9 Integrated Pest Management
Integrated pest management (IPM) has been described as follows:
“IPM is a balanced, tactical approach to pest control. It involves taking action to anticipate pest outbreaks and to prevent potential damage. IPM is a pest management strategy that utilizes a wide range of pest control methods or tactics. The goal of this strategy is to prevent pests from reaching economically or aesthetically damaging levels with the least risk to the environment. Such pest management programs—based on the identification of pests, accurate measurement of pest populations, assessment of damage levels, and knowledge of available pest management strategies or tactics—enable the specialist to make intelligent decisions about control. IPM offers the possibility of improving the effectiveness of pest control programs while reducing some of the negative effects.”
Many people are under the false assumption that IPM represents a non-chemical approach to pest management. In fact, IPM programs use both non-chemical and chemically based methods of pest control. In the long run, this integrated approach is more effective and can be less expensive than traditional pest management approaches that rely only on the use of chemicals. Dealing with pests through an IPM program requires a basic understanding of pest biology and behavior to select effective methods of control. When chemical control is warranted, pesticides should be selected and applied to not only meet regulatory requirements, but also to avoid impacts to non-target species (such as pollinators) and to avoid pesticide runoff or leaching.
9.1 Regulatory Considerations
Federal and state regulations cover practically anyone who manufactures, formulates, markets, stores, handles, or uses pesticides. Pesticides should be used and managed in keeping with regulatory requirements and best practices, as discussed in the “Pesticide Management” and “Maintenance Operations” sections.
9.2 IPM Overview
IPM is comprised of a range of pest control methods or tactics designed to prevent pests from reaching economically or aesthetically damaging levels with the least risk to the environment. IPM programs have basic components that provide the opportunity to make informed decisions on the control of pests on the golf course. The steps of an effective IPM program are as follows:
- Identify pests and understand their biology.
- Monitor the pests to be managed.
- Develop the pest management goal by setting pest population thresholds.
- Implement the IPM program.
- Record and evaluate the results.
IPM also encompasses the prevention of pest problems before they occur by selecting cultivars for improved pest resistance, using cultural practices to lessen the potential for pest pressure, and improving the effectiveness of pest control programs while reducing some of the negative effects. Chemical controls can be used when needed but should be selected to have minimal effect on beneficial organisms and on the environment and to minimize the development of pesticide resistance. For more information related to selecting appropriate turfgrass cultivars for Delaware and implementing an IPM for turf, see the “Cultural Practices” chapter and the following additional resources:
- Recommended Turfgrass Cultivars for Certified Sod Production and Seed Mixtures in Maryland. 2016. University of Maryland.
- IPM Series: Turf. 2012. University of Maryland Extension.
- Delaware Pesticide Applicator Guide, Delaware Department of Agriculture.
9.2.1 Identifying Pests
A number of key pests can impact turfgrass in Delaware. Being able to identify these key pests and understanding their biology is important to effectively preventing or controlling outbreaks. Once detected, documentation should include mapping on an area map and recording the date of the outbreak. Though pest pressure will often exist when conditions are favorable, the severity is often greatly reduced by using cultural, biological, and genetic management. As a rule, healthy, well-managed turf better withstands pest outbreaks and recovers more rapidly than unhealthy turf. See Diseases of Turfgrass: Identification and Management (University of Delaware) as a reference to turf diseases in Delaware.
Monitoring through scouting or trapping, as well as identifying alternative hosts and overwintering sites for key pests, is a critical element of a successful IPM program. Monitoring will document the presence and development of pests, as well as the conditions that are conducive for pest outbreak throughout the year. It is essential to record the results of monitoring in order to develop historical information, document patterns of pest activity, and track successes and failures.
9.2.3 Pest Thresholds
IPM is commonly used in agricultural crop production, where economic thresholds for key pests have been established. Pest levels exceeding the threshold levels may warrant treatment. Using IPM is more challenging on golf courses than in an agricultural setting, as agricultural thresholds are based on crop yield whereas golf course thresholds are qualitative, involving turfgrass density and playability. Increased education of golfers and maintenance personnel can increase tolerance of minor aesthetic damage without compromising plant health, play, and overall aesthetics. These thresholds can be determined scientifically or based on site-specific experience.
9.3 IPM Implementation
Management practices in each pest category can be utilized to prevent or reduce the amount of pest pressure on turfgrass. Biological controls or chemical controls may be required once pest thresholds are exceeded.
