Buckeye Turf Newsletter (Spring 2026)

By Tyler Carr, Ph.D.

Welcome to the Spring 2026 edition of the Buckeye Turf Newsletter, a quarterly publication from turfgrass science faculty, staff, and graduate students at The Ohio State University. We hope you find this newsletter impactful for your turfgrass operation. The articles we write are based on feedback we receive from you, so please complete the survey to let us know how we are doing and to suggest future article topics.

OSU Turfgrass Research & Education Field Day

Mark your calendar to participate in our field day on August 4, 2026. The event will be held at the Ohio Turfgrass Foundation Research & Education Facility in Columbus, OH.

More details here

By Tyler Carr, Ph.D.

In the spring, sports field playing conditions can change daily, thanks primarily to up-and-down temperatures and routine precipitation. Early in a week, a field can be dry, but sports field managers (SFMs) may notice bird baths during their morning walk following an overnight thunderstorm.

The problem isn’t just mud. Turfgrass coverage declines 4 times faster in wet soils relative to dry soils. This is experienced most as athletic field use is ramping up in April–June, which are the months when Ohio experiences the highest monthly rainfall. On athletic fields, the primary solution to this excessive moisture is drainage, drainage, drainage.

When water hits a sports field, it can either infiltrate into a soil or move laterally to the lowest point. The typical fine-textured native soils in Ohio are notorious for holding water. Water generally moves through these soils (percolation) relatively slowly, so we often see wet surfaces persist for many days following a heavy rainfall event—especially if environmental conditions are not conducive for accelerated drying.

Since native soils often retain moisture for prolonged periods and we have no control over Mother Nature, our most effective solution to move excessive water away from a playing surface is surface drainage. If your field struggles with low-lying areas that retain water, you’re not alone. SFMs will often apply soil to the low-lying areas to match surrounding grade.

I prefer to use a screened topsoil that closely matches the soil texture of the existing rootzone. Some SFMs will apply sand instead of topsoil; however, I generally only recommend this if you are going all-in on a 4–6-inch sand cap. Otherwise, the coarse-textured sand over a finer-textured native soil results in a temporary water table, which can negatively affect root development and turfgrass performance under water deficit stress. If the soil is added in a single application that would “bury” the turfgrass and prevent light exposure, I recommend first removing the existing turf to prevent soil layering, adding the soil and allowing it to settle, then re-establishing the turf from either seed or sod. If renovation is not an option, topdressing topsoil in 0.25-0.5-inch “lifts” can improve grade over time.

When discussing internal drainage, most immediately picture trenches and drainage pipe. However, any mechanism to improve vertical movement of water through the soil profile is considered internal drainage. Below are three separate internal drainage solutions, presented from least to most disruptive.

Deep tine aeration (solid or hollow tine) is often effective at generating deep channels for water and air movement. Most sports field managers will deep tine aerate at 1-3 inches deeper than their typical aeration depth. Always be mindful of the depth of your irrigation system when considering deep tine aeration.

Linear, sand-filled trenches can be created at a depth of 6-10 inches, accelerating vertical movement of water through a soil profile. These channels are generally 1-2 inches wide and spaced 10-20 inches apart. Many rhizomatous or stoloniferous turfgrass species will grow laterally to cover the sand channels.

The most disruptive (and expensive) of the drainage options in this article is the installation of drainage pipe. Pipe sizing, depth, spacing are dependent on soil texture, slope, local climate conditions (e.g., rainfall patterns). Gravel generally surrounds the pipe, which is then backfilled with a coarse sand that extends to the soil surface.

Good drainage doesn’t just prevent puddles…it protects turf, improves player safety, and keeps fields playable so they can best serve the communities in which they reside.

By Todd Hicks

The 2026 turf season is getting ready to kick off as I write this article in March. Some turf managers have already been out for their first mowing others are still trying to dry out and find a weather window to begin the season. Ohio has finally had a somewhat normal winter with cold temperatures and a fair bit of snow. With that in mind, here are the diseases I would be on the lookout for this spring.

The first problem I have already seen and heard about from turf managers is snow mold. This is not a real surprise due to our winter weather pattern. Ohio can experience both pink and gray snow molds. Most, if not all the reports I have seen so far have been the more common pink snow mold. Snow mold is active at temperatures just above freezing in moist conditions. The gray snow molds (Typhula incarnata, also called Typhula blight, and Typhula ishikariensis) most often occur when snow cover exceeds 40 to 60 days. Pink snow mold (Microdochium nivaile), however, does not require any snow cover to develop. The freezing and thawing of snow on grass, plus excessive ice buildup, is the major cause of snow mold and can cause winter damage to turfgrasses. Bentgrasses and Poa annua are especially susceptible to damage, but all cool-season grasses can be affected. Pink snow mold, which is probably the most common snow mold found in Ohio, circular patches of pinkish orange to brown infected turf are common symptoms. Typhula blight symptoms appear as circular areas of straw-colored to grayish-brown turf. The turf may also appear matted, with the appearance of a grayish-white mycelium at time of snowmelt. The mycelium often dries and becomes encrusted over the patch. If damage from gray snow mold is present, little can be done to undo the damage, so your focus should be on recovery. To help determine the extent of damage, take samples of affected turfgrass and bring them into an environment that is conducive to growth (warm temperatures and light). To assess potential turf recovery, observe the growth of the plants, watching for the development of new shoots. I would recommend photographing and documentation of the process to demonstrate the potential recovery of the turfgrass.

