Virginia Turfgrass Council – Year in Review•2018 – The Year That Seemingly Will Never End for Turfgrass Managers
Virginia Turfgrass Journal – From the Virginia Tech Turf Team: Mike Goatley Ph.D., Shawn Askew Ph.D., David McCall Ph.D., Jeff Derr Ph.D., Tom Kuhar Ph.D., Jordan Booth
The VT Turf Team prides itself on finding and providing answers or at least a novel approach to try when it comes to the challenges that Virginia’s turfgrass managers face year in and year out in the transition zone. Unfortunately, this year we had to face the facts — the challenges were too many in 2018 regardless of location throughout the state or what grass was being managed. The weather since late-December 2017 has been as difficult and frustrating for our industry as any in recent memory.
Years like 2018 in the Mid-Atlantic region are not normal. After all, the “normal” temperature and moisture data are just summarized over a few decades to arrive at a “normal” average of abnormal years! Let’s look at how Mother Nature was “signaled for piling on” turfed sites in the mid-Atlantic in 2018.
Seasonal stress is not uncommon in the Mid-Atlantic. Virginia lies in the climatic Transition Zone. A 200-mile plus zone between where bermudagrasses are more truly adapted in areas to the South and where cool season grasses are more truly adapted in the cool humid regions to the North. In the transition zone, most turf grasses require more persistent and skilled management to persist. Management highlights practices that attempt to make up for the potential negative impacts of cold winters or short seasons on the warm season grasses and the hot, humid summers impacting the cool season grasses. Colder winters and cooler than normal and/or shortened growing seasons are hard on bermudagrass and other warm season grasses. In warmer than normal summers, the cool season grasses (creeping bentgrass, Kentucky bluegrass, perennial ryegrass, tall fescue and the troublesome annual bluegrass) experience significant heat and drought stress. Expert management is needed every year in the transition zone since grasses we use in fine turf can have different stresses each year.
The primary stress factors in 2018 included 1) winter kill and a delayed spring green up (bermudagrass and St. Augustinegrass); and 2) excessive rainfall (all grasses).
How was 2018 different? Virginia had weather extremes that were well beyond the norm in 2018. In southeast Virginia, there were six days in January when the minimum temperature was below 20o F based on data from the Norfolk airport, including two days when the low was 10o F. The average low is 32o F. In February, there were 12 days when the high temperature was over 60o F, while the average high is 51o F. In March there were five days when the low temperature was below 32o F. In October there were 11 days with a high over 80o F, while the average high is 71o F. This was quite a roller coaster of temperatures for late winter and early spring, combined with above average temperatures in October.
The 2018 Impact on Bermudagrass and St. Augustinegrass: We in Virginia are used to the occasional unpredictable cold winters that result in bermudagrass winterkill every 7 to 15 years or so. This past winter was one of those years for winter kill across much of the mid-Atlantic and Southeast. There was a massive bermudagrass winterkill problem statewide, plus winterkill of St. Augustine in southeast Virginia. Yet summer-like conditions necessary for bermudagrass spring 2018 regrowth and replanting was delayed at least a month. That delayed the unmasking of bermudagrass winter kill and recovery strategies until after the delayed spring greenup. This also shortened the bermudagrass growing season. We came out of winter with weaker and dead areas of turf.
The 2018 impact on cool season grasses
Cool season grasses had a number of stresses working against them during the summer months and late into the growing season. Besides the “normal” heat and moisture stress of the transition zone, 2018 was wet. Ask any turf manager what stresses they need to control to have a good year, and they will tell you number one is water and soil moisture! Experience matters in such a wet/stressful year. Yet when was the last year that hit us like this one? There is little in the manager’s tool box to remove the effects of excess water. All that can be done within Best Management Practices involve having adequate surface and internal drainage. This is much like investing in real estate where it is all about location, location, location; in turf it is about surface and internal drainage, drainage, drainage!
In 2018, even sites with the best designed drainage may have also had problems since this was a year of prolonged rainfall patterns that repeatedly saturated soils. Plant roots need soil air (aeration) to be healthy; to take up water and nutrients. The plant can then continue to grow and cool itself (transpirational cooling) during high temperature stress. Excessive soil moisture interferes with these plant functions. This is more problematic on unmodified native soils with poor surface drainage. Sand modified sports turf and putting greens designed with both surface and internal drainage have a real leg up on areas that do not. Instead of irrigation water being judiciously managed during dry-down periods in a “normal” summer, rainfall was unrelenting in frequency and amount, making soil moisture uncontrollable on many turf sites.
