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PA: Penn State Extension Cool-Season
Turfgrass Pest Management (Category 7)
Rated A+
What are three approaches to pest control?
- cultural control
- chemical control
- biological control
Why are cultural practices key factors in pest management?
If cultural practices are done correctly, then turfgrasses are healthy so that weeds, diseases, and other pests have trouble gaining a foothold. Any pest activity that does occur is masked by vigorously growing turf.
What are proper cultural practices for healthy turfgrass?
It begins with a selection of high quality turfgrass seed or sod that is well suited for the site followed by sound planting practices. The other proper cultural practices are mowing, watering, and fertilizing.
Explain "Healthy turfgrass is tolerant turfgrass."
Healthy turfgrass can withstand some pest problems without losing its quality or attractiveness. It is almost more capable of recovering when problems do occur.
Define "Biological control"
Using living organisms or their products to reduce pest populations (example: mites, nematodes, bacteria, and fungi)
Define "Chemical control"
Include not only pesticides that kill pests, but also repellents, attractants or pheromones, and insect growth regulators
Define "cultural control"
Manipulating the planting, growth, and maintenance of turf or a landscape to make it less attractive to a pest and reduce pest activity.
Define "endophyte"
A turfgrass plant that has fungus within it that is toxic to some insects
Define "pest resistance"
A pest population that can survive or "resist" the chemical's effect. When this happens, the chemical fails to provide adequate control and is no longer useful.
Define "preventative application"
Prevent a pest outbreak by making an application before the problem appears
Define "reactive (curative) application"
"Cure" a pest problem after the problem is noticed. Most insects can be adequately controlled after they are discovered, but before they cause significant damage.
Fine (red) fescue turfgrass
"You select a blend of three improved tall-fescue cultivars containing endophytes. These tall fescues are resistant to chinch bugs, billbugs, and turfgrass caterpillars. The three cultivars are chosen because they also have differing resistance to brown patch disease, which is a problem on tall-fescue turfgrass."
cultural control: You picked a blend of three improved tall-fescue cultivars that provided natural resistance. This is a preventative control that reduced your need to react with pest infestation with chemical or biological controls.
What kind of "control" does this scenario describe?
"As summer continues, you keep the young turfgrass mowed to a height of three inches by frequent mowing, never removing more than 1/3 of the blade at a time. Fertilizer is applied to improve the light color and density. No evidence of crabgrass yet but you see some dandelions and thistle."
cultural control. You used proper mowing height and fertilizer rates were used.
What kind of "control(s)" does this scenario describe?
"A walk across the lawn in the fall reveals less than a dozen broadleaf weeds. These are spot- treated with a selective herbicide spray. You apply a fall fertilizer."
Chemical and Cultural Control: You spot sprayed a selective herbicide to control the weeds, but your cultural practices prevented a weed infestation.
Define "amine"
A salt form that formulates into a liquid product (herbicide). Amines are more water soluble
Define "annual vs. biennial vs. perennial"
Annuals complete their life cyles in one year (grows from seed, flowers, produces new seeds, and dies within one year). Biennials need two years to complete their life cycle (the first year they grow leaves, roots, and store energy then in the second year the flowers and seeds produce as well as the plant dies). Perennials persist year after year (they reproduce and spread by a variety of ways, especially in the soil through roots and stems underground).
Define "chemical control strategies"
Two chemical control strategies to control grassy weeds: preemergence herbicides and postemergence herbicides
Define "Cultural control strategies"
Proper mowing to the proper height, watering deeply and infrequently, and appropriate fertilizing will help reduce weeds.
Define "Ester"
A salt form that formulates a liquid product. Esters are more effectively absorbed by plants and are a better choice under cool conditions when plants are less active. They are more volatile and prone to vapor drift. Avoid using them in high temps to reduce injuring desirable plants.
Define "Preemergence vs Postemergence"
Preemergence is to prevent newly germinated weeds from growing and should be applied in early spring. Postemergence is applied after crabgrass and other grassy weeds appear (secondary control strategy).
Describe cultural control strategies used to manage grassy and broadleaf weeds
- Fertilizing (thick turfgrass crowds out weeds)
- Mowing (higher cut turfgrass shades out weeds)
- Watering (deep moisture keeps turfgrass thick during dry periods)
- Core Aerifying (breaks up hard soil to reduce compaction and improve the uptake of water and fertilizer for a healthier lawn)
List possible reasons a herbicide application may fail to provide control
- Uneven application (skips or gaps in the application leaving turfgrass without chemical)
- Improper Rate (too light, perhaps due to a mixing or applicator error, improper calibration, or incorrect measurement of the treated area)
- Unusual weather affecting the barrier (excessive rainfall or irrigation or lack of rainfall or irrigation)
- Poor turfgrass management (turfgrass too tall or mowed soon after material is applied)
- Renovation work (dethatching, repairs, and reseeding may destroy the barrier)
- Soil disruptions (soil cracking, animal digging, etc.)