• Remove snow and ice from turfgrass areas (this is easier said than done).
• Lightly rake the grass to promote air circulation and to allow light to penetrate the canopy and encourage new shoot and leaf develop.
• If there is any dead or matted material, rake and remove it. In the case of dead turfgrass, renovation of the site would be recommended as soon as possible.
• If the site did not receive appropriate fertility in the fall, a modest application of starter fertilizer would be recommended.
• For gray snow molds, the damage is done, so fungicide applications are of little to no benefit at this time. In the case of pink snow mold (or microdochium patch, the common name for the disease when it occurs without snow), fungicide applications may be recommended, especially if wet conditions are experienced during the spring. Some fungicides to consider for pink snow mold would be fludioxonil, iprodione + chlorothalonil, iprodione, propiconazole, pyraclostrobin, thiophanate-methyl or trifloxystrobin.

The next problem that I would look out for is leaf spot. This has been responsible for the most samples I received the last 5-6 years running. This problem (Drechsler & Bipolaris spp.) affects both short and high-cut turf managers and is not prejudice as to what species of turfgrass it affects.

Last year we saw a widespread thinning of turf no matter where we were or what type of turf we were looking at. The problem was compounded by the fact that leaf spot likes both warm and cold weather patterns, it just needs wet weather. This disease is also a great chameleon, its patterns seen on the turf can mimic other diseases quite well. If in doubt when diagnosing your problem, always seek help. Whatever chemistry has been working for you in the past fighting leaf spot should be fine again this year.

The next big threat on my list for this year is Anthracnose. As in most cases, preventative spraying keeps this problem at bay and is the best way of heading off this problem. There is an information sheet about Anthracnose Basal Rot on greens, key management tools and fungicides here.

My last helpful hint is if you are not already, you might want to start a phosphite program. This group of fungicides is our only true systemics, provides some disease control, and provides agronomic “benefits” for your turf. None of us are sure what the rest of our summer weather is going to bring. I believe luck favors the prepared, preventative fungicide applications are always a better option than curative. They cut the turf disease down significantly and if or when disease does break through, it is much easier to recover from than fighting a disease that is already established during peak summer growing time.

By Dave Gardner, Ph.D.

Turfgrass managers must maintain uniform, dense and aesthetically pleasing turfgrass under various conditions and uses. Often, we must apply preemergence herbicides to control annual weeds, particularly crabgrass. Many factors influence performance of preemergence herbicides including chosen product, soil type, application accuracy, and weather at and after application. A frequent problem is “breakthrough” which occurs when a weed establishes where a preemergence herbicide was applied.

Preemergence herbicides form a barrier at the soil surface that act on germinating weeds and prevent their development. Ideally, after application an herbicide would remain at the soil surface at a concentration necessary to prevent weed germination during the entire window in which weeds germinate before dissipating into harmless materials. There are several processes that affect the fate of pesticides. Above the soil pesticides may degrade by sunlight (photodecomposition) or transported from the target site in flowing surface water (runoff), volatilize to the atmosphere or transported by wind (drift). Pesticides may also leach and potentially contaminate groundwater. But, for preemergence herbicides these processes are mostly unimportant.

In soil preemergence herbicides mostly bind to soil particles and organic matter and then are degraded by soil microbes (Figure 1). Persistence of pesticide varies depending on product applied, temperature and soil moisture at and after application. Longer persistence means it is more likely to prevent annual weed development during the entire period for germination.

You should note excessive rainfall and higher temperatures after application that can result in faster product breakdown, but this is beyond our control. There are things you can do to minimize the chance of breakthroughs of your preemergence herbicide. Choose a long lasting active ingredient such as prodiamine or dithiopyr. Time the application according to growing degree day models or phenological indicators like forsythia bloom but apply as late as possible prior to germination. On sites with severe annual weed pressure, later applications of prodiamine, early to middle April, are more likely to work compared to those applied in March. Dithiopyr also has postemergence activity on 1-2 leaf stage crabgrass thus can be applied as late as mid-May in most years. Apply at the correct application rate and follow the label directions regarding post-application procedures such as watering in.

Regarding application schedules, one school of thought is to apply the product all at once and the other is to apply at half rate twice 6-8 weeks apart. There is no consensus in the research literature as to which works better. I recommend one application as late as possible. But use the scheduling that has worked best for your company in the past.

