (redder colors = less firm). Trends between each sand bunker showed bunkers A and B were similar and firmer than C. This is a non-replicated study and the results of C may be influenced by site conditions. Bob Berry Course, Lemont, IL
Image 1. A FieldScout TruFirm meter was used to collect data within each sand bunker. Settle, Jul 28, 2022
Figure 2. Within each sand bunker differences in moisture existed (Greener colors = wetter). Trends between each sand bunker showed bunkers B and C were similar and drier than A. This is a non-replicated study and the results of C may be influenced by site conditions. Bob Berry Course, Lemont, IL

Final Photo

Close up of panicle hydrangeas or H. paniculata in peak bloom. Settle, Aug 12, 2022

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CDGATurfgrassProgram

CDGATurfgrassProgram

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