Additionally, no two turfgrass sites are alike when it comes to inherent turf, soil and microclimate that combine to impact turf quality. Those impacts are often magnified when multiple plant stresses combine to threaten turf quality and performance. So, turf damage can vary greatly with each property or with areas contained within one property.
The main factor that set up a number of pest issues was uncontrolled soil moisture from excessive amount and periods of rainfall.
The efficacy challenge of plant protectant chemicals in 2018.
There simply was a lot of dilution and hydrolysis (the chemical breakdown of a compound due to reaction with water) of our chemistry due to the abundant amount and frequency of summer rainfall. Thus there were massive breakthroughs in weed populations, and recurring instances of just about every spring, summer, or fall disease that we can experience in Virginia.
Fungal diseases were worse than in a “normal” year – three contributing factors:
1) On areas where fungicides were not budgeted and not treated, turfgrass disease damage was likely greater from microclimate favoring disease outbreaks.
2) In areas where soil moisture was excessive, the fungal disease problems were greater due to a weakened plant.
3) Higher night time temperatures for prolonged periods in 2018 “piled on” to favored fungal disease activity.
In 2018 we also were still seeing Pythium and Brown Patch in golf, sports turf, and home lawn settings well into October. Turf managers that normally breathe a sigh of relief when Labor Day finally arrives, bringing with it anticipated night time temperatures that finally consistently get into the 60s, didn’t really start experiencing the cool night temperatures until Columbus Day (October 8th) in 2018. One constant theme around the mid-Atlantic wasn’t that our temperature extremes were so high, but that our nighttime lows were some of the warmest on record. There certainly wasn’t a lot of this until well into October this year. The combination of continuously warm and wet soils led to some of the worst Pythium root rot outbreaks that we have experienced in many years.
Problems persist even into November. Cool-season grasses that have been seeded this fall have struggled mightily with the excessive moisture that we have received. Saturated soils and high relative humidity are great for germination, and equally great for lots of seedling damping off diseases too. Great looking stands of tall fescue and ryegrass over-seedings have emerged and essentially evaporated this fall due to seedling diseases.
Weed control in a wet 2018 was less effective – three contributing factors.
- In areas treated for summer annual grasses with pre-emergence herbicides the control period may have broken down sooner than in a normal year due to herbicide breakdown in warm wet soils. The result was more noticeable crabgrass and possibly goosegrass by mid-summer and year’s end.
- The greater soil moisture likely enhanced weed seed germination as opposed to that of a normal growing season where irrigation is deep and infrequent and then soil beneath the turf is not continually moist as in 2018. We’re already seeing bumper crops of winter annual weeds around Blacksburg this year, and remember that if you are planning on controlling them, earlier is better than later. However, you also need to be careful in your herbicide selections if you are still trying to get seed established.
- Weeds are naturally going to be able to take a foothold due to lack of competition from a healthy turf in areas of thinning and dying turf. Turf is thinned and “opened up” due to 1) heat stress from wet wilt (excess moisture stress); 2) fungal disease activity; 3) greater thinning from traffic and wear; and 4) thinning from insect activity (armyworm, white grubs, annual bluegrass weevil; etc. ). Thin turf entering autumn opened up the turf for winter annual weeds as well.
Damage from Insects and Nematodes in 2018
There was greater pressure from army worms in the late season that defoliated many turf sites. Virginia was hit with two other insect pests that took the headlines in 2018. First, annual bluegrass weevil (ABW) populations showed up in damaging levels on a number of golf courses around the Commonwealth, injuring both annual bluegrass and creeping bentgrass fairways, collars, and tee boxes. This insect will probably be here to stay now, and Virginia will be a full-fledged participant in Weevil Trak with new locations planned for Blacksburg, Roanoke, and Richmond in 2019 to help monitor the life cycle of this pest and advise turf managers on proper control recommendations.
Fall armyworms made their way to Virginia after the storms in the fall. This insect was causing problems in the Carolinas from mid-summer forward, and when they arrived in Virginia, they showed up in mass! Numbers were so large that even bermudagrass fairways and sports fields were being defoliated. There was even a scare of it possibly showing up in masse at Lane Stadium just in time for the big Virginia Tech vs. Notre Dame football game. The armyworms did not show up, and unfortunately, neither did the Hokies defense!
