Turfgrasses have many benefits. In areas where pavement and other impervious surfaces dominate the landscape, a turf can prevent runoff and function as a water purification system. As a recreational surface, turfgrass is cost effective, resilient and capable of minimizing injury.

A significant amount of turfgrass research has concluded that when managed properly, turf fertilizers and synthetic chemical pesticides do not pose a significant threat to water quality or human health. Still, answers to concerns regarding direct human exposure to chemical pesticides, however, remain inconclusive, therefore every effort should be made to minimize the use of pesticides and when using them, apply them correctly. To further understand specific health effects of pesticides used in turf visit http://www.envirocancer.org/turf.

Efforts to reduce chemical use on turf should include an understanding of how turfgrass grows and responds to management. Turf management requires that the professional manager pay particular attention to selecting turfgrass species and using management practices that promote plant health.

Another major consideration is the expectation of turf quality and use. It becomes especially important to be reasonable about visual quality based on how you will use it. For example, it is difficult to maintain high visual quality under intense traffic without significant economic costs.

Environmentally compatible turfgrass management requires consistent and vigilant plant health care. Healthy, vigorous plants grow in fertile, well-drained soils. Therefore, the foundation of plant health care involves good soil management. This is most effectively accomplished during turfgrass establishment and before renovation. It is the first step in an integrated pest management (IPM) approach (as defined in section 3.4).

Maintaining an environmentally compatible turf – assuring that it be more competitive against insect, disease, and weed pests – requires a thorough understanding of the physical and chemical aspects of soil as well as the biology of grass plants and pests. It also requires an understanding of the dynamic relationship between an organism and it environment. Turf’s essential “organism” is the grass plant. Its environment includes the soil, light, temperature, available water, associated flora and fauna, and humans. Turf management practices affect both the grass plant and its environment. For instance, mowing a turf below its adapted height weakens the plant and increases the amount of light contacting the soil. This causes the soil temperature to rise and can promote weed growth.

3.2 Selecting Turfgrasses

Grasses differ in their ability to adapt to soil and air temperatures, soil fertility, moisture and pH as well as to mowing, traffic and pests. When selecting a grass, refer to http://www.ntep.org for site-specific data on the major cool season turfgrasses. Selecting a well adapted species is the first step in reducing overall reliance on chemical pesticides.

Visually, grasses differ in leaf width (texture), growth habit (bunch-type, rhizomatous, stoloniferous), density and color. This variability exists between and within each species, which partially explains the large number of varieties available for each species.

Important cool-season turfgrass species include Kentucky bluegrass, creeping bentgrass, perennial ryegrass, tall fescue and the fine-leaf fescues. Kentucky bluegrass (Poa pratensis) is the predominant high-quality turfgrass in northern climates for lawns and sports turf. It is a well-adapted perennial species that produces rhizomes (underground lateral stems), which enhance the species’ ability to form a thick mat or sod.

Kentucky bluegrass grows most successfully in well-drained sites receiving full sun and regular fertilization. However, 45 to 90 days are required to establish a dense turf from seed, therefore many Kentucky bluegrass areas are established from sod. Improved aggressive compact or Midnight-type varieties require supplemental irrigation to avoid the summer dormancy associated with warm, dry conditions. Older common varieties such as Bartitia and Kenblue, however, have been successful with no irrigation in northern climates.

The major pest problems of Kentucky bluegrass include fungal diseases such as leafspot, dollar spot and necrotic ringspot as well as root-feeding insects such as white grubs and surface feeders such as billbugs.

Perennial ryegrass (Lolium perrenne) is a bunch-type grass lacking the lateral growth of rhizomes and stolons. Rather, each plant gets thicker at the base with side shoots called tillers. This makes ryegrass reliant on overseeding in high traffic situations such as sports fields. Ryegrass germinates from seed in two to four days and provides a uniform turf within two weeks. It is most successful when it receives regular care in sites that are fertile, well-drained and in full-sun.

