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1973 EC73-1833 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., "EC73-1833 Lawn Diseases in the Midwest" (1973). Historical Materials from University of Nebraska-Lincoln Extension. 4223. http://digitalcommons.unl.edu/extensionhist/4223

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. ~£=&.ev-t r1 i-.e Es5 E} North No. 12 MAY 3 11973 t£13 - IL../'--"~""'-1 Lawn Di

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Agricultural Extension Services of Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Ne­ braska, North Dakota, Ohio, South Dakota, Wiscon­ sin and the United States Department of Agriculture cooperating.

EC 73-1833

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 LAWN DISEASES IN THE MIDWEST Symptoms Diseases Page by Irregular patterns of dead grass ...... Helminthosporium leaf spot J. L. Weihing, M. C. Shurtleff, R. E. Partyka and and melting-out ...... ·..... 4 J. M. Vargas, Jr. 1

Round patterns of dead grass INTRODUCTION other plants. Not all law ns are affected Patches from 1 inch to 3 feet with the same disease; some areas are in diameter ...... Rhizoctonia brown patch ..... 10 more disease-prone than others. Follow­ Patches usually 1-6 inches in An attractive, beautiful, well-kept lawn is an important and valuable asset ing are some facts about disease and diameter ...... Dog injury ...... 19 general cultural practices that help pre­ Sclerotinia Dollar spot ...... 9 to the home as well as commercial and industrial complexes. vent them, reduce their effects, and fos­ Pythium blight ...... 15 ter plant recovery. The amount of time and money spent Corticium red thread ...... 16 1. Fungi and n ematodes a 1·e the Light green to straw-colored patches on lawns each year is staggering. In the Mid west alone, there is probably more cause of all serious infectious diseases often have green centers ...... Fusarium blight ...... 8 in lawns in the Midwest. The fungi usu­ Dead patches often following than a two bi llion dollar investment in lawns and an excess of one-half billion ally produce microscopic spores that are melting snow ...... ~now molds ...... 13 spread by wind, water, mowers or other dollars spent annuall y for maintenance. Lawns are big business and compare in equipment, and infected grass clipp­ mgs. Nematodes are mi croscopic worms Surface of grass blades become powdery economic importance with major Mid­ which survive in the soil or grass debris Reddish-brown to orange ...... Rust(s) ...... 11 west fie ld crops. as eggs, cysts or larvae and feed on the Milky-white ...... Powdery mildew ...... 7 T he homeowner is as proud of a roots of grass plants. Bluish-gray to black ...... S lime molds ...... 17 beautiful lawn as he is of a new carpet 2. Fungus spores need proper mois­ Black powder in stripes ...... Stripe and flag smut ...... 7 or automobil e. After frie nds a nd ture and favora bl e te mpe ratures to Seedlings wilt and die (thin stand) ...... Damping-off, seed rot ...... 16 neighbors h ave h eaped pra is e and infect. Lawn diseases are most common Mushrooms or puffballs in the lawn ...... Mushrooms, puffball s ...... 12 admit·ation for his skill in growin g such and damaging duri'ng wet, humid sea­ a lawn, disease rna y suddenly devas tate so ns, or with freque nt li ght wa terings la rge areas. This is most discouraging. Rings or arcs in lawn; mushrooms during dry periods. occasionall y appear in the rings ...... Fairy ring ...... 12 3. Water properly. The more often Other causes of poor turf ...... Septoria leaf spot or· PREVENTIVE DISEASE grass is wet and the longer it remains tip blight ...... 16 wet, the greate1· are the chances of dis­ Nematodes ...... 17 CONTROL ease problems occurring . During dry penods, e nough water should be Insect injury ...... 18 This circ ul a r is writte n for the Chemical burn ...... 18 applied at one time to provid e adequate homeowne r who desires to keep his Chlorosis or yellowing ...... 18 moisture fo1· a week. This means the soil lawn as disease-free as practi ca l. Much Buried debris ...... 19 should be wet 6 to 8 in ches deep. of the information should prove useful Compacted areas ...... 19 . 4. Remove excess thatch in early spr­ to th e professional turfgrass ma nage1·. Algae, green scum ...... 19 mg or early fa ll when one-half inch or Moss ...... 19 The re is no magic fo1·mula for pro­ more has accumulated. Use a "vertical ducin g a good lawn. Like a ll pl ants, lawn mower," "power ra ke" 01· similar equip­ Pictures on pages 4, 8, 11 , 12, 13 and 15 used by permiss ion of the Government Printing Office, United g rasses need proper amounts of light, ment. States Departmem o f Agriculture. mo1stu re, a nd nutrients, and are subject Thatch is a ti ghtly intermingled layer Picture on page 7; counesy of The Monon Che mica l Co. Pictures on pages 10 a nd 14 , courtesy of Mallinckrodt C he mi ca l Co. to severa l diseases much the same as of li ving a nd d ead stems, leaves and Picture on page 12, counesy of The Upjohn C hemica l Co. Cover pho to courtesy Bette r Law n lnstiLUte.

