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1969 EC69-1833 Lawn Diseases in the Midwest J. L. Weihing

M. C. Shurtleff

R. E. Partyka

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Weihing, J. L.; Shurtleff, M. C.; and Partyka, R. E., "EC69-1833 Lawn Diseases in the Midwest" (1969). Historical Materials from University of Nebraska-Lincoln Extension. 3952. http://digitalcommons.unl.edu/extensionhist/3952

This Article is brought to you for free and open access by the Extension at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Historical Materials from University of Nebraska-Lincoln Extension by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. AC?R I I I J ~ e:7 North Central Regional Extension Publication No. 12 f09'-/8.33 c I I Lawn Di in the MIDWEST

Agricultural Extension Services of Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Ne· braska, North Dakota, Ohio, South Dakota, Wisconsin and the United States Department of Agriculture co· I operating.

EC 69-1833 Extension Service University of Nebraska College of Agriculture And U.S. Department of Agriculture Cooperating E. F. Frolik, Dean; J. L. Adams, Director KEY TO DISEASES Symptoms Diseases Page

Irregular pattern of dead grass ... .Melting-out, Dying-out, Fading-out ...... 4

Round pattern of dead grass Patches from I inch to 3 feet in diameter ..... Brown patch ...... 7 Patches 1-4 inches in diameter .. . .. Dollar spot ...... 8 Dog injury ...... ,...... 17 Scattered light green patches ...... Fursarium blight ...... 9 Dead patches often following melting snow ...... Snow mold ...... 10

Surface of grass blades become powdery Reddish-brown to orange...... Rust ...... 11 Milky-white...... Powdery mildew ...... 11 Bluish-gray to black ...... Slime molds ...... 13 Black powder in stripes ...... Stripe and flag smut...... 12 Seedlings wilt and die (thin stand) ...... Damping-off, seed rot...... 15 Toadstools, mushrooms, or puffballs in the lawn...... Toadstools, mushrooms, puffballs ...... 13

Rings or arcs in· lawn; toadstools occasionally appear in the ring...... Fairy ring ...... 14 Other causes of poor turf...... Nematodes ...... 16 Insect injury ...... 16 Chemical burn ...... 16 Chlorosis or yellowing ...... 16 Buried debris . 17 Compacted areas ..... 17 Algae, green scum .... 17 Moss ...... 17

Pictures· on pages 4, 8,, II, 12, 13 and 15 used by permission of the Government Printing Office, United States Department of Agriculture. Picture on page 7, courtesy of The Morton Chemical Co. Pictures on pages 10 and 14, courtesy of Mallinckrodt Chemical Co. Picture on page 12 , courtesy of The Upjohn Chemical Co. Cover photo courtesy Better Lawn Institute. Issued June 1961, 67 ,000 Reprinted April 1962, 36,500 Revised June 1963, 51,000 Reprinted June 1964, 23,000 Revised May 1966, 83,000 Reprinted April 1968, 20,000 Revised September 1969, 36,000

2 LAWN DISEASES IN THE MIDWEST by J. L. Weihing, M. C. Shurtleff and R. E. Partykal INTRODUCTION ture is virtually impossible to con­ The amount of time and money trol, diseases may be started easily spent on lawns each year is stagger­ by too frequent watering during dry ing. In the Midwest alone there is summers. probably more than a billion dollar 3. The more often grass is wet and investment in lawns and a likely the longer it remains wet the greater 300-500 million dollars spent annu­ will be the chance of a disease prob­ ally for maintenance. Lawns are big lem. During dry periods, enough business and compare in economic water should be applied at one time importance with our major Midwest to provide adequate moisture for a field crops. week. This means the soil should be wet at least six inches clown after PREVENTIVE DISEASE CONTROL watering. The home owner is as proud of a 4. Practically all parasitic fungi of beautiful lawn as he is of a new car­ grasses can become established in the pet. After his friends and neighbors clamp mulch from clippings. Here have heaped upon him praise and they flourish and attack healthy grass admiration for his skill in growing growing through the mulch. To such a lawn, disease may suddenly guard against this, do not allow clip­ devastate large areas. This can be pings to accumulate more than yt most discouraging. inch deep. There is no secret formula for 5. Do not clip upright grasses such growing a good lawn. Lawn grasses as Kentucky bluegrass (or fescues) are simply living organisms that too closely-clipping to 2" is recom­ need sunlight, moisture, and nutri­ mended. Creeping gras ~ ~s such as ents the same as do all plants. Dis­ bentgrass and zoysia may be clipped eases occur in all plants. Following Y2 inch or less. are some facts about diseases and 6. Mow grass frequently, so that general cultural practices which will no more than one-third of the leaf help prevent them. surface is removed at one time. I. Fungi cause most of the serious 7. Areas about the lawn where air diseases in lawns. These organisms movement is restricted can be prob­ usually produce seeds (technically lem spots. Thinning or removal of called spores) that are spread by surrounding shrubs and trees allows wind, water, mowers, infected grass sunlight to penetrate and increases clippings and numerous other ways. air flow. This speeds drying of the 2. These fungus "seeds" need grass and aids in disease control. moisture and proper air temperature 8. Any grass disease may spread before they can cause infection. Dis­ and build up rapidly in a pure stand eases of lawns are, therefore, most because every plant is susceptible. common and harmful during wet, The chance for a disease to spread humid seasons. Although tempera- and build up is restricted in lawns

1 John L. Weilting is Extension Plant Pathologist, Unive1·sity of Neb1·aska; Malcolm C. Shurtleff is Extension Plant Pathologist, Unive1·sity of Illinois; Robert E. Partyka is Extension Plant Pathologist, Ohio State University. 3 containing a mixture of grass varie­ ties or species. One should be aware of the destructive diseases if he wishes to have a pure single species and to adjust his lawn care opera­ tions to perform control measures regularly.