The major pest problems of perennial ryegrass include fungal diseases such as red thread, rust, brown patch, and Pythium blight. Gray leafspot has become a damaging disease of perennial ryegrass, breeders have developed a few resistant varieities such as Paragon GLR. Additionally, many ryegrass varieties contain endophytic fungi. Referred to as endophytes, the fungi live in association with the grass plant in the leaf sheath. Endophytes produce natural chemicals that deter surface-feeding insects such as chinch bugs and sod webworms, but have no effect on white grubs or other root feeders.

The fine-leaf fescues include strong or slender creeping red fescue (Festuca rubra), chewings fescue (Festuca rubra var. commutata), hard fescue (Festuca longifolia), and sheep fescue (Festuca ovina). The fine-leaf fescues are characterized by a medium to dark green color, narrow needle-like leaves and primary bunch-type, non-spreading growth (except for creeping red fescue, which can produce a mat from its rhizomes). They are exceptionally slow growing, requiring little to no supplemental fertilizer and are particularly tolerant of shade.

The fine-leaf fescues are well adapted to infertile, acidic soils and, compared to other cool-season grasses, are most tolerant of shaded conditions. As a group, the fine fescues are not tolerant of traffic and, similar to ryegrass, these bunch-type grasses do not fill in open spaces. The fine fescues are the greatest thatch producing cool season turf. To minimize this problem limit N fertility.

The fine fescues have few major pest problems except during persistent wet conditions when red thread and leaf spot can be severe. Similar to the ryegrasses, certain fescue varieties have endophytes that repel surface-feeding insects such as chinch bugs and sod webworms, but they are susceptible to infestations of white grubs, which feed on the roots.

Tall fescue (Festuca arundiacea) is a bunch-type grass with substantially wider leaves than fine-leaf fescues. It is an exceptionally deep-rooted grass, a trait that allows it to persist under drought conditions. It is tolerant of wear. To be successful in a heavily turf that creates voids, it requires regular seeding due to its bunch-type growth. Since it is less winter hardy in the seedling stage, tall fescue should be sown in the late spring (May/June) or late summer (August).

Tall fescue is susceptible to brown patch and Pythium and may suffer from rust infestations. Proper nitrogen fertilization is vital to avoid and minimize these pest problems.

Bentgrass species include creeping (Agrostis palustris), colonial (Agrostis tenuis) and velvet (Agrostis canina). They are primarily used for golf, tennis and lawn bowling turf. Bentgrasses spread by aboveground stems known as stolons and are most successful mowed less than 0.75” with reel-type mowers

The bentgrasses are adapted to acidic, infertile soil. However, they can adapt to pH levels in excess of 8.0 The most common creeping bentgrass variety is Penncross however new varieties such as L-93 have increased shoot density that allows for mowing below 0.125” and have improved disease resistance, especially for dollar spot. Dollar spot resistant varieties include L-93, LS-44, and Declaration.

The most common disease of creeping bentgrass is dollar spot and insect problem is cutworm. In general, creeping bentgrass is managed in a mixed stand with annual bluegrass that reduces turf quality and increases fertilizer and pesticide use. Annual bluegrass (Poa annua and Poa annua reptans) is very susceptible to a variety of diseases and insects.

Annual bluegrass, an invasive winter annual weed, successfully adapts to intensely managed turf and following initial invasion of the true winter annual type, has the capacity to become more perennial. Perennial forms are dense and produce significantly less seedheads.

Annual bluegrass is the primary turfgrass species on most northern golf courses. It is plagued with environmental and pest stress, most notably winter injury, summer decline and a myriad of fungal pathogens such as anthracnose basal rot and dollar spot.

3.3 Cultural Practices

3.3.1 Mowing

Mowing is probably the most poorly understood of all cultural maintenance practices. Simply, lowering the height of the cut below the acceptable range for each turfgrass species and root growth declines, thereby reducing the plant’s ability to extract water and nutrients from the soil. Furthermore, close mowing increases the level of maintenance required for acceptable quality.