In the presence of a susceptible host and a conducive environment, plant pathogens can disrupt play by damaging and destroying intensely managed turf. While no measure can completely eliminate the threat of turfgrass disease, turfgrass managers have multiple tactics and tools that can reduce the likelihood of disease. The most common factors that promote turf diseases include close and frequent mowing, poor drainage, excessive thatch, light and frequent irrigation, inadequate or excessive N fertilization, shade, and traffic. For example, summer patch can occur when turf is mowed too closely, given light and frequent irrigations, and fertilized with excessive amounts of N. The use of BMPs for cultural practices promotes healthy, well-managed turfgrass that is less likely to develop disease problems (Figure 19). Disease outbreaks that do occur are less likely to be severe on healthy turf because it has better recuperative potential than stressed, unhealthy turf.
Common turf diseases in Delaware, symptoms and management options are provided in Table 11. See Diseases of Turfgrass: Identification and Management for specific turf disease information for Delaware. Additional references for turf diseases prevalent in the Mid-Atlantic Region and control methods include:
- Maryland Turfgrass Disease Control Recommendations. 2010. University of Maryland.
- Red Thread and Pink Patch Diseases of Turfgrasses. 2007. University of Maryland.
- Identification and Management of Brown Patch. 2011. University of Maryland.
- Dollar Spot Disease of Turfgrasses. 2003. University of Maryland.
- Summer Patch Disease of Lawn Grasses. 2003. University of Maryland.
Table 11. Common turf diseases, symptoms, and management in Delaware.
|Pink Snow Mold|
|Very early spring or late winter; can also occur in late fall||Patches of matted leaves that have a pinkish or red-brown color. Patches may be several inches in diameter and center of may be bleached white. Occurs often in areas under snow cover but can also occur during cool periods with high moisture. All turfgrasses are hosts but are not generally killed.||Avoid high nitrogen and remove thatch. Mow late into the fall.|
|Primarily in the spring and fall; also during rainy periods in the summer||Irregular blighted patches sometimes with a pink cast. Blades are often water-soaked and covered with the diagnostic pink gelatinous fungal growth. Dead blades in affected areas are straw brown, tan, or slightly pinkish. Dark pink/coral antler like strands of mycelium or lighter colored tufts can be seen extending from the tips of dried infected grass blades. All turfgrasses are hosts especially perennial ryegrass and fine fescues. Affects only the blades does not kill turf.||Maintain adequate nitrogen, remove excess thatch, and reduce stress.|
|Leaf spot and melting-out|
|Leaf spot diseases occur in spring, summer, and fall. Melting-out occurs primarily late spring.||Leaf spots can be brown to purple brown, oval-shaped or elongated, with tan centers. Melting out is more severe and results in dieback of roots and crown and thin turf. Found primarily on Kentucky bluegrass, but all turfgrasses can be infected. Bluegrass can be killed by the root and crown phase (melting-out).||Over-seed bluegrass lawns with a resistant cultivar and avoid high nitrogen.|
|Cool weather in spring and fall.||Rings of dead turf several inches to over a foot in diameter with green turf or weeds in the center. Blades appear yellow to brown; roots and crowns will be decayed. Bluegrass and fine fescues are affected.||Over-seed or replace with tall fescue or ryegrass that are resistant.|
|Usually late spring through fall.||Leaf spots are hour-glass-shaped, extend across the blade with bleached centers and brown, purple, or black borders. Early in the morning, cottony fungal growth can be seen on infected blades. Bluegrass, ryegrass, and fine fescues are hosts, especially in poorly nourished turfs. Plants are rarely killed, primarily a leaf blight.||Avoid nitrogen deficits, mowing too low, thatch, leaf wetness, and drought stress.|
|Usually late spring to fall.||These molds produce a gray or black crusty material on blades of turf. It can be rubbed off easily and appears after a prolonged rainy period. This moldy residue may form on plants in rings or arc patterns. These slime molds are not parasitic and do not harm the plants.||Spore masses can be removed by mowing, raking, or washing with a hose. Control thatch.|
|Summer when night temperatures are above 68 degrees F, with high day temperatures and high relative humidity.||Causes a leaf spotting that results in circular brown patches 6 inches to 2 feet and thinned turf. Leaf spots are often irregular and have a thin reddish-brown border. Small patches can coalesce to blight large areas quickly when weather conditions for the disease are ideal. All turfgrass are affected, especially tall fescue and ryegrass. Mature turf is rarely killed. One-year-old stands of tall fescue under severe conditions can be killed.||Avoid high nitrogen in spring, leaf wetness, and excessive thatch.|