The often-forgotten plant-parasitic nematodes have become increasingly problematic on putting greens. While high populations can cause problems alone, the combination with such miserable growing conditions intensifies the problem. One Richmond-area superintendent summed the problem up best when he explained that the turf “just won’t respond” when nematodes were preventing recovery.
Other factors contributing to turf stress in 2018
Algae – a common issue at soil surfaces in wet years that can impair air exchange into the soil.
Drainage – stated earlier but worth repeating as a major issue! The lack of surface drainage for excess rainfall results in less efficient root function, a lush and disease-prone turf with less wear tolerant grass canopies.
Less drying down of turf/soil systems between rainfall events. Air movement associated with drying of soil and turf canopies is needed for healthy turf. Turf sites often remained wetter for longer time periods (days) especially in shaded or wind-blocked sites, resulting in extended periods of moisture and the issues that are aligned (enhanced disease, weak turf, greater soil compaction).
Higher relative humidities common with relentless weather patterns of repeated rainfall make it harder to dry down soil/turf systems and contribute to greater disease, less turf vigor (weak thinning turf) and greater soil compaction.
Mowing. Greater mowing frequency is needed, but often difficult to achieve in wet soils. This may necessitate less frequent mowing, resulting greater turf stress.
Traffic and wear. Greater soil compaction occurs from foot and vehicle traffic in moist soils
Reduced sunlight reaching turf. The lack of sunlight was further compounded in shaded situations that resulted in algae blooms and disease pressure that had never been seen of that magnitude.
Where to go from here?
There are no easy fixes for any of these situations, but it certainly emphasizes the importance of both drainage and sunlight while providing an opportunity to revisit this with your clientele regarding the need to improve the environment in which you are trying to grow grass.
Re-establishment planting and fertilizer. Soil temperatures in early November were still at or near 60o F in many locations, so seed germination was still possible, but every day that passed put us one day closer to winter and one less day for establishment to take place. There aren’t a lot of inexpensive solutions to these challenges either. Germination cloth will certainly help improve both moisture and soil warming, but it comes with its own cost of product and installation and removal. A compost application can help by providing a dark surface to absorb and radiate a little more of the sunlight, so where conditions permit, consider a 1/4 inch depth of compost over new seedings in order to prolong germination periods as long as possible. With our warmer soil temperatures, it also makes sense that our fertilization window was extended in 2018 further into November. Never apply fertilizer to frozen soil and keep the rate at no more than 0.7 lb N/1000 sq ft/growing month level in mind, but for a year like this, don’t lock into a calendar date because Mother Nature has obviously not been paying attention to a calendar.
2018 was an excellent year to revisit and identify drainage and shade issues in just about every turf situation imaginable. In years like this, any limitations in surface drainage are exaggerated. We even had synthetic turf fields fail in northern VA because of their inability to properly drain the amounts of water being received.
Plan now for your recovery strategies this spring and even beyond for summer of 2019. Dr. Dick Schmidt always reminds us that based on many years of his research (continued by Dr. Xunzhong Zhang here on campus) that these are exactly the types of situations where we can incorporate more of our supplemental turf management approaches with biostimulants, humic acids, seaweed extracts etc. into the program. They are not replacements for sound management, but they are valuable tools to implement. For some, the solution is sod, but even sod crops and installations had challenges this year from both the environment and pest pressure.
The bottom line is that once November arrives, winter is inevitably approaching and there simply aren’t enough growing days left to expect great things from newly established cool-season grasses. And given the weakened conditions of most of our grasses (warm or cool-season) pay particular attention to stresses that arrive this winter. A bermudagrass manager from Tidewater sarcastically said the other day “you watch and now we’ll have another dry winter where desiccation is a problem”. That’s definitely something to pay attention to as it no doubt was a big part of the loss of warm-season grasses last year.
So, fellow turfgrass managers, you no doubt deserve a break, but Mother Nature simply doesn’t care about how difficult it has been. As instructors, the VT Turf Team is constantly reminding its students that the easy part of the job is growing the grass, and the challenges are with money and people. Well, even the grass growing hasn’t been easy this year, but it now gets really interesting trying to explain your challenges to a public that wants results and readily forgets how often you’ve provided an excellent turf. It’s not much consolation but every situation is an opportunity to learn something or improve upon – consider what an opportunity you have really hone your communication skills in convincing your clientele “it’s not my fault”.
And this time, you’re probably 100% correct.READ THE ISSUE