Turf should be mowed so that no more than one-third of the leaf tissue is removed with each mowing. For example, a lawn that is maintained at 3 inches should be mowed when it reaches 4.5 inches. Grass clippings contribute nutrients to the soil when they are returned. They should be left on the turf as long as there are no clumps to smother the grass below.

When mowing height is increased, the canopy shades the soil and the soil surface gets cooler. In fact, studies show fewer weeds(broadleaf and grassy) as a result of mowing heights at the higher end of the species range. In addition, when taller blades of grass shade and cool the soil, seeds of warm-season grassy weeds such as crabgrass (Digitaria spp.) are less likely to germinate.

3.3.2 Fertilizing

Proper nutrition is as vital for plant health as a balanced diet is for human health. A person who eats more of the wrong foods and not enough of the right foods has a greater chance of experiencing poor health, especially when he or she is also under stress or exposed to germs. To maintain a healthy turf, a proper amount of nutrients must be available. Fertilizers help supply nutrients to the turf necessary to maximize plant health.

In general, soil testing can serve as the basis for fertilizing, however there is concern recently that current soil testing methodology overestimates turf nutrient needs. Still, if a soil test indicates adequate nutrients in the soil, fertilizing provides no benefit and can be, in the case of phosphorus, potentially detrimental to the environment. If fertilizer lands on paved surfaces or is applied and not watered in properly, it can be washed into storm drains and contaminate any body of water where the storm drain discharges.

Nitrogen is the primary nutrient for the growth of healthy turf. It is important to several physiological aspects of plant growth, especially shoot and root growth. However, improper timing of nitrogen applications can result in excessive shoot growth at the expense of root growth – a typical result of early spring applications of water-soluble nitrogen fertilizers.

Research has shown that high rate spring applications of nitrogen do not enhance green up as well as fall applications. In addition, when the soil warms (the actual cause of spring turf green up) and water-soluble nitrogen becomes quickly available to the grass, plants produce shoot growth at the expense of root growth. Thus, over -fertilized primarily spring-fed plants are more stressed going into hot, dry summers because their roots have grown less.

On some occasions spring fertilization is necessary to promote increased turf density after winter’s ice and snow destroy some of the grass plants. Spring fertilization also will benefit turf areas that have not been fertilized in late fall. Turf can successfully compete for space before summer weeds emerge if fertilizer increases turf density. Ideal spring fertilization rates would be at half to one quarter full application rates or 0.25 to 0.5 pounds of actual nitrogen per 1000 square feet.

The most important fertilization for lawn turf grown on a loamy soil is around the Labor Day holiday in early September. High quality golf and sports turf that receives regular light fertilizer applications during the season can maintain that approach until top growth ceases. Historically, we have recommended late season high nitrogen applications of fertilizer, however due to water quality concerns from these late season applications research indicates no more than 0.25 to 0.5 lb of N per 1000 square feet should be applied, especially in southern NY locations where soil freezing is not assured. Fertilization in non-frozen soil areas should cease by mid-October. In addition, there is no evidence that high rates of potassium enhance winter hardiness and may in fact increase disease incidence and severity.

Turf grown on sandy soils should use a high percentage of slow-release nitrogen to minimize leaching past the root zone. Research has demonstrated that on most soils with some silt and clay, it is extremely rare for nitrogen to leach. However, as turf ages organic or labile N accumulates and will contribute to the plant N needs. Therefore, N fertilization programs should also be adjusted based on the age of the lawn.

3.3.3 Irrigation

Turf in northern climates typically requires supplemental irrigation for a few months in the summer. It is possible to maintain a healthy turf without supplemental watering, but it will not be high quality turf for the entire season.

Proper irrigation is critical for maintaining plant health during stressful periods. The most important guideline is to apply what the plant and soil have lost to evapotranspiration, approximately one inch of water per week in the absence of rainfall. To avoid runoff, water should be applied at the rate the water will penetrate in the soil.

