Scalping
Excessive removal of turf leaves by close mowing. Results in a brown, stubbly appearance.
|
Sclerotia
Seed-like, compact masses of fungal tissue that allow fungi to survive unfavorable conditions. Small round or threadlike structures which are produced on the diseased turf or in the thatch layer by certain fungi.
|
Sedge
Sedges are members of the Cyperaceae family. They are upright plants with fibrous roots and stolons. Sedges can be distinguished from grasses and rushes by stem shape. Sedges generally have solid triangular stems, whereas rushes have solid round stems and grasses have hollow round or flattened stems. Sedges have leaves in groups of three, while grasses have leaves in groups of two. Sedge leaf edges are usually rough; leaf sheaths are tubular, not split; the collar is usually indistinct; auricles are absent; and ligules are small or absent. Like rushes, sedges are considered semi-aquatic, and will be found where there is an abundance of water but are also found in drier areas. Sedge flowers are usually one to many spikelets.
|
Seed Blend (Blend, Seed)
A combination of two or more cultivars of the same species, e.g., Rebel and Falcon tall fescue.
|
Seed Mixture (Mixture, Seed)
A combination of two or more species; e.g., Kentucky bluegrass and perennial ryegrass.
|
Seed, Certified
A seed lot inspected to meet minimum standards and to ensure trueness to type for a given cultivar.
|
Selective Herbicide (Herbicide, Selective)
Herbicide that kills/injures some plants without harming others.
|
Semiarid Turfgrass
Turfgrasses adapted to grow in semiarid regions without irrigation, such as buffalograss, gramagrass, and wheatgrasses.
|
Sepals
The floral organs found at the base of the flower; usually green and somewhat leaflike.
|
Sessile
Directly attached without a stem or stalk.
|
Sheath
The basal portion of the leaf surrounding the grass stem. In grass plants, it is usually split with overlapping edges, but may also be open or closed.
|
Site of Action
The way that a pesticide works to kill an organism.
|
Slicing
Penetration of turf in a vertical plane by series of solid flat tines.
|
Slow Release Nitrogen (Nitrogen)
Nitrogen is the most important element in turfgrass culture. It is required for the formation of chlorophyll which is then used for photosynthesis. Nitrogen is also found in numerous plant proteins, amino acids, enzymes, and vitamins. Nitrogen is primarily absorded through the roots in the nitrate (NO3-) form, but can also be taken up in the ammonia form (NH4+). Nitrogen rich fertilizers are often used to enhance and maintain turf appearance (green color) and density.
Nitrogen sources are normally referred to as quick release and slow release.
-
Quick release sources (e.g., ammonium nitrate) are water-soluable and produce fast turf greening. These sources have a short residual and a high burn potential.
-
Slow release sources of nitrogen (e.g., IBDU, Urea formaldehyde) are typically organic materials broken down over time by soil microorganisms. These materials produce slow slow turf green-up, have a long residual, and low burn potential.
|
Soil
A substrate of material made up of rocks and minerals, organic matter, and water. Soil makes up the top layer of the surface of the earth. Properties of soil include texture, color, structure and bulk density. Soil is a constantly evolving structure, based upon weather, plant material, water and other inputs.
|
Soil Compaction (Compaction)
Soils that are subject to heavy traffic are prone to compaction (compression). Compacted soils reduce drainage,
increase runoff, and inhibit root growth. Aerifying (aeration) helps to alleviate compaction.
|
Soil Erosion (Erosion)
Whenever water, as intensive rainfall or irrigation, falls on bare soil surfaces in gardens or lawns, sand, silt, clay, and organic matter may be moved away from the site. The potential for erosion increases with slope, but unless there is runoff, raindrops cannot do much damage. It is the transportation of soil particles and organic matter in runoff that causes concern. This transported sediment can choke lakes and carry chemicals into waterways, making them unsuitable for recreational fishing, boating, or swimming. Everyone, including the urban resident, farmer, gardener, recreational enthusiast, and taxpayer must pay for the damage.