MELTING-OUT {FADE-OUT, DYING-OUT) Symptoms A variety of symptoms are pro­ duced by this disease. Thinning out of grass in scattered areas of the lawn is one sign of melting-out. A general brownish undercast caused Figure 2. Typical lea£ spot symptom caused by dead grass leaves accompanies the by melting-out disease on bluegrass. general thinning out. As the disease from leaf sheath to leaf sheath until progresses, large irregular areas of a ~l above-ground plant parts are the l~wn are killed (Figure I). In k1llecl. The disease then may move some mstances the entire lawn is lost. clown into the crown and rhizomes Examination reveals a spotting of killing the entire plant. ' the leaves. The spots are usually In hot weather, and particularly brown or purple, or brown with a on Kentucky bluegrass, the disease purple border. They may be round may cause a sudden dying-out of or oblong and parallel to the leaf large, irregularly shaped areas. There blade (Figure 2). may be no visible symptoms on the The leaf spot stage of the disease commonly does not cause extreme foliage of dead plants and they ap­ pear to have died from drought. damage to the lawn. The more S?metimes this disease causes yel­ severe injury results when the leaf lowmg of the leaves, resembling ~h~ath area in the crown of the plant symptoms of low nitrogen or iron JS mfected. An infected leaf sheath deficiency. Later, much or all of the will turn brown and die-resulting in death of the leaf blade. Under moist affected areas may die out. The inter­ nal tissues of the crowns and roots conditions the disease progresses of the affected plants in these areas are brown and rotten. Procedure for diagnosing melting­ out disease: I. Check the leaf blades for leaf spots. This symptom may not be apparent during midsummer but is common in the spring and fall. 2. Check the leaf sheath for brown discoloration. 3. Where the lawn is yellowing Figure I. The lawn on the left is dying and dying, check the crowns and from melting-out disease. At right is healthy roots for a brown rotting of these lawn. parts. 4 INI=ECTION B Y AIRBOI?N E SPORES RESULT IN LEAF SPOT !N .t:ECTION.

4/P~ t S PORES ARt: PllOOUCEO IN TI-lE DEBRI S W/-110 1 LAWN M OWED '-I INFECTED ARE CA RR/EO BY AIR CUR­ LEAVE S FAll. ONTO M ULOt. REN TS ro OTJ..IER AREAS OR PRODUCE ~URTI-IER t I N~lCTION IN THIS DISEASE ORGANISM VIC INITY. REM AINS ALlY£ IN THE MULCH WIICRE !AI THE PRESEN CE OF M 0 /5- TURE I T GROWS WELL €;- SUB SEQUENTLY A T­ TACKS TI-lE LEA l= SHEATH / ~ CROWN OF PLANTS. INFE C. TED \..E AF S ~E ATI-~ TI-lE. FUNGUS l.IVE S O VER WINT€R IN THE INFECTED DEBRIS f:( INFECTED TI SSU ES OF liVING Pl A NTS.

Figure 3. This drawing shows the life cycle of the fungi that cause melting-{)ut (Fade-out, Dying-{)ut) diseases.