Issued June 1961,67,000 'John L. Weihing is Director of the University of Nebraska Scotts Bluff Station; Mal­ Re printed April 1962, 36,500 Reprinted April 1968, 20,00u ~olm C. ~hurtleff is Extension Plant Pathologist, University of Illinois; Robert E. Partyka Revised June 1963.5 1.000 Revised Septe mbe r 1969, 36,000 Re printed June 1964 , 23,000 Reprimed ~ l a y 1970,30, 100 ts Extension Plant Pathologist, Ohio State University; and joseph M. Vargas, Jr. is Assistant Revised May 1966, 83,000 Rev ised April 1973, 53,000 Professor of Plant Pathology at Michigan State University.

2 3 roots of grasses which develops between Recommendations wi ll vary with the occurs, resembling symptoms of nit­ the layer of green vegetation and the grasses grown and their use. Do not over­ rogen or iro n deficiency . Later, much soil surface. Too much thatch keeps fertilize to promote fast lush growth , o r all of the affected area may die out. water from penetrating the soil; makes especiall y in hot humid weather, or Internal tissues of the crown and root some disease problems worse; a nd earl y spring. Overfertilizing may of affected plants are dark brown and apparently prevents the grass from accentuate disease development. rotted. putting down a deep root system. 11. Coring compacted areas, using a Procedure for diagnosing melting­ Thatch is often a n ailment of "good hand corer or power machine. Coring out: lawns." Grasses differ in their inclina­ is a form of cultivating involving the use 1. Check leaf blades for les ions. This tion to develop thatch but common of a hollow tine or spoon to remove soil symptom is most common in spring a nd Kentucky bluegrass is less likely to have cores that leave a hole or cavity in the fall. a serious thatch problem tha n soil. 2. Check the leaf sheaths, crowns, bentgrass, Merion Kentucky bluegrass 12. Follow suggested insect and weed rhizomes and roots for reddish-purple or red fescue. control programs for your area a nd to brown discoloration. 5. Do not mow upright grasses, such grasses grown. 3. When sudden d yin g-out of grass as Kentucky bluegrass and fescues too 13. Do not plant grasses that are not in areas of various sizes occurs in mid­ closely-clipping to 2" or higher is adapted to your area. Be careful of seed summer, first check for sod webworm, recommended; somewhat higher in mixtures that may contai n some "weed" chinch bug, grubs or othe r insect cl am­ summer. Creeping grasses such as grasses; plant at 1·ecommended rates. Figure 2. Typical leaf spot symptom caused age. Grubs are usually found about one bentgrasses, bermudagrass, and zoysia Additional information may b e by melting-out disease on bluegrass. inch below the surface of th e sod where may be mowed to Y2 inch or less. obtained by consulting yo ur local county they have cut off the grass roots. Sod 6. Mow grass frequently, so that no Extension office or turfgrass specialist As the disease progresses , large webworms commo nl y chew the grass more than Y4 to Y:l of the leaf surface at your state land-grant unive rsity. irregular at·eas of the lawn may be killed bl ades o ff at the so il surface, while is removed at any one time. Mow the (Fig ure 1). In some instances the entire chinch bugs s uck the sap from the blades turning them ye ll ow or brown . lawn throughout the fall until the grass HELMINTHOSPORIUM lawn is lost. stops growing. Close examination of infected leaves You may have to obtain help from your 7. Lawn areas where air movement is LEAF SPOT usually reveals lesions that are usually county Extension office in identifying restricted can be problem spots. Thinn­ AND MELTING/OUT dark reddish-brown, purplish-brown, insect injury. If there are no distinctive ing or removal of surrounding shrubs chocolate-brown, o r straw-colored with foliage symptoms, and if insects are and trees allows sunlight to penetra te Symptoms a reddish-brown to purplish-black bor­ absent while fertilizer and moisture are and increases air flow. This speeds dry­ der. They are round to oblo n g and adequate, then the grass may have died ing of the grass and aids in disease con­ A variety of symptoms are produced parallel to the leaf blade. as a resu lt of root infectio n by a melting­ trol. Space landsca pe plants prope rly to by this disease, depending on the causa l T he leaf spot stage co mmonly does out fungus. allow adequate air movement a nd to fungus, the variety affected, and the not cause se rious damage to the law n avoid excessive shade. stage of disease development. Thinning (Figure 2). More severe injury results Cause o ut of grass in scattered areas of the 8. Grass diseases may build up and when the leaf sheath area in or near the Melting-out is caused b y severa l spread rapidly in pure stands of a sus­ lawn is one symptom. A general brow­ crown of the plant is infected . A dis­ species of H elminthosporium. These fungi nish or reddish color of dead grass ceptible variety because every plant is eased leaf sh eath turns reddish to all have essentia ll y the same life cycle susceptible. Disease severity is reduced accompanies the general thinning o ut. purple or brown and dies, resulting in (Fig ure 3~. in lawns containing a compatible blend death of the entit·e leaf blade. When T he organisms produce large num­ of two or more locally adapted, disease­ conditions are moist, the d isease prog­ bers of spores which are blown or resistant grass varieties or a mixture of resses from leaf sheath to leaf s heath splas hed onto leaves, whe re infection grass species. Increased awareness of until all above-ground plant parts are may occur if there is free moisture on the destructive diseases is necessary ki ll ed. T he disease then may affect the the surface of the plants. Spores may when a single variety is grown. Adjust crown, rhizomes and roots killing the be carried to other areas of the lawn by lawn care operations and perform con­ entire plant. mowers a nd other equipme nt, foot traf­ trol measures regularly. During hot weather, the disease may fic, dragging hoses, infected clippings, 9. Provide good surface and subsur­ ca use a s udden dying of large, fl owing or splashing water, etc. face drainage when establishing a new irregul arly shaped at·eas, with no visible turfgrass area. Fill in low spots where symptoms on the foliage of dead plants. Control water may stand. Figure 1. As melting-out disease prog­ T hey may appear to have d iecl fmm 10. Fertilize according to local resses, large irregular areas of the lawn may drought. Resistant varieties. There are major recommendations and a soil test. be killed. A ye ll owin g of the leaves sometimes differences among varieties of Ken-

