Editor’s note: This article was originally published in the June 2010 issue of SportsField Management.
You probably know the components of Integrated Pest Management (IPM): right plant, right place; disease-resistant cultivars; use of biological agents, such as endophytes; soil modifications to promote root health; appropriate timing of irrigation; establishment of a pest threshold; aerification to relieve soil compaction; fertilization according to the needs of the plant; and so on.
Another crucial part of the IPM strategy is the understanding and utilization of treatment windows, which is the period of time when a pest is most vulnerable. The application of treatments during this time is more effective than any other, usually requiring less pesticide, fewer applications and higher pest control.
How to time
To begin using timing to your advantage, the first step is to document past pest history. During the season, keep a record book or turf diary, which will assist you with keeping track of what caused damage and when. A turf diary does not need to be complicated. It can be as simple as a spiral-bound notebook with listings of dates, pests observed, numbers of pests or extent of injury observed and control methods utilized.
Next, to increase the effectiveness of your treatment window efforts, investigate the best time to treat each pest that has caused turf damage at your facility. This can be done in several ways. One is to attend workshops conducted by professional organizations, and another is to consult with sports facility managers nearby. University researchers and local extension professionals may also be available for consultation.
General guidelines for common pests
It’s difficult to be specific for locations and target pest in every part of the U.S., but here are some general guidelines for common pests of sports turf.
Pest and treatment window guidelines
- Annual grasses (crabgrass, goosegrass, foxtail): These grasses begin germination when the soil temperature warms to 55 to 60 degrees and stays there for three consecutive days. Preemergence herbicides should be applied after this has occurred.
- Perennial grasses (tall fescue, smooth bromegrass, quackgrass): These grasses live from year to year. Much like perennial broadleaf weeds, mid to late fall offers the best treatment window, or early spring as they are beginning to make new growth.
- Broadleaf weeds (plantain, dandelion, clover): Mid to late fall is the best time to control broadleaf weeds as cuticle thickness is less than at other times and active translocation is occurring in the plant.
- White grubs (masked chafers, black turfgrass ataenius, May/June beetles, Japanese beetles): The second stage of their life cycle, the early larval stage is the most vulnerable. For most grubs, this is late summer or early fall.
- Sod webworms: Webworms have two to three generations per year, depending on locale. Early larval stages are most easily controlled. Inspect for webworms beginning in early summer and carrying forward until midfall in most seasons.
- Bluegrass billbugs: Billbugs can be controlled in the adult stage in midspring with contact insecticides, or through preventative treatments made in early spring.
- Dollar Spot: Dollar spot is best treated in late spring or early summer at the onset of classic symptoms.
- Leaf spot/melting out: In areas with a history of leaf spot, treatments should be applied just prior to historical infection periods. Early spring is the classical time for infection.
- Pythium Blight: In areas with a history of Pythium blight, treatments should be applied just prior to historical infection periods. Early to midsummer is the classic time for infection.
- Summer patch/necrotic ring spot: A lag time between infection and the onset of symptoms exists for this disease. Infection occurs in midspring, but turf damage shows up midsummer. Treatment in early to midspring is crucial for control.
- Brown patch: In areas with a history of brown patch, treatments should be applied just prior to historical infection periods. Midsummer is the classic time for infection.
- Stem rust: Late summer and early fall is the customary treatment window for stem rust.
Play will dictate timing
Weather conditions and pest biology are primary treatment window factors, but team play is another important consideration. This is especially true during the season of competitive play. For example, during football season, the game field is likely to be in use, as well as out of play, for consecutive weeks. If the team leaves town or plays at another field in town, an opportunity is created for extensive field work. During away games, two weeks are available to treat, overseed, aerify, etc. Likewise, opportunities for IPM strategy implementation are limited during back-to-back home and home game sequences.
Season can dictate timing
Depending on the sport and intensity of practice activities, during off-seasons, turf is under less stress from compaction and wear, resulting in healthier turf than during active play. Often, the result is a lessening need for treatments due to lesser stress, deeper roots and more turfgrass cover.
Inspect and evaluate
The sports turf surface can be confined to only game play, game play and practice, band proactive, varsity and JV teams, multiple sports and every possible combination, making use of the optimal target window for treatment difficult or near impossible. Using the optimal treatment window will positively affect economical, environmental and labor efficiency. If scheduling and use make optimal target windows unattainable, then field quality and playability expectations will also be negatively affected.
John Fech is an extension educator specializing in turf and ornamentals at the University of Nebraska-Lincoln. Roch Gaussoin is a professor of horticulture and extension turf specialist at the University of Nebraska-Lincoln.