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Turf (3b): Turf Pest Management - Test Your Knowledge

Terms in this set (60)

Name some of the factors turfgrass managers must consider when setting pest management priorities.
Turfgrass management professionals must consider human safety, environmental safety, turf use(s), efficacy, and economics.
Why do pest management thresholds in turf vary?
Pest thresholds vary from site to site because they depend on site characteristics and uses. For example, there may be zero tolerance for pests of any sort on a gold green. On the other hand, there may be no great need to control pests in the grassy areas of an industrial site. However, setting thresholds in some sites - like a school athletic field or playground - may not be simple and clear-cut. A thick, uniform surface is ideal for play areas, for optimum utility and safety. This, in turn, means the tolerance for pests is low. However reliance on pesticide use may not be acceptable for some recreational sites, especially if the primary users of that site are children.
What is the first, most basic step to take to manage pest problems? Explain your answer.
Use Best Management Practices (BMPs) for initial design, installation, and maintenance programs. Begin by selecting high quality, disease- and insect-free turfgrass. When possible, plant or install resistant varieties. Choosing the right variety for the site and use(s) is essential. Next, good cultural practices provide the best conditions for plant health.
Why should you focus your attention on key pests, key varieties, or key locations?
They are most likely to cause problems. Key pests, varieties, and locations require special monitoring and care.
What is a "key pest"?
A key pest is one that often reaches population densities that justify management, and/or is capable of causing unacceptable damage at relatively low densities, and/or attacks and damages turfgrass(es) in conspicuous or valuable areas.
What is a "key variety"?
A "key variety" has a special "high profile" use. A variety that sustains damage from pests on a regular basis, or has a particular pest that can kill or disfigure it in low densities, would also be considered a "key variety."
Describe a site that would be considered a key location.
Key locations are heavily used or are significant in some way. Areas where turfgrasses have chronic problems with pests, and/or areas that are near something or someone requiring special protection are "key locations."
Name several things you need to make an accurate diagnosis of a pest problem.
Description of the type and extent of plant damage, identification of the pest, familiarity with the life cycle of the pest, a good estimation of the size and distribution of the pest population, and an assessment of whether it is increasing or decreasing.
Define the term "Integrated Pest Management." List IPM tactics used in turfgrass pest control.
Integrated Pest Management refers to the use of a combination of pest control tactics. IPM programs use many types of techniques in a single plan or strategy to reduce pests and keep their damage to an acceptable level. IPM tactics include monitoring and early detection, sanitation, and cultural, mechanical (physical), biological, and chemical control methods.
What is biological control? Give one example.
Biological control involves using some aspect of the pest's biology to control it. One example is the uyse of natural enemies, biological agents that control a pest. Turfgrass managers can preserve or encourage natural enemies already present in the system. Alternatively, they can introduce commercially produced biological organisms. Biological control also includes the use of pheromones or juvenile hormones to control insects.
What are some factors that influence the success of biological controls?
Biological control agents usually target specific pests. Biological control agents must be able to move to - or be placed in contact with - the target pest. For that reason, application techniques influence success. Adoption of biological control measures usually takes careful planning and timing. Finally, biological control organisms must be able to tolerate conditions at the site. To be sustainable, they must persist from season to season.
What is cultural control? List several cultural control tactics used in turf.
Cultural control measures disrupt the normal relationship between pest and host in order to prevent or suppress an infestation. Cultural controls make the pest less likely to survive, grow, or reproduce. They can involve changing the turf grass environment or its physical condition. Cultural control measures may also change the behavior of a pest. In turf, variety selection and proper establishment are basic cultural control measures. Other practices employed in turf include thatch management and proper mowing, watering, and fertilization regimes. Aerating soil and cultivation practices that improve water infiltration (spiking, vertical mowing, or coring) can help.
What is mechanical control?
Mechanical controls use some mechanical device such as a trap or barrier to control pests.