|
Soil Fumigant (Fumigant)
A volatile material that vaporizes and destroys pests, e.g., methyl bromide.
|
Soil Sterilant (Sterilant)
Any chemical applied to the soil that prevents growth of plants for a long time.
|
Solution
Physically uniform mixture of two or more liquids.
|
Spike
Seedhead in which the side branches are attached to the main axis without a stalk.
|
Spiking
Penetration of turf in a vertical plane by series of solid round tines.
|
Spore
A microscopic seed-like reproductive unit that can germinate and give rise to more fungi. Spore masses appear as fuzzy or jelly-like growths on the diseased tissue, and usually appear when the turf is wet or humidity is high.
|
Spots
Localized areas of diseased turf less than 4 inches in diameter.
|
Spreader
An ingredient that helps pesticides come in closer contact to the plant surface.
|
Sprig
A stolon or rhizome used to establish a turf.
|
Stamen
The male part of a flower that produces the pollen.
|
Stand symptoms
Stand symptoms are an easily visible indication of some problem affecting the turfgrass. These are most easily observed by standing and looking across the turf area. Stand symptoms may be the result of nutritional deficiencies, drought or other environmental stresses, improper cultural practices, chemical injury, or pests. Man-made and environmental turf damage are often confused with pest-induced injury. Determining the cause of the problem is critical to effective turf management. When used in reference to diseases, there are several different types of stand symptoms, which basically describe the pattern of the disease on the lawn or landscape: circles, spots, patches, rings, or irregular, non-patterned symptoms across the turf stand.
|
Sterilant
Any chemical applied to the soil that prevents growth of plants for a long time.
|
Sticker
An ingredient that helps pesticides stick to plants.
|
Stipule
Appendage at the base of a leaf.
|
Stolon
An above-ground creeping stem that can produce roots and shoots at each node.
|
Sulfonylurea (SU) Herbicide (Herbicide, Sulfonylurea (SU))
A class of herbicides with high levels of activity at low application rates. In general, the SU herbicides are used to control annual bluegrass and perennial ryegrass during bermudagrass spring transition, as well as certain broadleaf weeds. Some members of this herbicide family also provide control of nutsedge and kyllinga species, and also dallisgrass when used with MSMA. The mode of action for this class is inhibition of the ALS enzyme that is used in biosynthesis. These chemicals are rapidly translocated, and resistance can become an issue. Examples include sulfosulfuron (Certainty), metsulfuron (Manor), trifloxysulfuron (Monument), foramsulfuron (Revolver), and rimsulfuron (TranXit GTA).
|
Sulfonylurea Herbicide (Herbicide, Sulfonylurea (SU))
A class of herbicides with high levels of activity at low application rates. In general, the SU herbicides are used to control annual bluegrass and perennial ryegrass during bermudagrass spring transition, as well as certain broadleaf weeds. Some members of this herbicide family also provide control of nutsedge and kyllinga species, and also dallisgrass when used with MSMA. The mode of action for this class is inhibition of the ALS enzyme that is used in biosynthesis. These chemicals are rapidly translocated, and resistance can become an issue. Examples include sulfosulfuron (Certainty), metsulfuron (Manor), trifloxysulfuron (Monument), foramsulfuron (Revolver), and rimsulfuron (TranXit GTA).
|
Surfactant
Several classes of chemicals that reduce the interfacial tension between water and plant material or other liquids. Classes of surfactants include wetting agents, spreaders, and stickers. Types of surfactants include anionic, cationic, and nonionic. The most common type of surfactant used in herbicide applications is nonionic.
|
Symptom
The visual characteristics associated with a given disease.
|
Systemic Herbicide (Herbicide, Systemic)
Herbicide that is taken up through contact with the leaves or through the soil (via contact with the roots) and is moved throughout the plant to kill the whole plant.
|