Localized Flooding! Unusually Cool, Leaf Spot, Broadleaf Weeds Surge, and Tee Research
It’s been a rough week weather-wise (severe thunderstorms), but otherwise we have good news. Dry conditions have largely disappeared and rapid turfgrass recovery has been experienced. Regular rain events are now the norm in summer 2023 — though it’s meant flooding for some. And then some tornado sirens on Wednesday, July 12 — never good and severe damage of 60–70 trees was reported by one Chicago course. Overall, this growing season has advanced in fits and spurts. Three distinct phases so far, but who’s counting? 1) Overly Cool: During spring, a dry April surprised us with overly cool temperatures which effectively halted normal growth of creeping bentgrass. 2) Very Dry: Summer began with conditions of severe drought for a majority of Illinois. 3) Big Rains: In early July, the first deluge of heavy rain was experienced in northern Illinois with flash floods since.
Near constant rain has meant signs of fungi (mushrooms) are everywhere. In the landscape, just like that, browns have quickly faded/disappeared. Daylilies, Hemerocallis, are now seeing peak bloom. In similar fashion, turfgrass is growing fast and looking lush. Given the drought we’ve just experienced, such rapid recovery has been jaw-dropping. Best of all, most of us get to enjoy it with minimal effort. Take Home Message: From lawns to golf courses things have greatly improved. It’s what the summer season can (but doesn’t always) bring the outdoors. So go out and enjoy the game of golf during near optimal conditions via a cool July. Be amazed at nature’s resiliency (given rain) and appreciate the efforts of those who maintain.
Report of Leaf Spot of Creeping Bentgrass
Leaf spots are normally associated with cool conditions of the spring and fall seasons. However, midsummer 2023 has been a bit abnormal temperature-wise. We are currently experiencing night temperatures which are unusually cool for mid July. Ranging from 50s to 60s with high humidity and frequent rains. Multiple fungicides are labeled for leaf spot and offer good control. Be aware that leaf spot pathogens have been associated with fungicide resistance. A good example of why it's necessary to rotate different modes of action with regard to fungicide programs.
Featured Weed: White Clover, Trifolium repens
Did you notice? One broadleaf weed is now shining (flowering) above the rest. It is white clover. As a legume, clover can fix its own nitrogen and this unique advantage makes it competitive across a broad range of environments, soil types and turfgrass species.
We are seeing more white clover this summer. It probably has to do with the drought just experienced (May and June). The dormant turfgrass areas were not as competitive versus white clover. White clover continued to grow relatively unfazed. Just about as bullet proof a plant as it gets.
Research has looked at mixed stands of clover and turf. A recent example found is by Bigelow et al., International Turfgrass Society Research Journal, 2020. Cool-season lawn performance as influenced by ‘Microclover’ inclusion and supplemental nitrogen
Tee Research — July 12, 2023 by Shehbaz Singh, MS
All tees were evaluated this week — part of a monthly scientific evaluation of greens, fairways, and tees at Bob Berry Sunshine Course in Lemont, IL.
Investigations evaluate playability, agronomic characteristics and quality. The tees are currently in their third year of establishment after renovation. Surfaces consist of five turfgrass species that include; creeping bentgrass, colonial bentgrass, Kentucky bluegrass, perennial ryegrass and tall fescue.* *Tees were renovated in 2020 by Wadsworth Golf Construction Company.
As before, data was collected in three parallel lines on the tee surface. Readings were then the averaged across each of the three lines. The following four parameters were evaluated:
1. Visual Quality (1–9 scale with 9 best and 6 = minimum acceptable)
2. Normalized Difference Vegetation Index (NDVI) was measured using GreenSeeker by Trimble.
3. Weeds (%) were visually estimated around each point in about area of a 5 ft radius circle.
4. Localized Dry Spot (%) was visually estimated around each point in about area of 5 feet radius circle.
Additionally, four sampling points were selected (four corner points of a 10 ft square in the center of each tee). Any future investigations on (parameters 5–8) each tee will be conducted in the close proximity of selected points on the tee.
5. Root length (in) was measured taking the average of four 0.5 inch diameter soil samples (maximum root length).
6. Thatch (in) was measured taking the average of four 0.5 inch diameter soil samples.
7. Shear Strength was measured using Shear Strength Tester by Turf-Tech International Inc.
8. Root Length (in) was measured as the average of four 0.5 inch diameter soil samples (maximum root length).
9. Root-Feeding Nematodes (number per 100 g soil) were extracted by lite sucrose centrifugation (upper 2 inches of four soil cores).