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Common Diseases

Dollar Spot

Dollar Spot

Dollar Spot is a common disease deriving its name from the size and shape the infection that centers on short-cut bent grass. On longer-cut turf grass, infected centers of completely killed turf grass may be several inches in diameter.

Viewed from a distance, Dollar Spot resembles various other turf problems, especially on higher-cut grass species. Closer inspection, however, reveals the characteristic hourglass symptoms on the individual blades of grass. Regardless of grass variety or species, the disease is first evident as yellow or yellow-green blotches. These will soon appear water-soaked, and within 24 hours the blotches will bleach to a light-tan or straw color. In the early morning, a white cobwebby growth of fungal thread is often visible in the infected center. Overall, the most reliable symptom for diagnosis includes the presence of constricted straw-colored areas with reddish-brown margins on the leaf blade.

Avoid mowing wet turfgrass, which only spreads the fungus pathogen, creating extensive damage by smearing spores throughout your lawn and opening its vascular system to further disease that can damage the health of your lawn.

Avoid watering in the evening or at night.

Anthracnose

Anthracnose

Anthracnose occurs both as a foliar blight and a rot of the crown, stem base, and roots. Anthracnose typically occurs in the mid-summer, attacking the leaves and stems of most cool-season turfgrass species. Anthracnose basal rot can occur during the spring, summer, and fall, developing in the crowns, stem bases and roots.

Anthracnose appears in irregular yellow or bronze patches of diseased turf. Symptoms on individual plants first appear as yellow or red lesions on the oldest leaves, and then progress to blight the younger leaves and shoots. These lesions can enlarge and merge to kill the entire leaf blade. The fungi commonly infect grass blades from the tip down, especially infecting grass that has been freshly mowed. During cool, wet periods- or during hot weather on closely cut lawns- water-soaked lesions will rot the stems. The lesions will become bleached, girdling the tiller, scattering individual or small patches of plants to turn yellow and die. This can especially occur during warm to hot weather, especially on dry soil when the turf and atmosphere are wet or very humid.

Brown Patch

Brown Patch

Brown patch appears as irregularly shaped enlarging patches of blighted turf grass, a few inches to 2 feet in diameter. At first, it's purplish-gray, but then fades to light brown as the withered leaves of your lawn dry out and die. During periods of warm, humid weather, dark purplish rings bordering the diseased area can be seen early in the morning.

The fungus begins to be active when the average daily air temperature is 73°F. When temperatures reach 80° to 85°F, particularly in a moisture-saturated atmosphere, Brown Patch symptoms can become quite severe within hours.

The disease may even occur under conditions of low soil-moisture content, but a moisture-saturated atmosphere will cause a Brown Patch outbreak in epidemic proportions, threatening large areas of your lawn. On leaves that are already infected, the disease will have an active growth in the 80° to 85° temperature range.

Copper Spot

Copper Spot

This fungus was initially reported as a disease of sorghum, but has since been found to also cause a problem on bent grasses. It is relatively rare in Pennsylvania.

On the leaves of turf grass plants, the disease first appears as small reddish lesions, which soon enlarge and becomes dark red. Blighting of the entire leaf soon results as these lesions merge.

The disease, seen from a distance, first appears as a copper-colored patch, 1 to 3 inches in diameter. Intensity of this coloration increases during wet weather, due to the pink spore masses which are produced. Cooper spot is often confused with dollar spot; the latter has a bleached, straw-colored appearance. Both diseases may occur simultaneously in the same stand of turf grass.

Cooper spot is primarily a warm, wet, weather disease; active growth begins when temperatures reach the 70 to 75 range. The fungus spores are spread by splashing water, germinate rapidly, and cause new leaf lesions to appear within a relatively short period of time.

Fairy Rings

Fairy Rings

Myths and superstitions about the origins of fairy rings have persisted for centuries. In Holland, the rings mark places where the devil churns his butter. In France, entrance into a fairy ring might mean an encounter with a giant toad. In England, building a house on land scattered with fairy rings was considered a good omen.

But despite their charming mythology, they will litter your lawn. Many soil-inhabiting fungi can cause fairy rings. Although the rings vary in size and shape, they are usually distinct circles or semi-circles of turf grass that are darker green and faster growing than the surrounding grass. These stimulated grass bands may range from 4 to 12 inches wide, with a diameter of 3 to 200 feet. Characteristically, mushrooms or toadstools can appear in the rings in later summer during periods of high soil moisture.