4 5 protective fungicides must be used in graminis) which attacks the surface of the spring during the early leaf spot leaves. It sends branched, absorptive stage. Make the first appli cation shortly structures (haustoria) into the surface after the grass greens up, and repeat at cells of leaves from which it obtains two-week intervals until four or five nourishment. Later, the fungus pro·­ applications have been made. If you cluces millions of spores which are dis­ delay until melting-out symptoms tributed by air currents. New infections appear, the disease will be difficult to are rapidly produced. The fungus sur­ control. vives the winter on living or dead grass The disease will also develop in late leaves. Mildew is most severe in shaded ~ fall during periods of cool wet weather. areas. 4IJ1IIP It is advisable to apply one or two fun­ gicide appli cations during this time Control t otherwise d isease development ma y SPORES ARE PllOOUCEO IN TJ.IE DEBRIS WH/01 Keep the lawn vigorous by adequate, lAWN MOWED Ei INFECTED progress to the point where spring ARE CARRIED BY AIR CUR­ lEAVES FAI.I.. ONTO MULCII. proper fertilization and maintaining RENTS TO OTHER AREAS application will be ineffective. OR PI?OOUCE ~URTI-IER t adequate moisture in the soil. Avoid /Nt=ECTION IN THIS DISEASE ORGANISM VICINITY. REMAINS ALlY£ IN THE excess nitrogen. Mow frequently at the MULCH WJ.IERE IAI THE POWDERY MILDEW PRESENCE OF MO!S- recommended height. Increase air cir­ TUii'E tT6ROWS WElL q SUBSt.QUf.NTL Y AT­ culation and reduce shade by proper TACKS TJ..IE LEAF- SHEATH Symptoms pruning of dense trees and shrubs. / • ~CROWN Of: PLANTS. INFECTE 0 LEAF SHEATH Kentucky bluegrass varieties with fair TI-lE t=UNGUS LIVES Heavily infected leaf blades appea.r as OVER WINTER IN THE to good resistance include Warren's A- INFECTED OEBI?/5 t;­ if dusted with flour or lime. C lose INFECTEO TISSUES 20 and A-34, Anheuser Dwarf, Belturf, OF 1./VING PLANTS. examination reveals patches of a whit­ ish, powde r y-like growth on the leaf Cougar, Delta, Fylking, Newport, Nug­ Figure 3. This drawing shows the life cycle of the fungi that cause melting-out (Fade-out, surface (Figure 4). Infected leaves often gett, Pennstar, Prato, and Soclco. Going-out) diseases. turn ye ll ow and wither. New plantings This disease can be checked by may be killed when mildew is severe. thomugh application of a fungicide. tucky bluegrass in resistance to the vari­ il y whenever grass vigor is suppressed. The disease is most severe on Kentucky Consult your state recommendations ous H elminthosporium species. For exam­ It is important to keep the grass in good bluegrass grown in the shade. Estab­ included in this circular. Make two or ple, Met·ion Kentucky bluegrass is resis­ vigor, particularly cl uring hot weather. lished plantings rna y be predisposed to three applications about 10 days apart, tant to H. vagans and H. dictyoides but A dense mat of thatch is ideal for the adverse environmental conditions. starting when mildew isfi:rst seen. susceptible to H. sorokinianwn. Also var­ development of melting-out fungi and Disease a ttacks occur chiefly in late ieties (c ultivars) of Kentucky bluegrass should be avoided. If the thatch or mat summer, fall and spring when the STRIPE OR FLAG SMUT differ in their resistance depending on accumu lates to a depth of Y2 inch or nights are damp and cool. geogra phic location . For example, more, the lawn should be power raked Windsor is H ebninthosporium resistant in in early spring or early fall. Aerification Cause Symptoms parts of Ohio but susceptible in also brings up soil which when mixed Michigan. with the thatch increases the rate of Mildew is caused by a fungus (E1ysiphe Stripe and flag smuts produce similar thatch decay. symptoms and are most noticeable dur­ Watering ing spring and fall because they are Fertilization. Follow a t·ecommenclecl favored by cool (50° to 60° F) tempera­ Avoid wettin g the grass with frequent fertilizet· pmgram; be sure to maintain tures. Infected plants usually occur li ght sprinklings, wa terlogging or the adequate levels of potassium. Avoid singly or in patches, varying from a few soil, or a ll owing the soil to become excess nitrogen as this results in soft inches to a foot or more in diameter. excessively dry. Usually a lawn need not lush grass that is very susceptible to Hel­ Infected plants are often pale green to be watered more than once every 7 to minthosporiurn disease-causing fungi. slightly yell owed and stunted. I 0 cla ys if the soi l is soaked to a depth Plant Health Program. A severe out­ Individual leaf blades may be curled of 6 to 8 in ches at each irrigation. If break of melting-out is difficult to stop and show black stripes with black pow­ the grass is a ll owed to become exces­ once it is in progress. There is such a dery spores that rub off from these sively dry and begins to go "dom1ant," large amount of the fungus pt·esent that stripes. The stripes run parallel with the and then is watered heavily, melting-out cultural measut·es will not reduce the leaf veins. When first developing, they ma y occur. The ct·own and root rot parasite s ufficiently to stop disease Figure 4. The white substance on the leaves are yellow-green. Later they turn gray phase of this disease occurs more read- development. In such cases plant- is the powdery mildew fungus. then black and may or may not be con-

