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USGA Green Section Mid-Continent Region

Food for Thought this Fall

By Ty McClellan, Agronomist

Updated October 19, 2009

The weather in 2009 for the upper Mid-Continent Region will be recorded as one of the coldest and remembered as one of the oddest. Other than a 12-day stretch of intense heat during mid-June, temperatures were well below normal. In fact, only a handful of days reached 90°F in the Chicago area and very few areas in the upper Mid-Continent Region hit 100°F. When elevated temperatures did develop, they were short-lived and/or quickly offset by cool nighttime temperatures. Rainfall was plentiful and often timely. All told, environmental conditions mimicked those of the Pacific Northwest rather than the Midwest.

Given these non-typical summer conditions, cool-season turfgrasses experienced much less stress while the warm-season turfgrasses lacked vigor, as their growth was slowed much of the year by cooler temperatures and frequent rainfall. For all turfgrasses, disease development was rather minor when compared to more typical summers. By all appearances, this was a relatively easy summer for turfgrasses and their managers; however, there were a number of shortfalls observed this year. Before falling victim to a false sense of security, areas needing special attention as we transition into fall are detailed below:

• Completion of Earlier Projects - One of the wettest springs on record for the upper Mid-Continent Region did not favor those in the midst of course projects earlier this year. Whether work was performed in-house or contracted out, projects were delayed, if not abandoned, as even two consecutive days of favorable weather proved elusive. On the other hand, growing conditions were quite favorable for cool-season turfgrass (especially in the rough) all year-long and, with frequent rainfall, additional labor was needed to keep up with mowing. This limited the availability of labor for course projects. More often than not, spring projects either did not get finished or they persisted into the primary golfing season, inconveniencing golfers and interfering with routine daily course maintenance.

Looking forward, projects that went uncompleted (particularly if critical) will need to be readdressed. To do so with the typical number of full-time employees may result in other delays, as the unfinished projects take precedence over those originally planned for this winter. In other words, without additional winter staff to get the schedule back on track, projects previously planned for this season may need to be postponed until the projects from last season are completed.

• Adequate Budgeting for Fungicides - Mild temperatures correlated to an overall reduction in disease outbreaks in 2009 and the amount spent on fungicides followed suit. Superintendents generally reported anywhere between a 15% and 35% reduction in fungicide use this year when compared to previous years. While courses can count themselves lucky this year (and maybe even last year), this year’s fungicide expense should not be used when establishing next year’s budget, since it was not a true indication of typical disease pressure or the subsequent budget needed for control. It will be important to keep in mind typical use and needs.

• Irrigation - Cool temperatures and timely rains for most of the golfing season meant much less irrigation than normal. In fact, many superintendents in the Chicago area reported using their irrigation systems less than five times during the entire year for the purposes of replenishing soil moisture to appropriate levels. Rather, most used irrigation to simply water in chemical applications or lightly syringe ‘hot’ spots. As such, this year was very kind to those with inadequate or poor irrigation systems, who pay for water, or who have poor quality irrigation water. Unfortunately, this has caused some to lose sight of the need to improve the irrigation system, accurately budget for future water use, or support additional practices to manage problems associated with poor water quality, such as increased aeration, flushing and applications of gypsum, lime, calcium, etc.

• Organic Matter Accumulation on Putting Greens - Organic matter in putting green root zones increased this year, even for those with well-designed sand topdressing and aeration programs. Soil temperatures simply remained too cool for much of the year and putting green root zones were oftentimes waterlogged given regular, if not record-setting rainfall. Basically, cool soil temperatures caused soil microbial activity to slow and thus, limited its ability to decompose organic matter. A wet spring also meant the soils remained very saturated, thus limiting oxygen levels in the root zone that slowed oxidation, i.e. natural aerobic decomposition, of organic matter. To further complicate matters, routine topdressing applications throughout the growing season were difficult to administer given frequent inclement weather, so less sand was applied less often. To account for the increase in organic matter accumulation, an even greater emphasis should be placed this fall and next spring on core aeration and incorporating more sand into putting green root zones.

• Poa annua Control – Given that this summer was more like that of the Pacific Northwest, overcast skies combined with cooler temperatures and frequent rains that created environmental conditions very favorable for Poa annua. As such, decreasing Poa annua populations found in creeping bentgrass putting greens and fairways was very difficult this year. A lack of mid-summer heat meant that the Poa annua did not decline, and selective herbicides, such as Velocity, or plant growth regulators with some known levels of Poa annua suppression, such as paclobutrazol (Trimmit) or flurprimidol (Cutless), were not as effective. Looking forward, greater success should be anticipated in the future with a return to more typical summer weather.

If you would like more information about a Turf Advisory Service visit, do not hesitate to contact either of the Mid-Continent regional offices: Ty McClellan at tmcclellan@usga.org or (630) 340-5853 or Bud White at budwhite@usga.org or (972) 662-1138.

This week historically brings the first opportunity for frost in a good portion of the state. Fortunately, that doesn’t necessarily mean the terminal end to the growing season for our cool season grasses, unlike many other plants and crops here in Iowa. Frost formation can come in
many levels of severity affected by environmental factors such as low temperature, dew point, relative humidity, wind speed, cloud cover, and elevation. Turf managers only slightly control a few factors such as irrigation and moisture availability, applications of wetting agents, and cutting heights of the turf. Frost formation on turfgrass will begin or advance the entrance into dormancy as the plants prepare for the winter months. Though, the main concern that is always on the mind of the turf manager is damage to the plants due to traffic on frost laden turf. This can be a concern on all turfgrass areas, but especially on grass such as on golf course greens.

Pictures of traffic damage on frosted turf by Zac Reicher, Purdue University

Light frosts that are essentially frozen dew on the upper leaves of the turfgrass plants as the temperature approaches 32 degrees. This typically occurs close the coldest point of the night usually around sunrise, or in golf course terms right when you would like to mow. As the ice forms on the plant it begins to freeze the plant cells in the tissue of the turgrass leaf. This weakens the cells and makes them vulnerable to permanent damage, kind of like cracking an egg. In general, most damage primarily occurs on the leaf tissue, but in heavier frost events and on lower mowed turfgrass the damage can extend down into the crown. If the frost traffic occurs and cells near the growing point are damaged, the plant could be a complete loss.
This issue of the frost setting in causes not only delays in your maintenance system, but delays in golf play or other turf activities. The key is that time is money. So, we all want to limit the time our employees are at the shop, or golfers are holding up tee times, etc.
What can we do to limit these time delays? One practice that is commonly used is a light irrigation cycle which contains water that is warmer than 32 degrees to melt off the frost and warm up the surface. The issue with this is that it must be timed properly to not form more ice on the system. The other thing to remember is that the irrigation will only knock the frost off of areas it can reach, so cart or foot traffic damage can occur leading to the irrigated areas.
I have included a chart referenced from a past issue of Horticulture Home and Pest News authored by Richard Jauron. As you will see the data is somewhat dated, but after conversations with State Climatologist Harrry Hilaker the fall dates still are very accurate. The spring dates and growing degree days may change slightly.
 

As with all issues involving the weather it is hard to tell what might actually happen. Good luck finishing up the growing season!

Neric Smith,
Commercial Horticulture Program Specialist
Iowa State University Extension