|Summer, especially during periods of high temperatures and drought.||Diseased areas are first light green then fade rapidly to a straw color (may be confused with wilting). These areas are often circular or sometimes irregular patches often with living grass or weeds in the center. Sometimes smaller patches can merge and blight large areas of turf. Patches can be sunken and leaves at the borders may have a bronzed appearance. Tip dieback of leaves gives the turf a straw-brown color. Bluegrass and fine fescues older than two years are killed by this disease.||Avoid high nitrogen, wet soil, compaction and low mowing.|
|Late spring to fall||The spore masses can be removed by mowing, raking, or washing with a hose.||Control thatch.|
|Summer; favors hot, humid periods and poorly drained soils.||Circular small spots are matted, grayish, or water-soaked. Patches will follow surface water flow patterns. Infected blades collapse rapidly, are greasy-looking, and wilt rapidly. Fungal growth can be seen in early morning. Plants will often die in 24 hours. Dead plants are often red-brown to brown in color and matted together. Seeding in the late summer can fail due to Pythium damping-off and blight when overwatered. Bluegrass, fescues, and especially perennial ryegrass are killed by this disease.||Avoid high nitrogen, leaf wetness and thatch. Improve drainage.|
|Later summer to fall, especially in shady areas.||The leaves of infected pants have a white to gray powdery growth that gives the leaves the appearance of having been dusted with flour or lime. Infected blades may yellow, wither, and die. All turfgrasses can be infected, especially in shady conditions, blights only the leaves.||Avoid high nitrogen, low mowing, increase light levels, or plant shade-tolerant grasses.|
|Fall||Rust-infected turf becomes reddish-brown or yellow. Rust begins as yellow-orange flecks on individual grass blades and develops into orange or brick-red pustules. Spores within the powdery pustule easily rub off when touched. A heavy rusting can cause leaf blades to die and thin stands of susceptible turf. Primarily perennial ryegrass and bluegrass are infected; most turf including zoysia can be infected. Turf can be thinned but rarely is killed.||Avoid low nitrogen and leaf wetness. Plant resistant cultivars.|
|Any time of year.||Rings or arcs of dead grass bordered by inner and outer zones of dark green grass, or rings of very green grass without a dead zone. Rings can be from 1 to 4 feet in diameter or range up to 20 feet. Mushrooms may or not be present in rings. All turfgrass can be affected, especially at dry locations and poorly nourished turf.||Avoid thatch, buried organic debris, and drought stress. Fertilize and rake mushrooms to mask symptoms. Core aeration of stimulated and dead zone, and drenching with an organosilicone wetting agent may alleviate symptoms. Eventually the symptoms will disappear|
Crabgrass (Digitaria spp.), goosegrass (Eleusine indica), yellow foxtail (Setaria glauca), green kyllinga (Kyllinga brevifolia), yellow nutsedge (Cyperus esculentus) and annual bluegrass (Poa annua) are among the most common and troublesome turf weeds in Delaware. Weeds such as these compete with desired plants for space, water, light, and nutrients and can harbor insects and diseases. They can be host other pests such as plant pathogens, nematodes, and insects. Weed management is an integrated process in which good cultural practices are employed to encourage desirable turfgrass ground cover and in which herbicides are intelligently selected and judiciously used when needed. For more information on controlling weeds in the Mid-Atlantic Region, including herbicide recommendations, see:
- Weed Control in Turf. University of Delaware Extension.
- Broadleaf Weed Control in Established Lawns. 2005. University of Maryland.
- Herbicides for Crabgrass and Goosegrass Control in Turf. 2008. University of Maryland.
- Guide to Controlling Weeds in Cool Season Turf. 2016. University of Maryland Extension.
9.3.3 Turf Insects/Arthropods
Many arthropods (especially insects and mites) live in turfgrass and the ornamental plant beds on golf courses. Some are beneficial (e.g. pollinators, decomposers, and natural enemies) or are aesthetically attractive (e.g. butterflies), while others may be nuisance pests or may negatively affect plant health. Arthropods can cause various types of damage to turfgrass, depending on where they attack the plant. Annually recurring insect pest groups on Delaware golf courses include species such as armyworms, cutworms, nuisance ants and bees, and annual white grubs.
