Introduction to Turfgrass

Introduction

Turfs were developed to enhance the environment

Turfs are important in human activities Turfs provide many benefits to those who

plant them

Benefits (Environmental)

Control wind and water erosion of soil Reduce glare, noise, air pollution, heat buildup Increase property values Increase aesthetic value Oxygen conversion

Benefits (Recreational)

Baseball, football, golf, hiking, polo, rugby, soccer, etc.

Provide cushioning effect reducing injuries Benefit health by its use in recreational

activities

Benefits (Ornamental)

Beauty and attractiveness Provide pleasant environment

History of Turfgrass

Turf referenced in Biblical literature Date to medieval times (200-800 A.D.) Mowing machine first invented in 1830 (before that mowed by

livestock) Earnest research on turf began in 1880 (Beal, Michigan State) Most major advances have occurred since 1950’s

– Improved cultivars released– Pesticides developed specifically for turf for weed, disease, and

insect control– Formulation of fertilizers specifically for turf– Major advances in the mechanization of cultural practices

Importance

Cover nearly 32 million acres in the US Largest irrigated crop in the U.S

– That’s 3 times as much as all the corn! Over 28 billion dollars spent each year on

lawns in the US– That’s about $1200/household (of an approx. 25

million households) One of the only crops that increase with

urbanization

Terminology

Sod – refers to plugs, blocks, squares, strips, or rolls of turfgrass plus adhering soil that are used for vegetative planting.

Green – Smooth, grassy area maintained for golf, bowling, other sports.

Lawn – Ground covered with fine textured grass and kept closely mowed.

Sward – Grassy surface of a turf that may be composed of more than one species.

Turf – A covering of closely mowed dense vegetation, usually grass, growing intimately with an upper soil stratum of intermingled roots and stems.

Turf Quality

Uniformity Density Texture Growth habit Smoothness Color

Controls of Turfgrass Quality(Inherited characteristics)

Susceptibility – disease, nematodes, insects

Tolerance– Heat, cold– Drought, flood– Shade– Wilt– Salinity– Wear

Recuperative potential Primarily used for selection purposes

Controls of Turfgrass Quality(Environmental characteristics)

Light Temperature Water Nutrient level Soil aeration Traffic Can be controlled at least partially through

management/culture

Climactic Zones of Turf Adaptation

YOU ARE HERE!

Cool Season Grasses

Start growth at 5 °C (41 ° F) Fastest growth rate when temperatures are between

10-25 °C (50-77 ° F) In climates that have relatively mild/cool summers,

two periods of rapid growth (spring and fall) They retain their color well in extreme cold and

typically grow very dense, carpet like lawns

Warm Season Grasses

Start growth at temperatures above 10 °C (50 ° F) Grow fastest when temperatures are between 25 °C

and 35 °C (77-95 ° F) One long growth period (over the spring and

summer) Go dormant in cooler months, turning shades of tan

or brown Typiclaly drought and heat tolerant Temperatures below -15 °C (5 °F) can kill most

warm season grasses.

Cool Season

Kentucky bluegrass (Poa pratensis) Perennial ryegrass (Lolium perenne) Creeping bentgrass (Agrostis stolonifera) Tall Fescue (Festuca spp.) Buffalo grass (Buchloe dactyloides)

Cool Season

Kentucky bluegrass (Poa pratensis) Perennial ryegrass (Lolium perenne) Creeping bentgrass (Agrostis stolonifera) Tall Fescue (Festuca spp.) Buffalo grass (Buchloe dactyloides)

Kentucky Bluegrass

“Blue” for the characteristic bluish color of a field when allowed to flower and produce seed.

“Kentucky” due to its widespread occurrence in the relatively fertile limestone soils in Kentucky.

One of the best species for unshaded areas in temperate humid climates

Very aggressive under favorable conditions, spreads rapidly by rhizomes

Looks best mowed at ¾ to 1 ½ inches

Perennial ryegrass

Takes its name from European name (“Rai” grass)

Not related to cereal grain Germinates quickly (7 days or less) Rapid establishment Not shade tolerant Best mowed at 1 ¼ inches or higher

Creeping bentgrass

Most commonly used grass on golf putting greens

Strongly developed growth habit of creeping via surface stems that root freely at the nodes

Not well suited to shade Easiest to injure, difficult to kill Best when mowed very short (1/2 inch or less)

Tall fescue

Useful for more extensive grassed areas that are not maintained as lawns.