List guidelines to maximize herbicide effectiveness and minimize injury to turfgrass
To Avoid Control Failure...
- During hot, dry weather water deeply the day before application and apply 1/2 inch of water two days after the treatment
- Apply the materials when air temps are between 70 and 85 degrees.
- Follow the label directions for timing of mowing and delay if necessary
To Avoid Injury to Turfgrass...
- Carefully read the product label to find out if the herbicide will injure seedling turfgrass
- In case of over-application, irrigate with one inch of water as soon as possible.
Where do weeds come from?
- bird droppings contain weed seeds
- windborne seeds from surrounding areas
- bits of stem/roots/or seeds brought in on shoes, pets, etc.
- seeds already in the soil
- bare patches or sparse growth can allow germination
- creeping stems from surrounding weedy lawns
Four ways you can start right with newly seeded or sodded turfgrass
- Use nonselective herbicides
- Fumigate the soil
- use weed-free materials
- know when to use herbicides
Herbicide in Newly Planted Planted Turf: Siduron
Controls germinating grassy weeds
Herbicide in Newly Planted Planted Turf: Bromoxynil
Controls emerged broadleaves in the seedling stage
Herbicide in Newly Planted Planted Turf: Mesotrione
Controls broadleaves and a few annual grasses
Read the scenario and answer the questions:
"Mrs. Zimmerman notices dandelions springing up in her lawn even though you have been using herbicides to manage them. How can you explain the presence of these weeds in her yard?"
Wind and birds may continue to carry seeds into Mrs. Zimmerman's yard. The seeds may remain alive in the soil and germinate after many years. Remind Mrs. Zimmerman you are controlling the weeds and it is not possible or desirable to eliminate all.
Read the scenario and answer the questions:
"Mr. Kelly is building a new home. He tells you he does not think he will need your services anymore because he is starting his new lawn from seed. He does not expect to have weed problems if he starts from seed. What services could you offer Mr. Kelly?"
Tell Mr. Kelly that this is a good time to control weeds- before planting. Nonselective herbicides can be used to kill all plants at a site and provide a fresh start. However, seeds in the soil will not be affected. In addition, use seeds, mulch, and straw that are weed free.
Define: "Annual Bluegrass"
Winter annual Grassy Weed
A light green, bunch-type winter annual grass. The small, open-panicle seedheads are easy to see during most of the growing season. Most seeds germinate in late summer or early fall. Usually dies during hot, dry conditions if not irrigated
Define: "Crabgrass"
Summer annual Grassy Weed
Commonly found in turfgrass- two species: large and smooth. Seedheads are divided spikes that project like fingers from the stem producing thousands of seeds in late summer. Seeds germinate in the spring and crabgrass dies after the first frost in early fall leaving dead patches in the turf.
Define: "Foxtail"
Summer annual Grassy Weed
A light-green, leafy, summer annual grass that reaches maturity in midsummer. Often confused with crabgrass, but it is less common. It can be prolific under low-fertility conditions and high mowing heights.
Define: "Nimblewill"
Perennial Grass
blue-green perennial grass that is common in cool season lawns during the spring. Forms dense patches. Nimblewill grows rapidly during the warm summer months and turns brown or tan in the winter.
Define: "Tall Fescue"
Environmental conditions, stage of plant growth, and plant structures have a major influence on weed control. These factors join to make the summer the most difficult time to control some troublesome broadleaf weeds, often referred to as "summer spoilers." They are better adapted to harsh summer conditions than the desirable turfgrasses. Some of these weeds have thick or waxy leaves that prevent moisture loss.
Define: "Dandelion"
Perennial Rosette/Upright Broadleaf Weed
Forms a long, narrow, and strongly lobed leaves and produces thick taproots that can penetrate several inches into the soil. Bright yellow flowers are produced on long stems in the spring.
Define: "Plantain, broadleaf"
Perennial Rosette/Upright Broadleaf Weed
A large (3 to 6 inch diameter), low-growing, perennial weed. Leaves grow in a rosette and are spoon-shaped with wavy margins. Seedheads are 5 to 10 inches long and cling tightly to the stalk. Thick root that grows deep into the soil.