9.3.4 Annual Bluegrass Weevil
The annual bluegrass weevil (ABW) is a beetle of the weevil family and a pest of short-cut, highly maintained turf in the Northeastern and Mid-Atlantic regions. Damage often is first observed at the edges of greens and fairways with a high proportion of annual bluegrass (Poa annua). Most damage is caused by larvae, which may go unnoticed for many weeks. Significant damage from first-generation ABW generally becomes obvious in late May or early June and often is mistaken for other problems. Damage from second-generation ABW occurs in late July until early August. Evidence of ABW damage includes damaged stems, which can easily be pulled away from the crowns, and hollowed stems with sawdust-like frass (excrement), which is a key diagnostic feature. Older larvae may be detected by cutting into the turf and examining the area between turf and thatch.
An appropriate early-season damage threshold is 30 to 80 larvae per square foot. That threshold decreases as turf gets more stressed. Monitoring methods include soap flushing the turf with a solution of dishwashing detergent (0.5 ounces detergent per gallon water) to force adults to the surface. Other monitoring techniques include black light traps, pitfall traps, vacuuming adults, growing degrees days, weevil trak, and phenological indicators.
In addition to chemical control, cultural management options should be considered, primarily converting from a susceptible turf species to one that has increased tolerance to ABW. Perennial ryegrass is resistant to ABW. Because ABW overwinters in pine litter and leaves, removing this material may help to reduce populations. Proper nutrition and irrigation often help mask symptoms of ABW damage.
For more information on ABW biology and control in the Mid-Atlantic, see Biology and Management of the Annual Bluegrass Weevil. 2005. University of Maryland.
Plant-parasitic nematodes adversely affect turfgrass health by debilitating the root system of susceptible turfgrass and decreasing water and nutrient uptake efficiency. Additionally, weakened turf favors pest infestation, especially troublesome weeds that necessitate herbicide applications. Over time, turf in the affected areas thins out and, with severe infestations, may die. The roots of turfgrass under nematode attack may be very short, with few, if any, root hairs, or they may appear dark and rotten. Turfgrass usually begins showing signs of nematode injury during additional stresses, including drought, high temperatures, low temperatures, and wear. Cultural practices and nematicides can help control nematodes.
9.3.6 Biological Controls
The biological component of IPM involves the release and/or conservation of natural predators, such as parasites and pathogens, and other beneficial organisms. Biofungicides, or formulations of living organisms used to control the activity of plant pathogenic fungi and bacteria, are commercially available. Natural enemies (including ladybird beetles, green lacewings, and mantids) may be purchased and released near pest infestations. Areas on the golf course can also be modified to better support natural predators and beneficial organism populations.
9.3.7 Conventional Pesticides
A pest-control strategy using pesticides should be used when the pest is causing or is expected to cause more damage than what can be reasonably and economically tolerated. Pesticides should be evaluated on effectiveness against the pest, mode of action, life stage of the pest, potential human health hazards, non-target effects, potential off-site movement, and cost. A control strategy should be implemented that reduces the pest numbers to an acceptable level while minimizing harm to non-targeted organisms or the environment. In addition, the use of pesticides should be consistent with guidelines to reduce resistance in pest species. Lastly, pesticides must always be used as directed on the product label, as required by state and federal law.
9.4 Record Keeping and Evaluation
It is essential to record the results of scouting in order to develop historical information, document patterns of pest activity, and track successes and failures. Records of pesticide use are required by DDA regulations, but for IPM purposes should include additional information, such as monitoring records, weather records, cultural management logs, and pest response.
9.5 IPM Best Management Practices
Basic IPM Best Management Practices
- Develop a written IPM plan for your golf course. (Available resources for writing an IPM plan include the GCSAA and Greengolfusa.com.)
- Select turfgrass cultivars recommended for use in Delaware and best suited for the intended use and the environmental conditions of the specific site.
- Correct soil physical and chemical properties that may impact turfgrass health and its ability to resist pests.
- Evaluate the potential impact of the timing of cultural practices and fertilizer applications on the incidence of pest problems.
- Divert traffic away from areas that are stressed by insects, nematodes, diseases, or weeds.
- When chemical control is necessary, follow Delaware recommendations to select the most effective pesticide with the lowest toxicity and least potential for off-target movement for a given weed, pathogen, or insect.
- Document all IPM-related activities, including pesticide usage.
Pest Identification Best Management Practices
- Identify key pests on key plants.
- Determine the pest’s life cycle and know which life stage to target (e.g. for insect pests, whether it is an egg, larva/nymph, pupa, or adult).