Deeply rooted Broad, flat leaves Drought tolerant Grows well in full sun and partial shade Excellent for areas where other grasses will not grow Mow at 2 or more inches

Warm Season

Zoysia grass (Zoysia japonica) Bermuda grass (Cynodon dactylon) Centipede grass (Eremochloa ophiuroides) St. Augustine grass (Stenotaphrum

secundatum) Bahia grass (Paspalum notatum)

Botanical Composition

Monostand – One species of the same variety.

Blend – Two or more varieties of the same species.

Mixture – Two or more species

Methods of Establishment

Seed –The mature ovule of a flowering plant containing an embryo, sometimes an endosperm, and a seed coat

Sprig – A single turfgrass stem (stolon, rhizome, tiller, or combination) usually with attached roots and leaves

Sod – Turf harvested as a thin layer composed of a living, dense population of grass palnts with shortened or shallow roots in a growth medium

Plug – A small, usually round piece of turfgrass with adhering soil used in vegetative propagation.

Morphology

Morphology (continued)

Crown – Compacted series of nodes from which shoots and adventitious roots arise at the base of the culm (stem) of grasses

Tiller – A lateral shoot, or stem, usually erect, arising from a crown bud, common in grasses

Morphology (continued)

Rhizome – Usually horizontal, jointed, commonly underground stem of grasses that forms both roots and leafy shoots at its nodes; often enlarged by food storage; may originate from the main stem or from tillers

Stolon – A slender horizontal stem (or shoot) that grows horizontally about the soil surface and is capable of developing leaves, roots, and stems at its tip or at nodes; may originate from the main stem of tillers

Morphology (continued)

Bunch type– Ryegrass– Tall Fescue– Spread very slowly through tillers

Spreading– Rhizomes (Kentucky bluegrass, some Tall

fescues)– Stolons (Creeping bentgrass)– Both (Bermudagrass, Zoysia grass)

Maintenance

Fertilizing– Fertility should be maintained at proper levels. Soil tests

should be carried out, and a minimum of 3 lbs./1000 sq.ft. of N should be applied per year

– Do a soil test! Mowing

– 1/3rd rule: Only mow off a maximum of 1/3rd the height of the grass at one time

Irrigation– A good system should be able to deliver 1” of water in a 24

hour period

IPM

Integrated pest management – An organized program in which the best

management methods available (including chemical, physical, cultural, biological, and regulatory) are used to keep pest populations below the economic and/or aesthetic injury level while avoiding adverse effects on humans, wildlife, and the environment.

Typical Steps for IPM

Identify key pests to be managed in the turfgrass ecosystem Define the turfgrass management unit – the turf ecosystem Develop reliable monitoring technuques, a critical component of

any IPM program Establish aesthetic thresholds Evolve descriptive and predictive models of what pests are

most likely to occur, when they should be expected to appear or become active, and the amount of damage that may take place

Develop an effective and economical turf management strategy

Management tactics

Genetic - breeding Cultural – Uses fertilization, irrigation, site selection, plant

selection and/or sanitation to prevent pest problems in the first place. Biological

– uses beneficial organisms (insects, bacteria, etc.) to control pests. Endophytes Bt

Physical or mechanical – A preventive strategy. It includes screens or other barriers, temperature and humidity modification, traps, physical repellents and hand removal of weeds.

Chemical - pesticides

Management tactics

The most important thing you can do is to monitor and observe the management unit for weed, insect pest, and disease problems.

Close observations, assessment of pest and environmental problems, detailed record-keeping

Make sure that if you are going to do something that there is a definite need to do it.

Turfgrass Entomology

Cutworms

Black cutworm - Dark gray to black with a pale stripe down the back, but with few other distinguishing markings.