4. Where sudden dying-out of on feet, etc. Here they may cause areas of various sizes occurs in mid­ infection if there is free moisture on summer, first check for sod webworm the surface of the plants. Excessive or grub damage. Grubs are usually moisture and favorable temperatures found about one inch below the sur­ during the next several clays will face of the sod where they have cut allow the organisms to develop rap­ off the grass roots. Sod webworm idly, resulting in death of many commonly chews the grass off at the plants. soil surface. If grubs and sod web­ worm are absent and fertilizer and Control moisture are adequate, but there are Resistant varieties. There are ma­ no distinctive foliage symptoms, then jor differences among varieties of the grass may have died as a result Kentucky bluegrass in resistance to of root infection by one of the melt­ the melting-out fungi. For example, ing-out organisms. Merion bluegrass is resistant to H . vagans and H. dictyoides but suscep­ Cause tible to H. sorohinianum. This disease is caused by several Watering. Do not keep the grass species of H elminthosporium. All of continuously wet or allow it to be­ these fungi have essentially the same come excessively dry. Usually a lawn life cycle (Figure 3). need not be watered more than once The organisms produce spores a week if the soil is soaked to a depth (seeds). These spores can be blown of 6 inches or more at each irriga­ around by the wind or may be car­ tion. During midsummer if the grass ried to other areas of the lawn by is allowed to become so dry that it mowers, flowing or splashing water, begins to go dormant, or becomes 5 dormant, and then is watered heav­ control because the fungus is most ily, melting-out disease may occur. likely established in the crowns, The crown and root rot phase of this roots and rhizomes. These tissues can disease occurs more readily whenever not be reached satisfactorily by most the plants are suppressed in vigor by fungicides. Proper spring spraying one cause or another. Therefore, it may reduce the amount of the dis­ is important to keep the grass in ease so that the lawn will progress good vigor, particularly during hot satisfactorily throughout the rest of weather. the growing season. Removal of lawn clippings. A Best results are obtained when the dense mulch is ideal for the develop­ chemicals are applied as a drench at ment of melting-out organisms. Clip­ the recommended ounces per I ,000 pings should be removed from lawns. sq. ft. in 5-15 gallons of water. A Thatch may continue to build up hose-end sprayer which will handle even though clippings are removed wettable powder fungicides is satis­ because of the dying-off of the old factory for making applications. A foliage of the lower part of the plant. commercial wetting agent or If it accumulates above Y2 inch, the spreader-sticker should be put into lawn should be power raked either the spray solution to get the neces­ in early spring or early fall. Aerifica­ sary coverage. Ask your pesticide tion will help by bringing up soil dealer about them. Where commer­ which becomes mixed in the thatch cial wetting agents are not obtain­ thereby increasing the rapidity of its able you could use a common decay. household detergent at the rate of Spray program. A severe outbreak I teaspoonful per gallon of water. of melting-out is difficult to stop. Sporulation (fungus seed produc­ There is such a large amount of tion) takes place in the thatch. A the disease organism that protective wetting agent will result in better measures listed above will not reduce coverage of the plants for protection sufficiently the quantity of the para­ and a soaking of the thatch to in­ site to stop its development. In such hibit the disease organism. Excellent cases it will be necessary to spray. distribution and coverage is the key Good protection against melting­ to control. out is attained by spraying every I There are a number of chemicals or 2 weeks from the time the grass that, when properly used, give satis­ greens in the spring until late fall. factory control of melting-out. New However, such a spray program is and more effective chemicals are expensive and perhaps beyond the being developed. Check with your finances or available time of the county Extension agent or equiv­ average lawn owner. alent, each spring to see if any new When only a few sprayings can be chemicals or practices are recom­ made it is best they be applied in the mended. Following is a list of sug­ spring. Make the first one shortly gested fungicides: after the grass greens up, a second Phaltan-A wettable powder which one three weeks to a month later is reported to be giving excellent and a third one a month after the control of melting-out. It is used as second one. an ornamental, fruit and vegetable If you wait until midsummer to fungicide. spray, the disease will likely have Folpet-Same as Phaltan. increased and caused extensive dam­ Daconil 2787-A relatively new age. At this time it is hard to gain fungicide useful in the control of sev-