- For diseases, correctly identify the disease pathogen. This often involves sending samples to diagnostic clinics.
- Identify weeds accurately.
- Consider targeted pest control measures rather than blanket applications of pesticides.
Monitoring Best Management Practices
- Monitor prevailing environmental conditions for their potential impact on pest problems.
- Train personnel how to regularly monitor pests by scouting or trapping.
- Identify alternative hosts and overwintering sites for key pests.
- Correctly identify the specific disease, weed, and/or insect problem to ensure appropriate control measures.
- Assess pest damage when it occurs, noting particular problem areas, such as the edges of fairways, shady areas, or poorly drained areas.
- Document when the damage occurred. Note the time of day, date, and flowering stages of nearby plants.
- Map pest outbreak locations to identify patterns and susceptible areas for future target applications.
Pest Threshold Best Management Practices
- Establish threshold levels for key pests and document in the written IPM plan.
Weed Control Best Management Practices
- To prevent weed encroachment, adopt or maintain cultural practices that protect turfgrass from environmental stresses such as shade, drought, and extreme temperatures.
- To reduce weed infestation, address improper turf management practices, such as the misuse of fertilizers and chemicals, improper mowing height or mowing frequency, improper soil aeration, and physical damage and compaction from excessive traffic.
- Fertilize adequately to sustain desirable color, growth density, and vigor and to better resist diseases, weeds, and insects.
- Weed-free materials should be used for topdressing.
- Address damage from turfgrass pests such as diseases, insects, nematodes, and animals to prevent density/canopy loss to weeds.
Disease Control Best Management Practices
- Ensure that proper cultural practices and traffic control that reduce turfgrass stress are used.
- Correct conditions that produce stressful environments for the turf (e.g. improve airflow and drainage and reduce or eliminate shade.)
- Fungicide use should be integrated into an overall management strategy for a golf course.
- Apply a preventative pesticide to susceptible turfgrass when unacceptable levels of disease are likely to occur.
Insects/Arthropods Control Best Management Practices
- Release insect-parasitic nematodes to naturally suppress insect pests such as white grubs.
- For insecticide application aimed at soil insects, irrigate turfgrass before and/or after an application, in accordance with the label.
Annual Bluegrass Weevil Best Management Practices
- Reduce the amount of annual bluegrass in infested areas.
- Remove overwintering habitat (i.e. pine litter and leaves).
- Monitor in the spring as adults migrate from overwintering and time insecticide applications for adults at peak migration time.
- Replace turf with species less susceptible species annual bluegrass weevil.
Nematode Control Best Management Practices
- When nematode activity is suspected, an assay of soil and turfgrass roots is recommended to determine the extent of the problem.
- Increase mowing height to reduce plant stress.
- Irrigate deeply but infrequently.
- Use proper amounts of N, P, and K fertilizers at the appropriate times of year.
- Reduce or eliminate other biotic and abiotic stresses when nematodes are compromising the root system and plant health.
Biological Controls Best Management Practices
- Identify areas on the golf course that can be modified to attract natural predators, provide habitat for them, and protect them from pesticide applications.
- Install flowering plants that can provide parasitoids with nectar, or sucking insects (aphids, mealybugs, and soft scales) with a food source.
- Avoid applying pesticides to roughs, driving ranges, or other low-use areas to provide a refuge for beneficial organisms.
Conventional Pesticides Best Management Practices
- Train employees in proper pest identification and pesticide selection techniques.
- Follow a selection process to select the best site- and pest-specific product with the lowest potential to have off target effects.
- Purchase, mix, and apply only the quantity of pesticide needed in order to avoid disposal problems, protect non-target organisms, and reduce costs.
- Follow the label and read the entire pesticide label before handling or applying pesticide.
- Spot-treat pests whenever appropriate.
- Make note of any environmental hazards and groundwater advisories included on the label.
- Rotate pesticide chemistries (modes-of-action) to reduce the likelihood of resistance.
- Follow guidelines and advice provided by the Fungicide Resistance Action Committee (FRAC), Herbicide Resistance Action Committee (HRAC), and Insecticide Resistance Action Committee (IRAC).
Record Keeping and Evaluation Best Management Practices
- Determine whether the corrective actions effectively reduced or prevented pest populations, were economical, and minimized risks. Record and use this information to assist in making similar decisions in the future.
- Observe and document turf conditions regularly (daily, weekly, or monthly, depending on the pest), noting which pests are present, so that informed decisions can be made regarding the damage they are causing and what control strategies are necessary.