Fairy rings are classified in three main types. Some fairy rings are detected only by the presence of the ring of mushrooms or puffballs. Another type of ring exists where the grass is stimulated by the release of methane gas created by the decomposition of organic matter within the soil. The most devastating type of fairy rings kill the turf, leaving a circle of expose soil with stimulated grass sprouting on the inside and outside margins.

Gray Snow Mold

Gray Snow Mold

This disease usually first appears when snow thaws in the spring, commonly found in lawn areas of greatest snow accumulation. The most noticeable symptoms include bleached, white crusted areas of grass, leaving the blades dead, bleached and matted together. These bleached areas can range in size from several inches to several feet in diameter.

The chief diagnostic feature of gray snow mold is grass stained with hard, dark-brown to light-brown pinhead-sized fungus bodies. These are embedded in the leaves and crowns of infected grass plants as patches of disease, threatening the health of your lawn. In most cases the fungus does not kill the grass or the roots, but it causes death to the grass blades and weakens the plant structure making your lawn susceptible to problems later in the year.

The fungus will survive in the thatch, clippings and crown area of the turf until the following winter. Under the cover of snow, these bodies germinate, growing a fungus that induces infection. Gray Snow Mold seldom occurs, except under snow cover when the soil is not frozen. Of course, this is typical in areas where snow falls on unfrozen soil and melts gradually, trickling water down the turf, feeding diseases and fungi that will litter the blades of your grass.

Leaf Spot

Leaf Spot

Leaf spots are circular to elongate, straw-colored, and surrounded by reddish-brown borders. During long periods of wet weather, many of the spots may be surrounded by a margin of water-soaked tissue.

Severe infection often causes the leaves to wither. A diseased stand of bent grass may give a drought- injured appearance, even though soil moisture is adequate.

Red Leaf Spot is a warm, wet weather disease, usually first seen in late May or early June and reaching it speak in late July and August. The leaf blighting and "droughtstricken" phase of the disease usually occurs during this period, particularly after longs periods of wet weather.

On bent grass, the disease is first seen as smoky-blue, irregularly shaped turf areas, varying from 1 to 4 feet in diameter. Soon after, the grass plants yellow and die. Finally, these areas appear water-soaked and matted down. This disease may appear in the spring on home lawns as well as on bent grass greens and fairways.

On the leaves, the first symptoms are minute yellow flecks, which soon progress to irregularly shaped, water-soaked blotches.

Pink Snow Mold

Pink Snow Mold

This disease occurs when temperatures are in the 40 to 50 F range. Pink fungus spores accumulate on the leaves of infected grass plants under snow cover. Individual grass blades may seem nearly red or sickly pink. Another diagnostic feature is the absence of the pinhead brown sclerotia, common with Gray Snow Mold. It usually attacks only the leaves. However, under conditions ideal for disease development, the fungus can kill the crowns and roots as well.

Pink Snow Mold is a much more severe disease than Gray Snow Mold, especially when cold wet weather in the fall results in the development of the disease prior to snow cover. The fungus will continue its activity from winter into spring. Under these conditions, damage to the turf is likely to be severe and long-lasting. Snow mold damaged areas are prone to later growing season disease issues, threatening your lawn's health later in the season.

Powdery Mildew

Powdery Mildew

Powdery mildews generally present more serious problems to cereals and forage grasses than turf grass. At times, however, powdery mildew can damage your turfs density and aesthetic beauty, especially on shaded areas of susceptible Merion Kentucky bluegrass.

The disease appears first as small, superficial patches of ugly white to gray-white fungus growth on the leaves and sheaths. The growth occurs mainly on the upper surface of the leaf, but it may eventually engulf the entire leaf. Once the fungus penetrates your grass, a yellow lesion develops, later turning tan or brown as the vitality of your lawn is killed. In advance stages, older, lower leaves are often completely covered by mildew. In severely infected areas, the turf is a dull, pale white, as if dusted with lime.

Powdery mildew prefers cool, humid, cloudy weather, with temperatures about 65 F. The mildew occurs in severe form during the late fall and early spring.

Pests

Pests

We can help identify if you need our assistance. All of the recommendations to this point in the book have been designed to make your lawn healthy enough to resist pests naturally. Each practice you follow will reduce the amount of pesticides that might be necessary as a last resort.