6 eral lawn diseases. It is a wettable powder. Follow the manufacturer's directions. Difolatan-A new wettable powder which has given excellent control of several lawn diseases. Follow manu­ facturer's directions. Fore-The active ingredient is the same as in Dithane M-45, but the product is designed for use on turfs. It is a wettable powder. Follow the manufacturer's directions. Dithane M-45-Same as Fore. Manzate 200-The active ingred­ Fig·ure 4. Brown patch disease in bentgrass ient is the same as Fore. go)( green. Ortho Lawn and Turf Fungicide­ This is a broad spectrum turf fungi­ faces are covered with free moisture cide which contains Phaltan (Folpet), for long periods. thiram and cadmium for the control of many lawn diseases. Cause Tersan OM-A wettable powder, Brown patch is caused by the com­ broad spectrum fungicide designed mon soil-borne fungus, Rhizoctonia for turf diseases. so/ani. T his organism is present in Actidione-thiram- A fungicide de­ most fertile soils. Virtually all lawn signed for the control of a number grasses grown in the Midwest are of lawn diseases. attacked. Bentgrasses are more seri­ ously injured than the coarser blue­ BROWN PATCH, grasses and red fescues. Colonial RHIZOCTONIA DISEASE bents are more susceptible than Symptoms creeping bents. This disease appears as somewhat T he fungus parasitizes the grass circular brown patches, up to several blades, leaf sheath, stems, crowns and feet in diameter (Figure 4). Grass even the roots, causing their death. leaves are first watersoaked and dark, T he fungus is believed to over­ but soon dry, wither and turn light winter principally as small, hard brown in color. On close-clipped brown to black bodies (sclerotia) bentgrass a dark, grayish-black ring which measure about 1 ho of an inch of wilting grass borders the diseased long. These are formed on under­ areas. This ring is noticeable in the ground parts of infected plants or morning but disappears when the in the top Y2 inch of soil. Sclerotia grass dries. Turf generally recovers are extremely resistant to heat, cold, from brown patch in two or three drought and chemicals. During moist weeks. '!\Then severe, however, the periods, when the soil temperature roots and crowns may not, especially is above 60 ° F., the sclerotia send out in southern states. Such turf is killed microscopic filaments which pene­ or thinned out in large areas. Brown trate and infect grass plants. patch occurs in hot, humid, summer For the brown patch fungus to weather when night temperatures attack grass leaves, four conditions are above 70° F., and when leaf sur- must be fulfilled: 7 l. The presence of the active fun­ DOLLAR SPOT, gus in the soil or turf mat. 2. A dense growth of susceptible SMALL BROWN PATCH grass. Symptoms 3. A prolonged dew or film of This disease appears as round, moisture on the foliage. brown or bleached spots, the size of 4. The maintenance of a tempera­ a silver dollar, or somewhat larger ture of 70° to 95° F. for at least (Figure 5). On bluegrass and fescues several hours. the spots may reach four to six inches If one of these conditions is lack­ in diameter. If left unchecked, the ing, brown patch will not be severe. spots may merge forming large, ir­ The brown patch fungus grows regular, straw-colored, sunken areas. out radially through the soil from When dollar spot is active a white, germinating sclerotia-hence the cir­ cobwebby growth can be seen on the cular spots. Under hot and humid grass leaves when clew is still present. conditions the lower grass leaves Injured turf recovers quickly if touching the soil or turf mat are treated promptly. If left untreated attacked. Infection then progresses it may take weeks or months for new up the plant and spreads to adjacent grass to fill in the sunken dead areas. grass blades in the "dew" or exuded water on the leaf tips. Cause Sclerotia may germinate and cause The white, cobwebby growth on infection an indefinite number of the grass foliage is the dollar spot times (30 or more) and survive in fungus, Sclerotinia homeocarpa. Dol­ soil for a number of years. The fun­ lar spot may occur regardless of man­ gus is also capable of surviving up to agement or soil fertility, but damage four months in dried grass clippings. is usually most severe if there is a deficiency or great excess of nitrogen. Control Dollar spot is most active during moist periods of warm (60-86° F.) Avoid overwatering and frequent clays and cool nights in spring, early late afternoon or evening sprinkling. summer and fall. Water early in the day so that the grass leaves will be dry before eve­ ning. A void overfeeding during sum­ mer months with a quickly available, high-nitrogen fertilizer. Less brown patch occurs when the available ni­ trogen supply in the soil is low and phosphorus and potassium levels are high. Prune dense trees and shrubs to let in sunlight, increase air circu­ lation and promote faster drying. If possible, remove the clippings. Spray weekly in hot, humid weather, using Benlate, Daconil 2787, Ortho Lawn and Turf Fungicide, Dyrene, Difola­ tan or Tersan OM. Follow the manu­ facturer's directions. Apply sprays in the evening if the temperature is Figure 5. Typical dollar spot leaf lesions 80° F. or above. on Kentucky bluegrass. 8 All lawn grasses grown in humid areas of the north central states are attacked. Bentgrasses, especially cer­ tain strains of creeping bent, are most susceptible. Control Follow the same cultural practices as for Brown Patch. Maintain ade­ quate to high fertility by following the recommended lawn feeding pro­ Figure 6. Fusarium blight. gram for your area. Spray during the spring months and again in late sum­ will be scattered throughout the mer and fall using Benlate, Dyrene, lawn. Centers of green, apparently Ortho Lawn and Turf Fungicide, healthy grass, may occur in patches Actidione-Thiram, Kromad, Tersan of dead grass giving a frog-eye pat­ OM, Daconil 2787, Thimer or cad­ tern appearance to the area. mium compounds. (In some regions The frog-eye pattern is a key diag­ the dollar spot organism has devel­ nostic feature of the disease. When oped resistance to cadmium fungi­ ideal conditions for disease develop­ cides. Follow manufacturer's direc­ ment exist for an extended period of tions. Start applications when disease time, these affected areas overlap is first evident. each other. The result is a com­ pletely blighted area. In some cases FUSARIUM BLIGHT pink mycelial growth can be found in the crown area of the plants. This turf disease was recently iso­ lated and identified by plant path­ Cause ologists at Pennsylvania State Fusarium blight is caused by two University. It is becoming one of the fungi, Fusm·ium roseum f. Sp. cere­ most troublesome diseases in the east­ alis 'Culmorum' and F. tricinctum f. ern part of the United States on sp. poae. F. roseum appears to be the Merion bluegrass. Other grasses also more important fungus at the pres­ appear to be susceptible to the ent time. Fusarium roseum is widely disease. distributed throughout the U.S. but the disease is found only in limited Symptoms areas at present. The first symptoms of affected turf Dry, warm-to-hot conditions are grass appear as scattered light green required by these fungi to grow ac­ patches varying from 2 to 6 inches in tively on grass. Temperature ranges diameter (Figure 6). During favor­ from 75 to 95° F. or above with high able conditions for disease develop­ humidity at the grass level favors dis­ ment the color of these patches ease development. Disease severity changes in a 36-48 hour period to appears to be directly proportional dull reddish-brown, then to tan, and to the intensity and duration of sun­ finally a light straw color. The light. Diseased turf has not been ob­ patches may be elongate streaks, cres­ served in heavily shaded 'areas. cents or circular patches. In the final stages of the disease Control distinct streaks and uniformly blight­ I. Maintain grass in vigorous eel circular patches of diseasesd grass growing condition but avoid ex.ces- 9 sive nitrogen fertility during those SNOW MOLD times of the year when attack may be expected such as hot periods of Symptoms the summer. This disease appears as a more or 2. Keep thatch to a mm1mum as less circular, dead, bleached area this provides an ideal area for the from one inch to several feet in di­ fungus to overwinter and multiply. ameter. Several spots may run to­ 3. Bentgrass, fescue, ryegrass and gether forming large, irregular areas. bluegrass are susceptible to this dis­ Affected grass may be first covered ease but Merion bluegrass appears to by a dense, whitish-pink or dirty be the most susceptible at the present gray to almost black mold growth. time. The disease is usually found in win­ 4. A protective spray program ter or early spring in wet, shaded should be used to keep this disease to areas or where snow is slow to melt a minimum if it is or has been pr ~s­ (Figure 7). A crust-like mat of light ent in a lawn . Once the disease be­ brown foliage may form where the comes well-established during the grass has been left long. Roots and summer it may be difficult to control. stems may be rotted over a wide Given rates should be mixed with range of temperatures (28-65 ° F.). All 10 gallons of water and applied to lawn grasses are susceptible. Bent­ 1,000 sq. ft. of turf area. Use at least grasses are more severely attacked I 00 pounds per sq. in. of pressure to than coarser lawn grasses. obtain even distribution. Apply at 7-10 day intervals in April through Cause September for bents and fescues and Various fungi. Pink snow mold is .July through August for bluegrasses. caused by Fusarium nivale (Calonec­ Fore-4-6 oz. (14-2 1 Tbs.) t?·ia), while grey snow mold is caused Tersan OM1-4-6 oz. by Typhula spp. The latter fungi produce clark mold growth on affect­ ' This material is poisonous and should not be used by homeowners unless all pre­ ed areas. In some northern areas, cautions on the label are followed. where summers are cool and moist,

