SURVEY QUESTION

Sports Turf: Have you sampled for nematodes on your sand-based fields?

Yes - didn't find any
Yes - populations too low to be a problem
Yes - Have had damage from them
No - Probably should
No - Hogwash!

Update (6/4/2019)

The Raging 'Todes

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July 30: Full Field Day Schedule Release

Come join us for the 2019 Mizzou Turfgrass & Landscape Field Day to be held on Tuesday, July 30th at South Farms in Columbia, MO. The full schedule is complete, and with the new alternate year schedule includes a ton of great informational presentations. We even have to get started a little earlier to cram it all in. Twelve stops in the morning sessions followed by three specific seminars in the afternoon that will lead you through Jefferson Farms (Horticulture), calibration and lawn disease control in lawn care, and a tour of the MU athletic facilities for those in the sports turf realm. Also don't worry golf, we'll give you plenty to chew on throughout the morning with putting green management, technology, billbugs, weed control, etc. See the full schedule below!

Attendees, sponsors and exhibitors can all register by visiting https://extension2.missouri.edu/events/2019-mizzou-turfgrass-and-landscape-field-day.

A little different portal and login, but 2017 was so two years ago. We also still have the previous website to list sponsors and quickly update more detailed information - http://mufieldday.com.

Weather

Wasn't May Temps That Got Our Attention

  1. May temps ended just a few degrees above normal. - Missouri Climate Center
  2. 6-10 day outlook: Perhaps not a hot start to June. - NOAA

May temperatures were just a few degrees above the long-term average, and nothing to get too worked up about from a plant standpoint. Cool season lawns, roughs, sports fields, etc. are growing just fine this spring, perhaps too much so in some cases. This mild pattern thankfully looks is forecasted to continue into early June.

The real story is the rain. May 2019 may likely set the all-time record for wettest May, and if it doesn't it'll be a close second. The brunt of the precipitation has fallen in the west and southwestern portion of the state. Kansas City had the wettest May on record at 12.81 inches (a mere 7.59 inches above normal) and third wettest month for ANY month in 131 years of record keeping. All of this precipitation to the west and north in combination with the snowmelt has unfortunately resulted in intense and disastrous flooding in the region. This isn't just a problem for the traditional row crop farmers, but also is having implications on the turfgrass industry as noted below in regards to winterkill.

Rain, Rain Set to Go Away?

  1. North and western parts of the state heaviest hit with rain. - Missouri Climate Center
  2. 6 - 10 day outlook: Doesn't appear rain chances are likely to let up. - NOAA


Quick Hits

Brown Patch & Large Patch Active

  1. Look down at tall fescue and investigate for brown patch lesions near leaf bases.
  2. Large patch on zoysia seems to be chugging right on into June.

  • Lawns: Brown patch on tall fescue is starting to show, as lesions were found last week low in the canopy. In shaded or wet areas prone to this disease, pull back the leaves and look for the tell-tale lesions lower on the leaf blade near the leaf sheath. All of the rain this year has set a perfect environment for this disease, and if the temperatures do pop into the mid 80s and 90s during this pattern, this disease will explode along with it. If opting for fungicide applications, plan prevention in the next few weeks while temperatures are still moderate. With the constant precipitation and spring growth this year in tall fescue, monitor for nitrogen deficiency and consider a small 0.25-0.5 lb N/1000 sq ft application of fast release or even better slow release N source if chlorosis is noticed in older leaves.

    Large patch in zoysia is raging now in untreated areas. Stopping progression with a fungicide application may be necessary, but also encourage regrowth with a nitrogen application now.

Winterkill Apparent & Obvious

  1. Our 'Patriot' bermudagrass block incurred significant winterkill.
  2. Spring dead spot also acted as a winterkiller in areas that did green up.

  • Winterkill: This is by far the worst episode of winterkill I've observed in my time in Missouri, far exceeding that of the polar vortex of 2013-14. From one side of the state to the other, I've visited golf courses, sports fields, lawns, and sod farms that have experienced winterkill on areas ranging from localized to expansive. Even the winter sturdy 'Meyer' zoysiagrass has deceased in areas that were prone to standing water from lack of drainage or prolonged water/ice cover due to shade. Bermudagrass, even areas established with 'Latitude 36' and other newer cold tolerant cultivars are also struggling with winterkill issues. In the pictures above, nearly our entire plot of 'Patriot' bermudagrass has not greened up, except for small portion in the back which is getting torn up by purposed spring dead spot inoculations, and a small research plot with integrated and very green Kentucky bluegrass.

    A main difference between this year's event and 2013-14, is the water. The 2013-14 polar vortex killed through dessication. Open areas without snow cover felt the brunt then. This year the winterkill is associated with our wettest winter on record since 1984-85, that included several big swings in temperature and freeze/thaw cycles. In this case, 'Meyer' or other normally cold hardy varieties weren't just exposed to cold temperatures but also from anoxic conditions due to prolonged ice cover and saturated conditions.