What is sanitation? Give two examples.
Sanitation is general cleanliness. Sanitation reduces the levels of pathogens and other pests in the turf grass environment. Using pest-free seed, sprigs, or sod is a sanitation strategy. Careful disposal of diseased clippings is another. So are cleaning and disinfecting tools and equipment, and taking care to avoid spreading disease by foot traffic.
Why is the timing of a pesticide application important?
To be effective, pesticides must be applied correctly and at the proper time and rate. In many cases, pesticides need to be used at a certain stage in a pest's life cycle. Applying them too early or too late is a waste of time and money. In addition, poorly timed applications may pose a threat to the turf you intend to protect as well as to other organisms and the environment.
Explain the difference between a preventative and a curative pesticide application.
A preventative application is made before the problem appears. A curative application is made after the problem is noticed.
What is phytotoxicity? How can you recognize the problem?
Phytotoxicity is injury or damage to a sensitive plant caused by a chemical exposure. Symptoms of phytotoxicity include: death of rapidly growing tissues; stunting or delayed development; misshapen or distorted stems, leaves, or fruits; russeting or bronzing of leaves or fruit; dead spots or flecks on leaves, dead leaf tips or margins; and dead areas between leaf veins.

You might suspect phytotoxicity if you see plant damage but no sign of pest presence. Another warning sign is injury that occurs suddenly or over a short period of time that does not spread from plant to plant. Consulting spray records might give you a clue if pesticide use is causing phytotoxic effects. Records may document the use of a pesticide near a sensitive plant showing signs of injury.
Describe some pesticide uses that might result in phytotoxicity.
-Application of a pesticide during adverse environmental conditions.
-Use of a pesticide contrary to label directions (ex. wrong side or wrong rate).
-Movement offsite from a target area to a sensitive area (ex. drift or runoff).
-Accumulation of persistent residues in the soil; or on the plant.
How can you avoid causing phytotoxicity when using pesticides?
Be certain the plant you plan to treat is listed on the product label. Measure and prepare the chemical carefully. Use the proper rate and application techniques. Follow label directions for the number and timing of applications. Apply and store pesticides according to label directions. Do not treat stressed plants. Direct pesticides to the target. Do not allow offsite movement. Do not treat plants when they are subject to extreme heat or cold.
How can you minimize clover mite injury?
One of the best ways to limit clover mite injury is to provide adequate water to sites that have a high risk of injury. Watering both suppresses winter mite populations and helps turfgrass to tolerate injury.
If you are going to apply a pesticide to control clover mites, would you use a spot or broadcast treatment? Explain your answer.
Usually, clover mite damage is limited to warm, dry areas along sun-exposed sides of buildings. Spot treatments are effective when directed to sites clover mites use for feedinga nd egg laying. Areas to treat include lower foundation walls and tree trunks as well as adjacent sun-exposed turf. Spot applications reduce pesticide use.
How can you manage cutworms with minimal environmental impact?
When possible, select a resistant endophyte-enhanced variety of fescue or ryegrass. Do not mow turf any lower than 2.5 inches (6.25 cm). Remove clippings after mowing because adult cutworm moths lay eggs at the tip of grass blades. If you use insecticides, apply them late in the day because cutworm larvae feed at night. Consider using beneficial nematodes, especially in sites where continual reinfestation occurs.
What turf management and maintenance practices minimize problems with chinch bugs?
Manage (minimize) thatch. Avoid using susceptible varieties. Do not plant fine (red) fescue in full sun. Choose endophyte0enhanced fescue and ryegrass. Do not apply high-nitrogen fertilizer applications in spring.
What should you do to control fall armyworms?
You can manage fall armyworms with entomopathenogenic nematodes or insecticides. Monitor larval populations by using a disclosing soap solution. Apply insecticides at the first sign of damage. (Damage usually does not occur until late in the season.) Light irrigation several hours before an insecticide application may help to draw larvae to the surface. Apply insecticides when larvae are active near the surface - in morning or early afternoon.