Figure 7. Snow mold injury (next to oak leaf) as snow melts. This growth on the grass is a fungus. When freshly uncovered from the snow, it is whitish but soon becomes a dirty gray to almost black.

10 species of Fusarium are active throughout the summer. Infection and injury may take place both under the snow and as the snow is melting. Frequently, snow mold damage will conform to foot prints, ski tracks, etc., because compaction of snow favors the dis­ ease. Injury ceases when the grass surface dries out. Control In northern states do not fertilize after September 15. Follow cultural recommendations for your area. Lawns should not go into the winter growing at a fast rate. Keep the Figure 8. Rust lesions on bluegrass. The lawn cut to recommended height lesions contain reddish dust-lil

ll Figure 9. The white substance on the leaves is the powdery mildew fungus.

POWDERY MILDEW Symptoms A turf heavily infected with mil­ dew looks as if it has been dusted with flour or lime. Examination of the grass blades reveals a white, powdery-like growth (Figure 9). In­ Figure 10. Leaves o( a Kentucky bluegrass plant curled and sluedded by stripe smut fected leaves usually yellow and infection. wither. New plantings and estab­ lished turf may be killed if mildew ~s severe. Disease attacks occur chiefly STRIPE AND FLAG SMUT rn the fall and spring when nights Symptoms are cool. Stripe and flag smuts ~re more Cause prevalent during the spring or fall, Mildew is caused by a fungus as they are favored by cool tempera­ (E1ysiphe graminis) which is con­ tures. Infected plants are usually first fined to the surface of the leaves. It noticeable singly or in patches from sends sucker-like structures into the a few inches to a foot or more in di­ leaf cells from which it obtains its ameter. Infected plants are often pale nourishment. The aerial portion of green to slightly yellowed and stunt­ the fungus produces thousands of ed. Observing the leaf blades more "seeds" which are distributed by air closely, they are found to be curled currents and result in new infections. and to have black stripes. A black, Mildew is most severe in shaded and soot-like dust rubs off from these protected areas. stripes. vVhen the stripes are first developing, they are gray and may Control or may not be continuous along the This disease can be checked by lea.£ blade. It is after these gray thorough application of Karathane leswns rupture that they turn black. (Mildex), an Actidione product or The leaf then twists, curls and shreds from the tip downward (Figure 10). ~usting sulfur. Make two applica­ tiOns about 10 days apart. Keep the lawn vigorous by fertilizing and Cause maintaining adequate moisture in Stripe and Flag smuts are caused the s?il. If possible, reduce shade by by, respectively, Ustilago striifOTmis prumng dense trees and shrubs. and Urocystis agropyri. The soot-like 12 ering or shading otherwise healthy surfaces. The masses dry to form bluish-gray, gray, black or white powdery structures (Figure 11). When crushed between the fingers, they disintegrate into a powdery mass that easily rubs free from the grass blade.