The best time to apply supplemental watering is early in the morning. At this time evaporation rates are low, which improves efficiency, and the grass dries more quickly. It is also important to minimize the length of time grass blades are wet to reduce the occurrence of fungal diseases.

It is normal for cool-season grasses to go into summer dormancy, brought on by low rainfall. Studies have shown that as little as one-tenth of one inch of water over a three-week period is all that is required to keep them alive. Either too much or too little water can weaken the plants, making them more susceptible to pest problems and less likely to recover when cool, moist conditions return.

3.3.4 Problem Solving

Solving turf problems begins with a thorough understanding of the turfgrass plants and their environment. These may result from poor growing conditions or excessive use, which then leads to reduced turf health. The first step in problem solving is to determine the poor growing condition causing the weak turfgrass.

1. Is it low light?

2. Is it poor drainage?

3. Is it compacted soil?

4. Is there still a problem after an unfavorable condition was remedied?

The most common cause of poor turf is poor growing conditions. Maintaining adequate light levels of at least four hours of direct sunlight per day is a good start. Next, assure adequate surface and if needed subsurface drainage. Chronically wet rootzones will increase compaction thereby weakening the root system and compromising plant health.

3.3.5 Weeds

A significant weed infestation can detract from turfgrass visual quality, but often poses no functional or environmental problem. Weeds are best kept under control through prevention. A chronic weed infestation is often the result of turf management practices that reduce the ability of grass plants to grow competitively, and resist insect and disease pests. Optimizing soil fertility results in a denser, more competitive turf. The most effective management strategy with respect to weeds is multi-faceted:

· Understand weed biology and identify problem weeds.

· Carefully evaluate site conditions to determine if they are conducive to optimal turf growth.

· Focus on maintaining a dense, healthy turf.

3.3.6 Diseases

Fungi cause most turf diseases. The fungal pathogens that infect grasses live mostly as saprophytes, feeding on dead or decaying organic matter, until environmental conditions favor infection.

Most turf disease occurs when the grass plants are environmentally stressed and are in a weakened condition which could favor pathogen growth.

Many products such as microbial inoculants, composts, and other bio-stimulant products claim to prevent or control diseases. While some research indicates that composts and inoculants can suppress certain diseases, the majority of products have not been tested under controlled conditions. Nevertheless, it might be worth testing the performance of a small amount of material on a limited area of your turf. Overall, however, a healthy turf, planted with a disease-resistant variety, is the best defense against turfgrass diseases.

3.3.7 Insects

Insects are abundant in nature and make up a substantial portion of all the forms of life on this planet. In fact, the turf environment sustains high populations of insects. Very few are damaging.

Grass plants can tolerate substantial insect feeding. The principles of an IPM program are based on the principle of insect population threshold. Simply the threshold is the number of insects per unit area, beyond which the grass is significantly injured. In early spring, for example, an actively growing turf can tolerate feeding by 10 to 15 white grubs per square foot of turf. In late August through October, larvae (or grubs) of the Japanese beetle surface to feed on grass roots and should be monitored to determine if control is necessary.

Damage by surface-feeding insects occurs from June through August. One way to inspect for these insects is to apply a solution of soapy water to a small area at the periphery of the damaged turf; the insects will come to the surface within a few minutes.

Perennial ryegrass, fine-leaf and tall fescues enhanced with endophytes have been shown to be resistant to surface-feeding insects. One good result of the association between the endophytes and the grass plant is that a natural chemical is produced, which is present in the leaf sheath and deters insect feeding. If a stand is lost to a surface-feeding insect, every attempt should be made to introduce an endophyte-enhanced variety to prevent future damage. Studies have shown that as little as 20 percent endophyte enhanced grasses in a stand will significantly reduce damage to turfgrass areas.

3.3.8 Summary

Environmentally compatible turfgrass management programs use natural resources (i.e. water, fertilizer) efficiently to preserve the quality of the immediate and nearby environment. All parts of turf management are intimately linked. Altering one component ultimately influences the performance of another.

· First, be sure to understand the physical and chemical aspects of turf soil.