What turf management and maintenance practices minimize problems with sod webworms?
Plant resistant endophyte-enhanced varieties of fescue and ryegrass. Avoid close mowing because damage is seldom noticeable in turf > 2.5 inches (6.25 cm) in height.
Describe some sod webworm control strategies.
You can control sod webworms with insecticides or entomopathenogenic nematodes. Effective times for insecticide applications are:
-spring and early summer (to control larvae that overwintered), and
-late June and early September, about two weeks after adults are seen. (Young larvae are most susceptible to insecticide
True or false: Thatch can interfere with white grub control tactics.
True. Most white grub larvae live and feed below ground. Thatch will reduce the penetration and efficacy of surface-applied insecticides.
What are the action thresholds for white grubs?
The threshold for green June beetle is 2 to 5 grubs per square foot. For Japanese beetles and May and June beetle, populations of 6 to 10 grubs per square foot are high enough to warrant control measures. Thresholds for black turf ataenius (BTA) are not firm. However, 20 to 30 BTA grubs per square foot will usually cause an unacceptable amount of damage.
Describe some effective control tactics for white grubs.
White grub larvae are most susceptible to insecticides in the early stages. For Green June beetle, Japanese beetle, and May and June beetles, insecticides for grub control are most effective if applied in early to mid-August. Make spring applications to control the first generation of Blue turf ataenius (BTA) grubs in early May - when horsechestnut or Vanhoutte spirea are in bloom. Make applications to control the second BTA grub generation, if necessary, in August. All grub control insecticides should be watered in.

Black turf ataenius (BTA) adults overwinter in Virginia. An early spring insecticide application, made before the adults can lay eggs, can control them and the first generation of grubs. BTA adults live in turf thatch. Insecticide applications made to control them should not be followed with watering.

Milky spore (Bacillus popilliae) products will control Japanese beetle grubs. Note that using a grub-control insecticide on a site treated with milky spore will slow the spread of disease and is counter productive. White grubs can also be controlled by some types of entomopathenogenic nematodes and the insect pathogenic fungus Beauvania bassiana.
What sanitation practices can prevent the spread of turfgrass diseases?
Removing and disposing of clippings; making sure irrigation systems are clean; using only disease-free seeds, sprigs, and sod; controlling insect or mite vectors; cleaning and decontaminating tools and equipment; and taking care not to "track" diseased plant material or spores on shoes.
List some strategies that may be used to manage fungal diseases in turf.
Sanitation, use of disease-resistant grasses, good cultural practices, and fungicides. (At present, no biological control agents are known to be effective.)
Which would you expect to be most effective for melting-out (a disease that affects leaves, collars, and crowns): a contact or a penetrant fungicide?
A penetrant fungicide. Penetrant fungicides are active at the site of placement. However, they also enter the underlying tissue. Thus, a penetrant would be more likely to be effective in the collar and crown areas. (A contact fungicide affects only the portions of a plant covered by the spray.)
Describe some ways to prevent or minimize the incidence of powdery mildew on turf.
Increase air flow and/or decrease shade.
Why should turf management professionals monitor weather conditions?
Outbreaks of some diseases can be predicted by weather monitoring. You may be able to predict outbreaks of Fusarium blight by monitoring nighttime minimum temperatures. Warm, humid nights often signal development of Helminthosporium leaf spot, Pythium blight, and Rhizoctonia blight of cool-season turf. Red leaf spot and red thread outbreaks occur in warm, wet weather. Melting-out usually occurs in cool, wet weather.
Why will thatch management help to reduce the incidence and severity of turfgrass diseases?
Many of the fungi that parasitize the leaves and crowns of turfgrasses can live as saprophytes in thatch. For that reason, thatch buildup results in increased amounts of inoculum. This, in turn, causes an increase in disease incidence and severity.