Cause Slime molds are not parasites. T hey are soil inhabiting orgamsms (Mucilago spongiosa, Physarum cine- Figure I I. The whitish growth on the grass blades is slime mold. 1·ewn, etc.) which feed on decaying organic material in the soil. In 1m­ rna terial is actually a mass of smut mid weather a slime mold grows out spores. These spores infest the soil of the soil onto whatever is available where they are capable of germinat­ for support and produces its spore ing and producing an infection masses. A well-watered, well-fertilized thread which can invade grass seed­ lawn provides an ideal environment. lings or young tillers. The fungus Control will grow systemically in the plant If left alone, the slime mold soon tissues and will remain within the disappears. However, since it is un­ plant until it dies. Infected plants sightly a home owner may wish to usually die during hot dry weatiier. remove it. This can be clone by a Control forceful spray from a garden hose or with a garden rake. Fungicides ap­ Certain varieties of Kentucky blue­ plied to control Melting-out, Brown grass and creeping bentgrass are Patch or other diseases should keep highly resistant or immune to stripe slime molds in check. and flag smuts; other varieties are very susceptible. Benornyl (Benlate) has eliminated smut fungi within TOADSTOOLS, MUSHROOMS, both bentgrass and bluegrass plants PUFFBALLS when applied as a soil drench in sev­ eral applications at 2-4 week inter­ Symptoms vals. The manufacturer's directions Everyone has seen toadstools, should be carefully followed. mushrooms and puffballs of various sorts (Figure 12). Sometimes they are SLIME MOLDS quite an annoyance. Some are foul­ smelling; some are poisonous and a Symptoms menace to children and pets. These normally harmless pests fre­ quently cause considerable alarm. Cause They commonly appear in the Toadstools, mushrooms and puff­ spring, but may occur during mid­ balls are fruiting structures of vari­ summer or fa ll following heavy rains ous kinds of fungi. These fungi grow or watering. Small white, gray or yel­ on rotting wood or decaying organic low slimy masses grow over the grass material in the soil. They <~re com­ in round or irregular patches srnoth- monly found in areas of buried tree 13 stumps, dead roots, logs, boards and fAIRY RING a thick thatch following heavy rains or watering. Symptoms Fairy Ring disease causes a circu­ Control lar ring of fast-growing, clark green These fungi are difficult to control grass ~ften surrounding a ring of until all of the wood or other organic thin or dead grass (Figure 13). Some­ matter upon which they are feeding times the ring is not complete and has been completely consumed. Tem­ gives the appearance of an arc or porary control may be obtained by horseshoe. The rings vary in size applying Panogen Turf Spray, from a few inches in diameter to phenyl mercury, Thimer or Tersan many feet. The strip of thin or dead OM within and around the sur­ grass varies from three to six inches rounding area. (Caution: Mercuries in width. After rains or watering are highly toxic and care should be many mushrooms or toadstools may taken not to get them on the skin. appear in the area of clark green \!\Tear rubber gloves and clothing as grass. Occasionally the symptoms protection.) However, after the chem­ may appear as "dry patches" in lawns ical has been clissi patecl, the toad­ instead of a ring. stools or mushrooms usually come back. Treatment may be necessary at Cause monthly intervals. Follow the direc­ Fairy ring is caused by several soil­ tions given under Fairy Ring. In inhabiting mushroom (toadstool) some cases it may be practical to dig types of fungi (Marasmius oreades, up the pieces of buried wood. It is PsnJ/£ota (Agaricus) campestris, Le­ usually best to let them go ahead and piota morgani etc.) which grow very complete the decay of the material, extensively in the area of the ring. after which they will disappear. Growth starts with a germinating