Define: "Plantain, buckhorn"
Perennial Rosette/Upright Broadleaf Weed
Large weed grows in a rosette fashion. Leaves are long and much more slender. Individual leaves have smooth, wavy margins and taper to a point. Prominent veins run lengthwise down the leaf. Seed stalks are long and end in small compact seedheads.
Define: "Thistles"
Perennial OR Biennial Rosette/Upright Broadleaf Weed
Spiny, notched leaves. Typically occurs when turf is mowed.
Define: "Oxalis"
Perennial OR Annual Rosette/Upright Broadleaf Weed
Sometimes called yellow woodsorrel is a light-green, upright weed that can be a summer annual or perennial. Each leaf has three leaflets. Distinct heart shape and flowers are bright yellow with five petals. As flowers mature, they lose their petals and form banana-shaped seedpods.
Define: "Common chickweed"
and blue green with margins that are not serrated. Each leaf is elliptical, tapering to a round tip. One distinct feature is the papery sheath at the base of each lead. Flowers are very small and white.
Define: "Prostrate Spurge"
Summer Annual Creeping or Prostrate Broadleaf Weed
Spreads in a prostrate fashion over the soil surface or over desirable grass surfaces. Leaves are oppositely arranged, small, with a reddish-brown mark or enlarged spot on the upper surface. When broken or cut, the stems ooze a white, milky substance. Flowers are very small and pink or white.
Define: "Ground ivy"
Perennial Creeping or Prostrate Broadleaf Weed
Low growing, creeping weed. Leaves are oppositely arranged on stems and are round or kidney shaped. Distinct veins and sparse hairs. Stems are square, creeping, and long. Flowers are blue or purple and trumpet shaped.
Define: "Violet"
Perennial Creeping or Prostrate Broadleaf Weed
Wild violets are persistent. Grow upright and spread by a means of thick underground stems. Leaves are heart-shaped with serrated margins. The leaf surface is shiny and waxy. Flower petals are purple and the center of the flower is white or yellow.
Define: "White Clover"
Perennial Creeping or Prostrate Broadleaf Weed
Three leaflets, each with a small white mark in the center. Stems grow above ground and root at the nodes. Produces white, compact flowers.
Read the scenario and answer the questions:
"Mr. Smith calls you in late July. He asks if you could please do something about all the dandelions in his lawn. His daughter is getting married next month and wants an outdoor reception to be held at his home. What can you do for Mr. Smith?"
You can try a postemergence herbicide, but this is not the best time to control dandelions. The dandelions in Mr. Smith's lawn are maturing and will not respond to chemical control as well as they would have when they were young, actively growing, and first emerging in early spring.
Define: "overwintering stage"
It is the stage when some organisms pass through or wait out the winter season, or pass through that period of the year when "winter" conditions (cold or sub-zero temperatures, ice, snow, limited food supplies) make normal activity or even survival difficult or near impossible.
Define: "sampling techniques"
A variety of techniques to inspect the turf closely to find the insect and determine how many are present. (examples: visual inspection, irritant or flushing solution, flotation, square foot samples, or pitfall traps)
Define: "subsurface feeders"
Insects such as white grubs and nearly mature billbug larvae that feed in the soil and thatch zone
Define: "surface feeders"
Insects such as chinch bugs, sod webworms, armyworms, cutworms that feed on leaves and stems
What does insect damage look like to turfgrass?
Insect damage to turfgrass may appear as yellowing, browning, or thinning of the grass stand.
What are the two groups of insects that damage turf?
- Surface pests- such as chinch bugs, sod webworms, armyworms, cutworms that feed on leaves and stems
- Subsurface Pests- such as white grubs and nearly mature billbug larvae that feed in the soil and thatch zone
What is a nuisance pest?
Insects such as ants and cicada killer wasps. They are typically more of a nuisance than a real threat to the health of turfgrass or people.
How do you correctly identify an insect problem?
- Observe symptoms of damage on the turf
- Locate signs of insect activity
- Locate the actual damaging insect life stage
- Observe the presence of other insect life stages
What are some insect control methods?
- Cultural controls: irrigation, fertilizer, thatch reduction equipment, changes in soil pH, resistant turfgrass varieties.
- Biological control: Using predacious insects to eat the turf pests or parasitic insects to attack the eggs and larvae of pests, and infect the pests with microbes which will kill them. Using biorational insecticides.
- Chemical control: When a pest population exceeds a threshold level and when no other options are available, insecticides are preventive or curative action can be used to treat.
Surface Insect Activity Clues
- Grass blades are chewed off or have notching
- turf is yellow, burnt-orange, or brown