By Brian Miller

I am a first-year master’s student advised by Dr. Tyler Carr and am researching the effects of autonomous mowing versus conventional rotary mowing on weeds in cool-season lawns. Autonomous mowers have become quite popular in the last 3-5 years due to improvements in their technology, however, the short- and long-term impacts of autonomous mowing on weed dynamics and turfgrass competition are not well understood. To better understand the impacts of autonomous mowing, we designed a project to evaluate the effects on perennial broadleaf weeds (dandelion and white clover) and a separate project to evaluate the effects on summer annual grassy weeds (goosegrass and crabgrass).

This experiment began in spring 2025 and will continue through 2026. The autonomous mower mows every 2 days, and the walk-behind rotary mower is operated according to the one-third rule. Both mowers operated at two different heights of cut, 2-inches and 3.5-inches. Prior to the start of mowing treatments, we hypothesized that through frequent autonomous mowing, turf density would increase, leading to reduced weed populations compared to conventional rotary mowing practices. We also hypothesized that autonomous mowing would suppress seedhead production in summer annual grassy weeds which may reduce the weed seedbank more effectively than conventional rotary mowing.

From late April 2025 until late October 2025, data on a combination of subjective and objective response variables was collected. Visual turf quality, visual turf density, and an estimate of percent weed coverage were assessed every two weeks

Preliminary results from the summer annual grassy weed experiment demonstrate that mowing at 2-inches averaged 3× more crabgrass than mowing at 3.5-inches. Additionally, rotary mown treatments averaged 1.7× more crabgrass than those mowed with an autonomous mower. Additionally, beginning in July, the autonomous mower at 2-inches resulted in greater turfgrass density than the rotary mower at the same height of cut. On average, mowing at 3.5 inches had greater density than mowing at 2-inches.

Our main conclusions from the first year of the experiment were that the higher mowing height decreased crabgrass percentage and rotary mown treatments had increased crabgrass relative to autonomously mown treatments. Also, when mowing at 2-inches, turfgrass density increased when using an autonomous mower compared to a rotary mower. We will be repeating this study in the upcoming growing season.

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By Shaohui Wu, Ph.D.

If you had a crystal ball for 2026, what is your prediction for white grub occurrence and the probability of damage?

It is hard to predict white grub occurrence and potential damage in the next season. Many factors affect grub populations, and climate conditions in summer/fall are ranked top. Most grub species occurring in Ohio have an annual life cycle: eggs in July, three larval instars developing in August-September and then overwintering as 3rd instars until April, pupae in May-June, and adults in June-July. Egg hatching needs sufficient soil moisture, and thus drought in July may reduce egg survival. If drought occurs in August-September, grubs may have delayed development and overwinter as late 2nd instar instead of 3rd instar. Last year, drought occurred in many Ohio counties from August to September. This might have postponed grub development, leading to potential damage this spring, and delaying adult emergence and the next generation occurrence.

There is a belief that drought in the previous year would reduce grub populations in the next season. It is possible but not always. Japanese beetle adults tend to choose lush turf with good soil moisture to lay eggs, while other species less likely do so. Thus, irrigated turf may attract higher grub populations, but non-irrigated areas may still have grubs and drought stress may reduce turfgrass tolerance to grub feeding, deteriorating the damage. Some grubs will survive and produce the next generation.

Scouting and monitoring grub populations are critical to prevent damage, especially at sites with a history of grub damage. Sites receiving preventive treatment are at lower risks but still need attention in case of control failures.

Purpose: A quick, scannable list of timely tasks and reminders for the season.

By Tyler Carr, Ph.D., Dave Gardner, Ph.D., Pam Sherratt, & Shaohui Wu, Ph.D.

• Assess irrigation systems to ensure heads, valves, and controllers are fully operational.
• Mow frequently enough to satisfy the one-third rule and return clippings (when practical) to reduce nitrogen fertilization requirements.
• Repair goal mouths and other heavily trafficked areas weekly, with perennial or transitional ryegrass divot mix or sod + starter fertilizer.
• Apply 0.5 lb N/1000 sq.ft. with a slow-release fertilizer source to maintain growth and promote recovery  going into the stressful summer period.
• Apply prodiamine in mid-April or dithiopyr until mid-May for preemergence crabgrass control.
• Control broadleaf weeds in mid spring with a 3- or 4-way postemergence herbicide.
• Scout in June for control of spring/early summer annual broadleaf weeds and nutsedge.
• White grubs might have delayed development due to drought last fall; watch out potential grub damage this spring if not treated last year.
• Scout annual bluegrass weevil (ABW) populations with soap flushing in low-cut turf in late March-mid April, apply a pyrethroid at peak densities (forsythia half gold: half green) if > 10 weevils/sq.ft.
• Scout ABW larvae with saline extraction in late April-mid May, apply a larvicide (tetraniliprole, cyantraniliprole, novaluron, or isocycloseram) in early (dogwood full bloom) to mid larval stages (hybrid rhododendron full bloom) if more than 30-50 larvae/sq.ft.

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