Before resorting to pesticide use, be sure the problem is not simply a function of poor soil conditions, tree roots, bad drainage, foot traffic shade or other causes that can be corrected in other ways.

Basic Principles:

When you've determined that pesticides are required, you still can significantly reduce their environmental impact by following these basic rules:

1. Accurately identify the weed, insect, or disease condition. If in doubt, make a sketch or take a sample to show your garden store salesperson or county extension office.

2. Purchase the right product for the problem you've identified. Avoid "all purpose" products that contain ingredients your lawn and the environment do not need.

3. Use only commercially packaged branded products. By law, all commercial pesticides have to be tested and EPA registered.

4. Use only the amounts specified in the directions. Exceeding label amounts in an attempt to increase your success hurts your lawn and the environment, wastes money, and is against the law.

5. Target the applications only to the areas that require them.

6. Keep notes on when and where problems recur, so that preventive measures can be applied at the ideal time, and only where needed.

Identifying Pests:

The presence of weeds is obvious, and the varieties are easily identified. Insects and animals, on the other hand, require more careful observation and identification. The following is a list of common pests and their observable symptoms:

Armyworms

Armyworms have plump segmented bodies that range from ¾ to 1 ½ inches. Their color is dull and varies from greenish – gray to brown. A yellowish – white mid-strip runs the length of its back and ends in an inverted "v" on the head. Three light-colored longitudinal stripes run along the length of each side. The Armyworm had three pairs of prominent legs and additional prolegs or unjointed projections.

The adult moth is dull brown and had a wing span of nearly 1 ½ inches. Eggs are laid on grass, shrubs and other low-growing plants. Larvae hatch in about a week and start eating immediately. Thousand of Armyworms may be produced within small areas. Damage first occurs in bright, warm sunlight. As the name implies, Armyworms move in "hordes" destroying most vegetation in their path. Attacks by Armyworms leaves the turf ragged and bare in a very short time.

Armyworms are unpredictable. One year they may go unnoticed, while the following year they might do extensive damage. However, when they do appear it is usually in great numbers.

Japanese Beetle

The beetles appear in June and are abundant during July and August. They feed on the fruit, blossoms, and foliage of fruit trees, shade trees, and ornamentals. The beetles are about ½ inch long with metallic green bodies, coppery-brown wing covers, and 6 small patches of white hairs along the sides and back of the body. The Japanese beetle has a complete generation each year and spends about 10 months of the year in the soil as a grub.

The adult beetles start emerging from the soil during the last week of June and increases in numbers until they reach their peak in July. Emergence drops off sharply about mid-August, but a few beetles may still be around through September.

The female beetles deposit their eggs in moist soil. The eggs need ample moisture to promote hatching. Dry soil conditions during July and early August are not attractive to the females for egg deposition and hinder hatching of the eggs. Eggs normnewally hatch in about 10 days.

The tiny grubs start feeding on humus immediately. As they increase in size, they move close to the soil surface and start feeding on grass roots. They grow rapidly and will be about 1 inch long by late September. Most injury occurs during the fall and early spring as the mature grubs feed near the surface. The Japanese beetle grub can be distinguished from other grubs by the arrangement of hairs on the raster.

When the soil temperature starts to drop in the fall, they move down 6 to 12 inches in the soil where they over winter. In April, they move back up to the root zone and continue feeding. In late May and June, they change to the pupal stage and start emerging as adult beetles in late June.

Symptoms of grass damaged by grubs are dead, brown patches which can usually be rolled back like a carpet. The roots are severed by the grubs and there is nothing to anchor the turf to the soil. Such areas are often spongy when walked on. Damaged areas may be noticeable anytime from Spring until the grass browns off for Winter.

Those aren't 'Dragon Flies' … They're Crane Flies!

Yuck… what is that big bug? Well, it's not a dragon fly or a mosquito, it's a Crane Fly.

Crane Flies can either lay their eggs in water or in the soil. The females tend to find areas for their eggs near wet or moist areas, such as mud, wet moss, or under dead leaves. The female will place her abdomen just below the water's surface and the eggs sink to the bottom. Other females will place their abdomens right below the surface of the soil to lay their eggs.

From an egg form they become larvae (worm-like) that can be brownish, grayish, or even cream colored and their length varies from ½" to 3" inches. During the larvae stage Crane Flies are also known as "leatherjackets". The larvae stage is where the Crane Fly does most of its damage by eating on the roots and crowns of turfgrass. The damage will become noticeable during March and April. It can also be damaging to one's lawn if the larvae are present, because the moles and skunks will tear up a lawn looking to eat the larvae.