· Next, select grass plants that are adapted to the region and can meet your expectations for quality and use.

· Next, maintain plant health through timely and proper cultural practices.

· Finally, manage weeds, diseases and insect pests, while minimizing the impact of your methods on the environment.

The result will be a healthy turf that looks good, performs well and benefits the environment.

3.4 Integrated Pest Management

Cornell’s Pest Management Guidelines for Commercial Turfgrass provide turfgrass managers with information on the legal and appropriate use of pest management practices and products. The focus is primarily on pesticide options, the legality and availability of which change frequently. However, these guidelines should only be used in the context of a complete, site-specific, integrated pest management (IPM) program. Such a program cannot be detailed within the confines of this book, but an introductory IPM discussion is presented below. In addition, the online version of these guidelines at http://IPMguidelines.org offers more IPM information by linking to resources such as turfgrass cultural practices, species and cultivar selection, diagnostics, and biological pest management. The printed version is a handy, quick, field reference for managers, but readers are encouraged to also explore the additional resources presented online.

IPM is a decision-making process that strives to make best use of all available management tools, including cultural, biological, mechanical, environmental, and chemical methods. IPM is effective, economical, and minimizes risk to the environment and human health. IPM is also known as integrated turfgrass management, best management practices or plain old common sense. IPM is also the basis of a good organic program, even though synthetic chemical pesticides are not included in those programs.

Definitions of IPM are numerous, but most agree on the following goals.

Minimize: Losses to pests; costs; negative effects on human health and the environment; and pesticide resistance potential.

Maximize: Cultural, mechanical and biological pest controls; effectiveness of chemical pesticides (when they must be used); turfgrass quality; and populations of beneficial organisms.

Any decisions based on these criteria involve balance and potentially compromise, and depend on factors such as pest pressure, weather, quality demands and intended use of the area. Therefore, turfgrass managers select distinct IPM practices in various settings and circumstances. As practitioners, you know that IPM is diverse and cannot be applied according to "cookbook" recipes—it is a customized, proactive approach. The practice of IPM can be described in seven steps.

3.4.1 Plan

Successful businesses set goals and plan ahead. Likewise, good IPM requires good planning. Start with the big picture, such as “improve the environment with a quality turfgrass product”, and then work into finer details. Ask how you can improve the environment on your golf course or your customers’ properties, in the watershed, and in the community. Determine the current condition of the property. What grass and weed species are present? What are the soil conditions? What other pest problems are possible, and which are likely to occur? Consider the history from that property as well as from the local area.

A complete plan includes each of the six steps described below, and following it may require training a staff person on how to monitor and identify pests, attending educational sessions, or producing informative literature for customers. Plans should be flexible enough to incorporate new information and have contingencies for unexpected situations, such as invasion of a new or rare pest.

3.4.2 Monitor

Turfgrass areas should be monitored on a regular basis to assess health of the turfgrass planting, as well as signs and symptoms of pests, and other stress factors such as drought and nutritional deficiency. Proper identification of pests (including weeds, insects, diseases and vertebrates) and underlying cultural problems is essential. Know how to identify each pest species, the season when they occur, the conditions that favor them, and how they can be detected. Awareness of potential and probable pest problems is key to being able to prevent and monitor for them.

Pests must also be quantified to determine if populations are rising or declining, if thresholds have been reached, and whether previous control measures were successful. The pest stage (e.g. weed seedling, insect pupa) is also important for determining if and when intervention may be appropriate. Lawn care professionals can enhance their monitoring efforts by using lawns with known histories of problems as early indicators in individual neighborhoods. Likewise, managers of golf courses, institutional grounds and sod farms can follow specific indicator areas within the larger property.

Armed with knowledge of both pests and site, you should monitor or “scout” turfgrass areas on a regular basis. For low maintenance areas, that can be weekly or monthly, depending on the current pest pressure, pest biology, time of year, and expected use of the area. Higher maintenance areas need a minimum of weekly monitoring, with putting greens requiring daily examination. Disease and insect problems can appear relatively quickly and frequent monitoring can provide an early warning of problems when conditions are conducive for that pest, especially in areas with a history of the problem. Weeds, on the other hand, invade and grow more slowly and can be monitored as infrequently as three times a year.

