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Major Pests and Control Programs for the MD Turfgrass Industry in 2023 – Part 1: Sports Turf

A survey was conducted in the fall of 2023 to determine the key turfgrass pests within the turfgrass industry. The survey asked turfgrass professionals within the areas of sports turf, lawn care, sod production, and golf course management what their major pest problems were within the areas of insect, weed, and disease problems and what type of control programs were used. The major pest problems differed for each area of the turfgrass industry and was also related to the turfgrass species and/or cultivar that was being maintained. The graph below illustrates the difference in weed pests between lawn care and sports turf operations. For sports turf the key weed pests were goosegrass followed by crabgrass and annual bluegrass while in lawn turf Japanese stiltgrass was reported as a key weed pest by lawn care operators followed by crabgrass. Rough bluegrass and common bermudagrass were cited but in less frequency.

Figure 1. Differences in key weeds between sports turf versus lawn turf

The concept of key pests, key plants, and key locations is a cornerstone in implementing effective IPM programs for the turfgrass industry. Also, acceptable pest threshold levels varied depending on the type of turf and its intended use. The following article will examine these differences and similarities with regards to pest problems and control programs within the different components of the turfgrass industry. Due to the complexity and length of the article it will be delivered in four installments with the first one covering sports turf.

Sports Turf Management

Survey respondents in this area of the turfgrass industry covered the range of maintenance input levels from professional fields to county recreational fields and also the type of turfgrass that was being maintained. The major turfgrass species found on sports turf was bermudagrass followed by tall fescue and perennial ryegrass. Kentucky bluegrass by itself or seeded within a bermudagrass field made up a minority of sports turf fields

Bermudagrass Fields

Over the past 20 years major improvement in the bermudagrasses with regards to turf density, lower mowing height tolerances, improved color, disease resistance, and winter hardiness has made the bermudagrasses the preferred species to find from county or school recreational fields to the collegiate and professional sports fields in Maryland. The major concern with the bermudagrasses is lack of color during dormancy and the likelihood of winter kill. The principal bermudagrass cultivars listed were ‘Tahoma 31’, Latitude36’, ‘Patriot’, ‘IronCutter’, and common bermudagrass.

Figure 2. The percentage of sports turf managers using bermudagrass cultivars. Often several different cultivars were used on different fields at the same facility.

A number of bermudagrass fields are overseeded with perennial ryegrass to provide color for dormant bermudagrass turf. Color is an important quality factor for sports fields and is often demanded by stakeholder groups.

Figure 3. Bermudagrass overseeded to perennial ryegrass at the UMD practice football fields in October 2021.

Tall Fescue Fields

The tall fescue sports fields are often established at county recreation fields and/or at high school fields that are maintained at higher mowing heights. Treatment thresholds often are on an “as needed” basis except for preemergence crabgrass or goosegrass control.

Figure 4. A tall fescue field at a county park. Summer 2023.

Kentucky Bluegrass Fields

These fields are mainly found on baseball fields at the professional level such as Nationals Park / Oriole Park at Camden Yards or at several college baseball fields. These fields are often mowed at 7/8 to 1 1/4 inch. Due to visual (low pest thresholds) and playability requirements these fields are often treated preventatively for pests.

Figure 5. A Kentucky bluegrass field at the Nationals Park.

Major Pest Problems

Weeds

The major grassy weed pest was goosegrass, followed by crabgrass and annual bluegrass. The control products mentioned most often were Barricade (prodiamine), Dimension (dithiopyr), and Ronstar (oxadiazon). For effective goosegrass control Ronstar was the preferred choice and applied as a preemergence in the spring while Barricade and Dimension were the top two choices for crabgrass control. For bermudagrasses not overseeded with perennial ryegrass in the fall, Barricade was often used to reduce annual bluegrass germination.

Sports fields that consisted of bermudagrass and overseeded to perennial ryegrass in late summer/early fall often were treated to remove perennial ryegrass in the late spring allowing a smoother transition to bermudagrass. The herbicides used were Revolver (foramsulfuron), Tribute Total (foramulsufuron, halosulfuron, and thiencarbazone), and Negate (metsulfuron and rimsulfuron).

The major broadleaf weed found in sports fields was clover with 60% of respondents indicating this weed, followed by nutsedge at 25%. With regards to broadleaf weed control practices a majority of the field managers indicated that they only applied broadleaf herbicides as a spot treatment. Phenoxy based herbicides were the herbicide of choice for clover while halosulfuron containing products such as SedgeHammer and ProSedge were used for nutsedge control.

Approximately 25% of sports turf managers did not apply herbicides or would hand weed if practical.

Cultural and mechanical programs that were mentioned to reduce weed encroachment included aerification programs, fertility programs to enhance turfgrass stand density, hand weeding, fraise mowing, and controlling traffic.

Insects

The major insect pests were white grubs with billbugs and fall armyworm as minor pest problems. Acelepryn (chlorantraniliprole) was used by a majority of the field managers (60%) followed by Dylox (trichlorfon) (30%) and Tetrino (tetraniliprole). Insect control decisions were based on pest history and on a as needed basis. Cultural programs to address insect pest damage were selecting insect resistant cultivars and promoting turfgrass growth to help in recovery of insect damage.

Figure 6. White grubs were listed as the major insect pest problem on sports turf fields.

Diseases

The principal disease pests were based on the type of turfgrass. For bermudagrass fields spring dead spot was the key disease while on tall fescue fields brown patch was the major disease. Summer patch and dollar spot were the key diseases on Kentucky bluegrass fields. Also, the level of maintenance and restrictions on pesticide applications to fields would determine if disease control was applied preventatively, on an as needed basis, or not at all. A majority (60%) of field managers indicated that they applied fungicides on an as needed basis. However, if spring dead spot was present on bermudagrass fields or had a history on specific fields then a majority (80%) of managers would treat for this disease preventatively.

Figure 7. Spring dead spot disease on bermudagrass. Photo taken in early April.

On tall fescue fields brown patch and dollar spot were key diseases followed by red thread and gray leaf spot. On the Kentucky bluegrass fields that were present on professional and collegiate baseball fields and mowed at approximately 1" preventive disease control programs were in place to control key diseases such as summer patch, dollar spot, and brown patch.

Disease control practices encompassed both chemical and cultural programs. The cultural programs mentioned included selecting disease resistance cultivars, irrigation timing to reduce leaf wetness and disease development, and fertility programs that help reduce disease severity by promoting plant growth.

Disease control with fungicides varied with respect to the disease and turfgrass species. For spring dead spot in bermudagrass the preferred fungicide was Kabuto (isofetamid) or Velista (penthiopyrad). For summer patch on low mowed Kentucky bluegrass the strobilurin (Qol) fungicides such as Heritage (azoxystrobin) or Fame (fluoxastrobin) were applied. If sports turf fields had a low pest threshold, then a preventative disease control program was implemented and would often consist of fungicides in the DMI chemistry such as Banner Max (propiconazole), strobilurin chemistry such as Heritage, and the SDHI chemistry such as Emerald (boscalid). The multitarget chlorothalonil fungicide was also added to a spray program.