Next is the pupae stage what is also known as the "resting period". This is when the larvae hatch from the "leatherjackets" and transform into the Crane Fly. This resting period occurs during the winter months so come Spring, the Crane Fly is out and flying again.

The adult Crane Fly abdomen is about 2 ½" inches long and the wing span is about 3" inches wide. The adults' main purpose is to mate and lay eggs. The adults only live a few days and the females will lay their eggs within 3 to 17 days. The adults are basically harmless; they don't eat, bite or sting. The adults are essentially just a huge nuisance.

If you would like to add this protective service to your lawn service treatments, please contact our office today.

Pythium Blight

Pythium Blight

Pythium blight is among the most destructive of the turf grass diseases, capable of completely destroying established stands within 24 hours after the onset of favorable environmental conditions. More than 148 species are susceptible to this blight, including annual bluegrass, Bermuda grass, colonial bent grass, creeping bent grass, Kentucky bluegrass, rough bluegrass, Italian ryegrass, perennial ryegrass, velvet bent grass, tall fescue, red fescue and red top.

Lesions on individual leaves are water-soaked-green or straw color with no distinct margin separating diseased from healthy tissue. The infected area of turf appears as a circular spot varying from less than one inch to several inches in diameter. In the early morning, the infected plants seem water soaked with a cottony growth on matted leaves. With the onset of lower relative humidity, the growth disappears and the grass blades shrivel and die.

The fungus becomes destructive with an abundance of moisture and warm temperatures (85 F and higher), although infection can occur with temperatures as low as 68 F. Disease development is greater at highly unbalanced nitrogen levels, and in calcium-deficient soils.

Red Thread

Red Thread

Red Thread can cause severe damage to any lawns cultivated in the cooler, humid regions. Its chief characteristic is a pink colored fungus tissue that adheres to the surface of the shoots and leaves of the grasses. In wet weather, these fungus outgrowths are very conspicuous, stretching from leaf to leaf, binding the parts of the plant together.

In early stages, infected tissues are water soaked, but later they become dry and lose their color. The patches of blighted grass range in diameter from two inches to three feet, often appearing ragged due to the fairly high population of unaffected leaves.

Field diagnosis of red thread is easiest when the disease is in its final stages of development. The ends of the leaves will have fine bright coral thread-like fungus structures, damaging the health of your lawn.

 

Rust Fungus

Rust Fungus

Orange colorations indicate rust fungus, and they can affect the stems, leaves, and crowns of your lawn. Low temperatures will arrest its development. Spread and infection is slight during late spring and early summer when your grass is growing rapidly. But symptoms become more evident in the late fall when the growth of your lawn is slower. The ultimate environment for stem rust is 8 to 16 hours a day of high light intensity with air temperatures of 85° to 95°F.

Stem Rust occurs when Kentucky bluegrass is grown. The cultivar Merion is extremely susceptible.

Leaf Rust is widespread, generally found throughout the summer. It's usually of minor importance. In heavily infected years, the leaf blades are distinctly yellowed.

Crown Rust is a common disease of Italian ryegrass, perennial ryegrass and fall fescue. The bright yellow fungus is often found wherever those turf varieties are grown.

Rust can become a major nuisance turning 'Everything Orange'. Rust can be reduced by core aeration and overseeding more resistant grass types or by use of a fungicide.

Strip Smut

Strip Smut

The smut diseases of turf grass are fungi which affect leaves, stems and seed heads. Those attacking vegetative portions of the plant can be very destructive, resulting in the shredding and death of the plants. Where turf grasses are grown for seed production, outbreaks of smut in the floral tissues can cause considerable decrease in yields.

Infected turf grass usually grows slowly and appears stunted. Long yellow-green streaks develop on the leaves of the affected plants. The streaks become gray. Later, black dusty spore masses form stripes that sometimes extend the entire length of the leaf and into the sheath. The leaves die from the tip downward. Distinct browning often occurs during hot dry weather as the leaves become shredded.

Extended periods in the 50 to 60 F. range are most conducive to stripe smut development. Plants grown at 90 F for prolonged periods usually do not show symptoms. The disease is more severe on older turf areas than in newly seeded or seedling areas, and is more prevalent in varieties that tiller profusely. Stripe smut is most severe during cool dry springs when the fungus can keep pace with grass growth.

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