3.4.3 Manage

Sound horticultural practices are fundamental to growing and maintaining healthy turfgrass, and healthy grass is more resilient to pests. Maintain the turfgrass areas with the best cultural management strategies that are feasible for the site, including optimal grass species and variety selection, watering and mowing practices, and fertility inputs based on soil or tissue testing. Minimizing turfgrass stress, selecting pest-resistant grasses and proper maintenance of equipment have the greatest impact on reducing pest problems.

3.4.4 Analyze

IPM is a knowledge-based decision-making process, and the use of action or treatment thresholds is one of its hallmarks. Thresholds are flexible guidelines, usually defined in terms of the level of pest abundance or damage that can be tolerated before taking action, and are based on numerous aspects of the biology of both pest and plant. IPM managers apply thresholds to plan short and long term pest management actions and strategies for each turfgrass area, after considering monitoring data, current and predicted weather conditions, turf value and customer expectations. This analysis is an ongoing process that allows managers to make timely and appropriate decisions for individual areas throughout each growing season. The determination that a pest problem warrants intervention, such as the use of a pesticide, is part of a thorough analytical process.

3.4.5 Intervene

At times the monitoring and critical analysis process will reveal a problem that needs remediation. At this point, the professional intervenes with a cultural, physical, biological, or chemical control tactic. The cultural practices discussed elsewhere in these guidelines are mainly preventive, but can sometimes be used to minimize the effects of a pest outbreak. Midnight mowing is an example of a physical tactic that has effectively reduced cutworm populations on putting greens, and may also be useful on higher cut turf. Biological controls have received a great deal of attention in the past 20 years, partly due to the decline in chemical options. Several products are now available and legally registered as pest control products, and are listed in the appropriate pest tables. Remember that biologicals tend to be more pest and climate specific than traditional chemical pesticides, and therefore must be appraised on a case-by-case basis. Examples include Trichoderma harzianum and Bacillus licheniformis for disease management, and entomopathogenic nematodes and Bacillus thuringiensis for insect control.

Application of chemical pesticides, a common intervention for many managers, is the last option for an IPM practitioner. Close attention to the monitoring and analysis of individual areas often allows for spot treatments rather than whole area treatments and the use of lower toxicity treatments, before pests reach high levels. An IPM practitioner will consider all approaches and select the least disruptive option that will be effective.

3.4.6 Keep Records

Many benefits of IPM are lost if information is not recorded. All considerations from the analysis process should be documented, as well as the cultural practices and intervention tactics employed. Professionals should keep good records of cultural practices; turfgrass health; pest incidence, identity, and severity; and all intervention tactics, especially the use of pesticides. These records are critical for in-season decision-making as well as historical documentation of pest problems and efficacy of actions taken. From this base, personalized thresholds can be developed and the effectiveness of treatment decisions evaluated. Whether you spent $500 or $50,000 on pest control last year, you should know if it was worthwhile and necessary.

3.4.7 Communicate

Good communication with staff, customers, and community members is an essential aspect of IPM. Regardless of who is designated to monitor, all staff should be aware of pest problems and management activities. All employees should be encouraged to report potential problems, and IPM training should be provided to as many staff as possible. The IPM approach also needs to be conveyed to customers, whether they are homeowners, golfers, or neighbors. The turfgrass professional should articulate to customers how his/her expertise along with information gleaned from monitoring and a scientific knowledge base combine to create a customized, site-specific IPM program. Describe IPM in promotional literature and on your website. IPM efforts pay off many times over when communicated among staff, to customers, and the community.

Pest Management Guidelines A Cornell Cooperative Extension Publication	Cornell Guide for Pest Management of Turfgrass
Home \| CALS \| PMEP \| All IPM Guidelines