Figure 12. Toadstools growing in a lawn. 14 Make holes Y2 to I inch in diameter, 4 to 5 inches apart and 6 to 8 inches deep in the ring of stimulated grass and about 6 inches outside the ring. Fill the holes within one inch of the soil surface with a solution con­ taining a mercurial fungicide such as a mixture of calomel 2 parts and cor­ rosive sublimate I part mixed in water at a rate of 2 ounces (IY2 table­ spoons) per gallon; phenyl mercury compounds such as PMAS, I fluid Figure 13. A large fairy ring with toadstools ounce, or P uraturf No. I 0, 2 fluid (mushrooms) growing at the outer edge. ounces per 5 gallons of water; or Panogen Turf Spray as recom­ "seed" at a central point and fila­ mended on the container. (Caution: ments of the fungus grow outward mercuries are highly toxic and care equally in all directions. Outward should be taken not to get them on spread may occur at the rate of a few the skin. Wear rubber gloves and inches to two feet or more per year. adequate clothing as protection.) Use The part of the fungus on the inner a battery bulb or watering can with side of the circle dies off as the fun­ spout in filling the holes to avoid gtiS grows outward . T he darker green spilling the solution on the grass. grass is ca used by microorganisms in Wash off the grass if any is spilled. the soil breaking clown organic mat­ Another method of control in­ ter, subsequently resulting in greater volves removal of the sod and steril­ nitrogen availability. ization of soil underneath using a soil fumigant (e.g., methyl br:omide, Control chloropicrin, Vapam, VPM Soil Fu­ The most sa tisfactory method of migant, etc.). The manufacturer's di­ handling this situation is to "mask" rections must be followed carefully. the rings by pumping large quanti­ ties of water 12-24 inches deep into DAMPING-OFF, SEED ROT the soil within the ring of dead grass using a "root feeder" attached to a Symptoms garden hose Repeat when rings Seeds rot in the soil. The grass appear. stand is thin and sickly in irregular Fairy ring is difficult to control patches . Seedlings are stunted, water­ beca use the soil in the area in which soa keel, a ncl turn yellow to brown. the fungus is present becomes imper­ T hey may wilt and collapse. Surviv­ vious to movement of water. The ing plants are weakened. Stand is fungus can be killed by the use of slow to fill in. Affected areas are mercury fungicides, but the main often heavily invaded by weeds. problem is getting the fungicide in co ntact with the organism. Control Cause will not be satisfactory unless this Numerous soil-borne fungi (espe­ is accomplished. cially Pythium and Rhizoctonia spp.) Prior to making a fungicide appli­ may cause this disease. Attacks are ca tion, break up or perforate the most severe during warm weather fairy ring soil with a spading fork (May-June) on heavy, moist or water­ or some similar aerifying instrument. logged soils. 15 Control face. Nematodes may cause wounds Plant good quality seed in a well­ through which disease-producing mi­ prepared, fertile seedbed. Provide for croorganisms may enter. Most nema­ good soil drainage when establishing tode types are harmless, feeding a new lawn. Fill in low spots where upon decomposing organic material water may stand. Treat seed before and other soil organisms. A few are planting by dusting thoroughly with ~e~eftcial to man since they are para­ srtlc on plant-feeding types. thiram or ca ptan seed treatment (Yz teaspoonful per pound of seed). Control Avoid overwatering after planting. Keep grass growing vigorously by If possible, seed in late summer or watering, fertilizing and following early fall. The next best time is early cultural practices outlined above. If spring. After a planting apply a severe, apply Nemagon or Fuma­ spray of Kromad, captan, Dexon, zone, following the manufacturer's thiram, maneb, or zineb. Use 4 directions. ounces of chemical in 3 gallons of water to cover 1,000 square feet. OTHER CAUSES OF POOR TURF NEMATODES Insect Injury Symptoms Numerous insects, including grubs, Turf lacks vigor, often appears off­ ants, webworms, chinch bugs, leaf­ color, yellow, bunchy and stunted. hoppers and others may damage turf. Grass blades dying back from the Insect injury may closely resemble tips may be interspersed with appar­ one or more lawn diseases. If you ently healthy leaves. Injured turf suspect a lawn insect problem con­ may later thin out, wilt and die out tact your county Extension office or in irregular areas. The severity of the Extension entomologist at your symptoms varies with the quantity land-grant university. of plant parasitic nematodes feeding on and in the roots. Chemical Burn Nematode injury is often con­ Agricultural chemicals (e .g. ferti­ fused with fertilizer burn, a soil nu­ lizers, pesticides, hydrated spray lime) trient deficiency, poor soil aeration, m~y injure grass if improperly ap­ drought, insects, and other types of plied. Burned areas may occur in injury. Nematode-injured grass does spots or streaks, or the entire lawn not respond normally to water and may be "scorched." Prevent injury fertilizer. Damaged roots may be by following the directions printed swollen, shallow, "stubby" and dark on the package label. Apply ferti­ in color. The presence of plant para­ lizers evenly in recommended sitic nematodes can only be identi· amounts, when the grass is dry. Then fted by taking plugs of suspected turf water immediately. The use of a and having them examined by a lawn spreader is highly recommend­ competent nematologist. ed. Ground agricultural limestone is safer to use on lawns than hydrated Cause lime. Nematodes are microscopic, slen­ der roundworms (sometimes called Chlorosis, Yellowing eelworms or nemas). They live in the Areas or all of the turf may be­ soil where they penetrate into grass come yellowed and stunted. Chloro­ roots or suck sap from the root sur- sis (yellowing) is usually caused by 16 nitrogen or iron deficiency. Most aerifying the soil using an aerifier or lawn fertilizers contain- nitrogen. If installing drainage tile for seriously a fertility program is carried out water-logged soils. This allows water this element is probably being ap­ and air to penetrate into the soil. If plied in sufficient amounts. How­ necessary, fertilize and reseed. Re­ ever, if the lawn continues to remain duce foot traffic on lawn by putting yellow after nitrogen application the in a walk or patio or erect a fence cause is likely to be iron deficiency. or plant a shrub. T his is most likely if the soil is either highly acid or highly alkaline. Algae, Green Scum Control: Apply 2 or 3 pounds of A green to blackish scum may iron sulfate (sold as "Copperas" or form on bare soil or thinned turf. "Sulfasoil") in 5 to 10 gallons of This is most common in low, wet, water per 1,000 square feet. Repeat shaded or heavily used and com­ the treatment as necessary to main­ pacted areas. The mass of algae (mi­ tain normal green turf color. Take nute plants) dries to form a thin, care to avoid spray drift because iron black crust which later cracks and sulfate leaves a brown stain. Some peels. lawn fungicides (e.g., Kromad, Acti­ Control: Perform the same cul­ dione-Ferrated, etc.) already have tural practices as for Brown Patch iron sulfate in the spray mixture. and Compacted Areas. Where neces­ Iron chelate materials (e.g., Versonol, sary, apply a spray of Fore, maneb, Sequestrene) also correct iron defi­ Daconil 2787 or copper sulfate, 1-2 ciency. When starting a new lawn ounces in 3 to 5 gallons of water, to have the soil tested before seeding. 1,000 square feet of lawn. This can be done, usually for a small service charge, by your state uni­ Moss versity or by a private soil testing Moss occurs in lawn areas low in laboratory. The pH of the soil fertility, with poor drainage, high (sweetness or sourness) should be soil acidity, too much shade, watered close to neutral (pH 6.5 to 7 .0). If improperly, heavily compacted or a the pH is far outside this range combination of these factors. (below pH 6.0 and above 7.3) check Control: Remove moss by hand with your county Extension office on what and how to bring the soil raking. Correct the unfavorable con­ dition by following the cultural prac­ within the desired range. tices as for Compacted Areas and Buried Debris Algae. Have a soil test made and A thin layer of soil over buried follow the instructions given in the rocks, lumber, bricks, plaster, con­ report. Follow recommendations on crete, etc., dries out rapidly in hot maintaining turf suggested on page 3. summer weather and may resemble disease. Control by digging up suspi­ Dog Injury cious areas and removing the cause. Injury from dog urine, principally female, may resemble brown patch. Compacted Areas Affected areas are often more or less Thin turf or bare spots appear in round and commonly are several heavily used areas. Waterlogged soils inches or larger in diameter. Injured become packed and later bake hard grass turns brown or straw-colored if walked on constantly. Correct by and usually dies.

