Turfgrass Scouting Report: April 7, 2019

Golf season has officially begun here at the Chicago District Golf Association golfers are starting to post scores and tournament registration has quickly filled up for this summer. While this is a welcome relief to what was truly an unprecedented winter many golf courses are lying dormant hoping for warmer temperatures to arrive. However, if we are to learn from last season this could be an unsettling month and a half. Almost every golf course in the region had their trials and tribulations last season due to the lack of cooperation from mother nature. The high temperatures, large rainfalls, and high dew points were not ideal for growing grass. But after talking with many superintendents and members for the industry the recurring topic was about how the spring of 2018 contributed to many of the difficulties faced throughout the summer and into the fall. As of now similar trends are occurring and even more alarming is that we may even be behind compared to last spring.

Weather

Differences in temperatures in 2018 and 2019 when compared to the 30-year average

I mentioned earlier that the temperatures we have experienced so far this spring and in particular the month of March have been very similar to those experienced in 2018. While there have been warmer days this year so far compared to last year we were significantly below average to start the month, and with very few days at or above average this has had a detrimental effect to our soil temperatures over the past month as well.

Soil temperatures well below temperatures compared to last year.

Soil temperatures are crucial in the spring in order for many plants but especially creeping bentgrass. Currently, many of our soil temperatures are hovering around the low 40’s at a 4-inch depth. Some courses near the lake are even cooler which is ultimately slowing the green up process down even further. These soil temperatures again are not ideal for creeping bentgrass activity. Various cultivars can be more active at cooler temperatures and are faster to green up in the spring. Some cultivars like L-93 are some of the slowest creeping bentgrass cultivars to green up as seen below.

L-93 creeping bentgrass still a long way from greening up.

While bentgrass is slowly growing this is giving Poa annua a significant advantage to out-compete bentgrass in certain areas. Typically creeping bentgrass becomes active when soil temperatures are between 55–60 F. Poa annua is able to become active at much cooler soil temperatures around 40–45F. The slow start to the spring could cause an explosion in Poa populations on many golf courses and for courses that have newly established bentgrass areas, this could be a major problem.

Growing Poa annua population in a creeping bentgrass approach

Meanwhile, for our friends down south managing zoysia grass soil temperatures are still a little ways off as well. The zoysia here in Chicago likely will not begin to green up until the end of May is the weather stays this way for the rest of April.

A dormant stand of Zoysia grass in Chicagoland

Weeds

Whether you consider Poa annua a weed or not entirely depends on your golf course, many courses in the area are managing Poa putting greens. One question which has come up over the past few weeks is Proxy/Primo applications in order to control Poa seedheads. Some courses have made at least one application this spring and many courses have made applications the previous fall. Right now much of central Illinois and the southern part of Chicagoland are in the target range to make these applications. Based on research conducted at various universities, controlling Poa seedheads the timing of these applications are important for successful control. Applications made in the fall and spring have been shown to have the most success, while applications made after the target growing degree days have shown little to no success. The take-home message should be that these applications are better off being made early than too late.

Most of Chicago and Northwest Illinois should fall into the target application period by early next week.

Another weed that can cause headaches for many superintendents is crabgrass. Preemergence applications for crabgrass control is closing in in the northern part of the state. Meanwhile, in central Illinois, these applications should be on the docket this week especially if crabgrass was an issue last year. The best way to control crabgrass is with preemergence herbicides. Post-emergence herbicides for crabgrass are available however selecting the right herbicide based on the growth stage of crabgrass can cause issues at times.

Preemergence applications for crabgrass should be on the schedule for this week

During my visits this week many courses are seeing significant moss activity especially on putting greens. For the most part, the activity seems to be more prevalent in the cleanup passes on the greens. Identifying moss on a putting green can be difficult at times depending on the moss and the color of your putting green. Sometimes we can see moss standing out due to the bright green color. Other times a darker color is more often seen and can be overlooked at times.

When all else fail a hand lens can help identify some of these areas. Controlling moss can be difficult and often requires chemical and cultural control options. Recently there was an article published in GCM written by Dr. Raudenbush which looks at these control options. See the link to read the full article .

Hand lens view of moss growing on a putting green.

Disease

For the most part, it has been a quiet start to the spring in the way of disease activity. I have seen some pink snow mold running around but only in locations where fungicides were not applied last fall. Many of these areas are not active and do not require fungicide applications for recovery. A little bit of nitrogen and some warmer temperatures these damage areas will grow out and recover.

Remnants of pink snow mold lingering around given the cooler temperatures.

I have looked a lot at soil temperatures and growing degree days in this scouting report and for our soil-borne pathogens, the same story applies. We are still pretty far out from these fungicide applications but it is never too early too start planning ahead especially if your course is prone to these diseases.

Any questions or concerns don’t hesitate to contact me,

Ron Townsend

rtownsend@cdga.org | (630) 685–2310 | CDGATurfgrassProgram

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CDGATurfgrassProgram

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