    The other unfortunate aspect to this story in some of the region is the river flooding. In the farming community, these floods are resulting in a crisis situation, and MU extension is organizing quickly to assist where possible (see https://ipm.missouri.edu/IPCM/2019/5/floodingCornSoybean/). Several sod farmers are quite literally in this same boat, and may not be able to service warm-season sod needs for several more weeks until flooded fields dry out… if they do. At this point, patience is the only option.

Dollar Spot and Red Leaf Spot Pounce in Late May

  1. Dollar spot pressure spiked in late May, and is staying there.
  2. Red leaf spot also occurred on our research green. Inset: Drechslera erythrospila spore.

  • The Spots Are Alive: Dollar spot severity launched into overdrive at the end of May and will surely continue with this mild, wet weather pattern. Joining it late last week is red leaf spot on creeping bentgrass which we observed in one of our research trials. This disease is specific to creeping bentgrass putting greens and will appear as speckled brownish red areas that appear as if someone flicked gasoline or hydraulic fluid from their fingers. In reality, these diseases are fairly rare on golf putting greens because they are controlled well by a number of different fungicide classes including the SDHIs, QoIs, and dicarboximides.

Poa annua Problems

  1. Summer patch infection often occurs at base of root.
  2. Basal rot anthracnose occurs in the crown tissue.

  • Poa annua diseases: While we've only observed a few relatively minor bentgrass diseases, considerable damage is being reported and sampled on Poa annua. Many superintendents may exclaim "good!", unless this species makes up a large percentage of your putting green. Summer patch as observed on a course in western IL and anthracnose was observed on a green near Kansas City. As shown above, summer patch hits below the belt and will attack Poa roots and root bases. Conversely, basal rot anthracnose will most often dive into the leaf sheath and attack the plant at the crown. Remember anthracnose is a low nitrogen disease so bumping up the N can help suppress this disease in combination with topdressing and several other cultural practices outlined here (https://turf.rutgers.edu/research/bmpsanthracnose2014.pdf). While you're at it with the nitrogen, consider using ammonium sulfate or other acidifying fertilizer if the soil pH is high to reduce the potential for summer patch.

Nematode Impact on Turfgrass & Sampling

Nematode Sampling

  1. Damage by sting nematode on a 'Tifeagle' bermuda green in southern MO.
  2. The sting nematode is the most damaging at low populations due to its big stylet.

As a turf manager told me during a recent visit, "it seems that nematodes are all the rage these days!" While I don't think concerts from the Raging 'Todes will be selling out this summer, he had a point that it seems our consciousness of these critters has reached a fever pitch.

Now to make it clear, in Missouri and much of the region nematodes have only been found to be a problem on turfgrass in sandy soils. Since we are predominantly loam or clay in this region, this includes golf course putting greens and some sports fields constructed on a sand base. The reason for the sand-based rootzone is drainage, drainage, and drainage enabled by large pore sizes, which also unfortunately provide ample space for nematodes to migrate and reproduce. Also note that in both situations, the turfgrass needs to be mowed lower for playability which in turn reduces the root length and effective population of plant parasitic nematode that can be tolerated.

Several species have been found to be an issue in Missouri. Much to my surprise and the unfortunate demise of putting green health, sting nematodes (Belonolaimus longicaudatus) have been detected on several courses with bentgrass putting greens in Kansas City and now several ultradwarf bermudagrass greens in northern AR and southern MO. Due to its large stylet and aggressive feeding activity, this large nematode can do considerable damage at low populations (1-10 per 100 cc of soil) and in some instances over 200 were detected. As detailed in previous reports, we also have detected lance nematodes (Hoplolaimus spp.) the second largest plant parasitic turfgrass nematode that can feed outside the root or burrow itself inside. Some of these samples had lance in the thousands when the threshold sits in the hundreds.

We also have sampled a few sand-based sports fields in the past year, and surprisingly have found high counts of ring (3600 per 100 cc) and spiral nematodes (4000+ per 100 cc) in poorly performing areas. On sports fields, this population of ring nematode although above threshold wouldn't normally be of concern since the grass isn't mowed too incredibly short, but in combination with another nematode species well above threshold a reduction in root length and turf quality was apparent.

In something has seemed amiss or is going wrong now, a nematode sample is recommended, particularly since we now have some tools (i.e. Indemnify, Divanem, etc) to suppress nematode populations. If the problem is going on now and the area is relatively small, take a 4-inch deep cup cutter plug from the edge of the damaged area (not the middle) and one from a good performing area for comparison. If you are just checking across a larger area or if a larger area is performing poorly, take samples like you would for a soil fertility analysis. Use a zig zag pattern across the area and take 12-16 samples with a 0.75 inch soil corer and mix them together for a single sample leaving the verdure on. For more information on the MU nematode analysis service see https://scndiagnostics.com/nematode_testing/#hideTurfNem. If you would like me to see the results and discuss with you, please write a note on the sample submission form.



Lee

Lee Miller
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Extension Turfgrass Pathologist
University of Missouri