Bronze cutworm - Dark brown to black on the upper side of the body and paler on the underside. The upper surface has three narrow yellow stripes and a broad white-yellow stripe running down each side

Variegated cutworm - Grey to brown with an orange lateral stripe and a series of darker lateral markings. A row of yellow or white dots runs down the middle of the back

Black Cutworm

Adults (moths) migrate northward from southern states in early spring and deposit clusters of 10 to 20 eggs on grasses and weeds

Wind patterns (which affect the migration and ultimate distribution of the moths) and local environmental conditions strongly influence the severity of black cutworm infestations

As many as three generations per year

Bronze cutworm

Overwinter as eggs which hatch in early spring

Fully-grown larvae are present by late April and pupation occurs during mid-August

Single generation each year

Variegated cutworm

Overwinter as partially-grown larvae and resume feeding as grasses start to green up in the spring

Adults begin to appear in late spring and deposit up to 2000 eggs in clusters of 100 or more under the sheaths of grass blade

2 to 4 generations of variegated cutworms each year

Cutworm Damage

• Cutworms feed at night, cutting grass blades near the soil surface

• Small circular dead or dying spots that increase in size to 1 to 2 inches in diameter as the worms mature

• Occasionally cause severe damage on golf course greens (especially bentgrass) where they live and feed around the openings made by aerification

Determining if cutworms are present:

1 tablespoon of 1% pyrethrins or 1/4 cup of lemon-scented household detergent in two gallons of water over one square yard of turf

Birds, and/or animals foraging in turf areas is often an indication of cutworms

Examination of cutworm or armyworm-infested turf will reveal clipped or skeletonized grass blades mingled with green fecal pellets

Control

Weather is warm and humid, fungal diseases sometimes infect the insects, reducing infestation levels

Parasitic flies and wasps lay their eggs on cutworm and larvae

Predation by birds Chemical control: Perethrins, Marathon,

Dylox, Dursban, Talstar,etc.

White Grubs

Immature stages of scarab beetles White grub larvae are white and soft-bodied, with

brown heads Feed primarily on roots 6 legs and the body is curved into a C-shape Pupate underground, later emerging as beetles Adults are heavy bodied, with widened front legs that

are used for digging through the soil Adults dig out of the soil, mate, burrow into the soil to

lay their white eggs to repeat the cycle

Symtomology

In general, 10 to 12 grubs per square foot or more will eat enough roots to cause dieback of the turf

Turf will turn brown and can be easily turned back like a carpet

Various animals are attracted to white grubs for food (Raccoon, skunks, birds, armadillos) at levels as low as 3-5 grubs/sq.ft.

Determining if there is a problem

Scout at the proper time: late July/early August Select areas known to have the problem in the past

that are sunny, warm, and well-watered You will have to dig to see the grubs Quickly count the #, and replace sod Determine if the numbers are high enough to treat

Control of white grubs

Chemical (insecticidal)– In general, mortality in excess of 60 percent is considered

to be adequate for control– Insecticide longevity in the soil ranges from about a week to

several months – Low persistence = quick kill, can be applied curatively– High persistence = longer kill (up to 3 weeks), should be

applied when adults are laying eggs– Must be watered into the root zone (1/2” irrigation)– Diazinon, Merit, Dylox, Mach II, etc.

Control of white grubs

Cultural– Back off on irrigation in June and July (less

attractive to egg laying adults)– Insecticidal nematodes– In years of high rainfall, there may be no need to

treat as eggs will be spread over a large area, reducing threshold levels

Billbugs

Billbugs are weevils that attack turfgrasses and other crops

Frequently confused with white grubs 2 most important: Bluegrass and hunting

– Bluegrass billbug: cool season turfs– Hunting billbug: warm season turfs

Adult billbugs are poor fliers (localizes damage)

Billbugs (continued)

Larvae feed on roots Adults feed on stems, stolons, and crowns (sawdust) Overwinter as adults, about 1/4 inch long and

blackish Very hard shelled and have an elongated “snout”

which houses chewing mouthparts Adults are active on warm winter days and

throughout the spring

Billbugs

Insert their eggs into stems and leaf sheaths Larvae burrow in until too big then migrate to

root zone (1/4 to ¾ in. in size) Larvae can be found at any time of the year,

although they are most common in June and July

Billbug control

Adult vs. grub stage control– Adults: foliar sprays (chlorpyrifos aka. Dursban) – Larvae: Usually controlled in June and July by

soil drenches (just like other white grubs)