Name a disease that may be managed by keeping thatch thickness below 0.5 inch (1.3 cm).
Managing thatch is an effective way ti minimize problems with both Fusarium blight and red leaf spot.
How can you manage Fusarium patch (pink snow mold)?
Maintain soil pH in the acidic range. In soils that are naturally acidic, apply lime in the spring versus late in the growing season. Do not leave grass uncut in the fall. Rather, raise the cutting height 20 percent at the end of the growing season to allow for better cold weather survival, but continue to mow until top growth ceases. In areas where pink snow mold is common, apply a preventative treatment within two weeks of the first predicted snowfall of the season. Follow with midwinter and spring applications as weather permits. In snow-free regions, if this disease is a problem, treat just before the beginning of cold, wet weather. Continue at 7 to 10 day intervals as long as the weather remains cold and wet. Some fungicides will manage ("cure") this disease.
Many turf grass diseases can be managed, at least to some degree, by fertilization programs. Name one.
Helminthosporium leaf spot, melting-out, Pythium blight, red leaf spot, and red thread are all impacted by nutrient inputs.
Several turfgrass diseases can be managed, at least to some degree, by decreasing the length of time leaves are wet. Name one.
Problems with Pythium blight and Rhizoctonia blight (of both cool- and warm-season turf grass) can be reduced by removing water from leaves.
Describe some ways to manage nematodes.
A good way to manage nematode damage is to reduce other stress factors. Nematicides can be applied to established turfgrass. Use namaticides only on properly labeled sites. Follow label directions with extreme care.
What are some steps to take to ensure success when using a nematicide?
For maximum effectiveness, apply nematicides only after the soil temperature at 4 inches (10 cm) depth reaches 60F (16C) or greater. Irrigate before and after application. Cultivation practices that improve water infiltration (spiking, vertical mowing, or coring) can help. After treatment, employ cultivation and watering schedules that will maximize root growth and development.
How can you manage mollusk pests (slugs and snails)?
Properly registered pesticides and some homemade baits will control these pests.
You had a problem with crabgrass in a lawn last season. What would you do to manage crabgrass this year?
There is probably a reservoir of crabgrass seed on site. So, start by applying a preemergence herbicide in early spring. Next, do all you can to promote the growth of the turfgrass in the lawn. Monitor grabgrass. If patches of crabgrass do appear, make postemergence spot treatments and seed the treated areas.
How can you manage herbicide applications in turf while avoiding injury to valuable ornamentals in adjacent landscapes?
In general, manage herbicides by placement, timing, and/or product selection. Consider the herbicides's activity spectrum: whether it has contact or systemic activity. Direct sprays to target weeds. Use preemergent herbicides around established plants. Use a selective product that will control problem weeds but will not affect the landscape plants. Manage drift. Do not use products with activity on broadleaf weeds under trees or shrubs unless you are certain they will not leach.
How do contact herbicides differ from systemic herbicides?
Contact herbicides affect only treated areas. Systemic herbicides are absorbed by and move within the plant.
What type of weeds may be controlled effectively by contact herbicides: annual weeds or perennial weeds? Why?
Contact herbicides are most often used to control annual weeds. They are effective in controlling annuals which have relatively small root systems. As a rule, annuals do not have enough stored energy to regrow after the above-ground parts are killed.
What is the best time to apply a contact postemergence herbicide to an annual weed?
Treat annual broadleaf weeds when they are small, generally less than 4 inches tall. Treat annual grasses before tillering.
When should preemergence herbicides be used for annual weed control?
For winter annuals, apply products in the late summer or fall. Apply preemergents for summer annual weed control in the winter or early spring.
What do you need to consider before choosing an herbicide?
Consult the label to be sure the product can be used on the site. Next, be sure that the product will control the target weed(s) and can be used at the time and in the manner you intend.
How can you use herbicides selectively to affect only target plants?