17 Summary of Diseases Controlled by Various Fungicides

Season Disease Fungicides Ounces per Remarks 1000 sq. ft.

Spring Snow mold Tersan OM 6- 8 Most materials may be applied dry, as sprays, Ortho Lawn and Turf Fungicides 4-6 or mixed with a granular fertilizer_ Apply to Dyrene 6-8 problem lawn or fine turf areas following first Thimer 4-6 heavy snow or when cold, drizzly weather is Difolatan (Folcid) 4 forecast in late fall. Reapply 1-3 times during Daconil 2787 2-4 winter or early spring as snow melts. Follow Phaltan 2-4 manufacturer's directions carefully. Follow rec­ Cadmium compounds See label ommended fertilizer program but avoid appli­ cations following September 15, particularly Nitrogen. Use lime only when needed.

Powdery mildew Karathane WD Y2 Two to three applications are needed 7- 10 days Actidione-Thiram 2-4 apart in spring and fall when days are warm Sulfur and nights cool. Most serious in shady, damp locations. Fall established, effected turf may -CXl winter-kill. Spring or Melting-out, Actidione-Thiram 2-4 Where it is necessary ·to maintain quality turf Summer Fading-out, Difolatan 4 such as in golf courses, fungicides are best ap­ Dying-out Folpet 2-4 plied on a regular, protective schedule. If disease Ortho Lawn and Turf Fungicide 4-6 usually occurs during cool, wet, weather, begin Dithane M -45 2-4 applications in early spring when first leaves are Tersan OM 6-8 formed. Continue at 1- 2 week intervals until Daconil 2787 2-4 warm, dry weather comes. If disease usually Phaltan 2-4 occurs during hot weather, begin treatment in Fore 2-4 mid-May in southern midwest to mid-June in Manzate 200 2-4 northern midwest.

In home lawn, the disease is usually checked by cultural practices, e.g., mowing at recommended maximum height, collecting clippings, keeping down thatch, avoiding overwatering, fertilizing following recommended program, watering sel­ dom but deeply, increasing air circulation, etc. Summary of Diseases Controlled by Various· Fungicides (Continued)

Season Disease Fungicides Ounces per Remarks 1000 sq. ft.

Summer Brown patch Ben late 2 Apply weekly in hot, moist weather. Avoid over­ Ortho Lawn and Turf Fungicide 4-6 watering (especially in the evening), frequent, Dyrene 4-8 light watering, and over-fertilizing with quickly Difolatan 4 available, high-nitrogen fertilizers. Increase air Tersan OM 6--8 movement. Remove dew on golf greens early in Daconil 2787 2-4 morning. This disease is most severe when eve­ ning temperatures remain above 70° F.

Dollar spot Cadmium compounds See label Apply in spring, early summer and fall when Kromad 3---4 temperatures averages between 60° and 80° F. Dyrene 4-8 Cadmium compounds last the longest. Use same Ortho Lawn and Turf Fungicide 4-6 cultural practices as given for melting-out and Actidione-Thiram 2-4 brown-patch diseases. :0 Benlate 2 Tersan OM 6--8 Daconil 2787 2-4 Thimer 1Y2.-4

Fusarium blight Fore 4-6 Tersan OM 4-6

Fall Rust Actidione-Thiram 2-4 This disease is rarely a problem until the rate of Zineb 2-4 growth of the grass is slowed down in the fall Maneb 2-4 due to drought, short days, and cool tempera­ Dyrene 4-8 tures. Where it is a problem, make three weekly Sulfur 6--8 applications. Tersan OM 6--8 Tersan Powdery mildew See above under Spring Read the entire pesticide label It tells you -what the chemical is -the diseases it controls -grass spedes on which to use it .:_how much to use -when to use

Apply only as directed -- controls will be more effective -chances of plant injury are reduced

Handle pesticides carefully - take proper precautions with children and I pets -avoid drift -wear protective clothing if specified -clean-up immediately after application -safely dispose of empty containers -keep and store in the original labeled con- tainers out of the reach of children and irresponsible adults