You can be selective with herbicides by managing application placement and timing. IN addition, you can choose a product that is contact versus systemic, or one that has a narrow spectrum (affects only certain types of plants) versus a broad-spectrum.
How may total vegetation control products cause harm when used near landscapes?
They can injure trees and shrubs if their roots lie under the treated soil, or if the product moves offsite into their root zone.
In general, which is best for control of perennial weeds: a reemergence or a postemergence herbicide?
Most preemergence herbicides do not control perennial weeds. Systemic postemergence herbicides are best for control of perennial broadleaf weeds. Nonselective herbicides can be used to control perennial grasses.
Describe some cultural control strategies for weed management in turf.
Most weeds will not be able to invade and compete with thick, healthy, well-established stands. To produce a healthy stand, chose a species and variety suited for the site and use. Follow recommended establishment practices. Once a stand is establishment practices. Once a stand is established, manage is correctly. Base your thatch management and watering, fertilization, and mowing programs on the grass species and/or variety, the site characteristics, and the site's use(s). Prevent or treat for insect and disease pests. Manage traffic, if possible. Overseed thin areas. Seed bare patches. Do not let weeds go to seed. Long-handled pincer-type weed pullers will remove some weeds in lawns when soil is moist. Mowing can prevent some weeds from going to seed.
Why do you need to know a weed's life cycle to manage it effectively?
Like most pest organisms, weeds are more vulnerable to control measures ( including herbicides) at certain times. Most weeds should be treated when actively growing. For example, preemergent herbicides must be applied in late winter or early spring to control summer annuals. However, they must be applied in late summer or early fall to control winter annuals.
What is the difference between a preemergence herbicide and a postemergence herbicide?
Preemergence herbicides are applied to soil before weeds germinate. They are absorbed by the roots of the germinating plant or by the emerging shoot as it pushes up through the soil. As a rule, preemergence herbicides do not affect established plants. Postemergence herbicides are applied to emerged, growing weeds. They injure or kill emerged weeds after after being absorbed.
What factors affect the success of preemergence herbicides?
Preemergence herbicides need to be activated (moved into the top inch or two of soil where weed seeds germinate) by rainfall or irrigation. You may need to irrigate after applying certain granular herbicides. Irrigation (or rainfall) will also ways the chemical off the turf grass and reduce the chance of blade injury. When using preemergence herbicides, be sure the application is uniform. If liquid preemergence herbicides are applied to tall grass and the grass is mowed soon after, the herbicide may not reach the soil surface in effective amounts. Removal of clippings may make matters worse. Soil disruptions such as detaching, raking, or animal activity can generate gaps where weed seeds can germinate.
What is the best way to treat perennial broadleaf weeds?
Generally, systemic postemergence herbicides.
Describe how to control perennial grassy weeds with herbicides.
Most perennial grasses are controlled by nonselective herbicides. Selective herbicides are usually not an option because of the similarities between grassy weeds and desirable turf grasses. If the perennial grassy weed grows in clumps, use spot treatments. Note that control of weeds with rhizomes, tubers, and/or stolons usually requires repeated applications. In some cases, renovation is the best solution.
Describe when and how to use post emergent herbicides in turf.
Apply postemergence herbicides to actively growing weeds in established turfgrass stands. Treat when the weather is warm and soil moisture is adequate. Avoid applications under hot, dry weather. Postemergence herbicides are not very effective on weeds under drought stress. Be sure the application is uniform and coverage is good. Certain postemergence herbicides are absorbed slowly. A rain occurring a few hours after application could wash such a chemical off foliage before it is absorbed. Do not apply such chemicals if there is a chance of rain following application. Consult the product label for specifics. Delay mowing for three to five days after a spray application.
Several turfgrass diseases can be managed, at least to some degree, by mowing regimes. Name one.
Fusarium patch (pink snow mold), Helminthosporium leaf spot, and melting-out are affected by mowing height.
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