6 7 rently with good resistance include War­ Symptoms ren's A-20 and A-34, Anheuser Dwarf, Baron, Belturf, Delft, Delta, Fylking, Light green patches of affected Kenblue, Park, Pennstar, and Sodco. plants, 2 to 6 inches in diameter, appear Very susceptible bluegrasses include fit-st (Figure 6). Later, the color changes Cougar, Merion, Newport, Prato, and in a 36-48 hour period to dull reddish­ Windsor. Common and Troy are mod­ brown, then tan, and finally a light straw erately susceptible. color. The patches may form elongate Creeping bentgrasses reported as sus­ streaks, crescents, or circles 2 feet or ceptible to stripe smut include Arling­ more in diameter. ton, Cohansey, Congressional, Evan­ In final stages of the disease, distinct sville, Old Orchard, Penncross, Pennlu, streaks and uniformly blighted circular Seaside, Toronto, and Washington. patches of diseased grass are scattered Resistance to these smut fungi may not throughout the lawn. Apparently be stable due to numerous races of each healthy green grass may occur within smut fungus. It is suggested, where the centers of patches of dead grass giv­ feasible, that yo u plant a blend rather ing a diagnostic "frog-eye" pattern. than a single variety. When idea l conditions for disease Certain systemic fungicides may be development exist for an extended Figure 7. Typical dollar spot leaf lesions on used to control smut fungi in bentgrass period of time, affected areas may over­ Kentucky bluegrass. and .bluegrass plants when applied as a lap, resulting in a completely blighted Figure 5. Leaves of a Kentucky bluegrass soil drench and watered in. The man­ area. Pink mycelial growth of the causal plant curled and shredded by stripe smut ufacturer's directions should be care­ fungus can sometimes be found in Water deeply to avoid drought stress. infection. fully followed . crowns of diseased plants which are dry Mow at the suggested height (page 3). and dark brown to black. Keep thatch to a minimum (below Y2 tinuous along the leaf blade. The leaf FUSARIUM BLIGHT inch) as excessive thatch provides an then twists, curls and shreds from the Cause ideal medium for the fungi to over­ tip downward (Figure 5). Infected This disease of lawns more than two winter and multiply. Fusarium blight is caused by FusaTium plants may die during hot dry weather. years old is becoming one of the most Bentgrasses, fescues, ryegrasses and Tosewn f. sp. cerea lis 'Culmorum' and F. In other instances, the symptoms disap­ troublesome in the eastern half of the bluegrasses are all susceptible to this dis­ pear or become "masked." tricinctwn f. sp. poae. F. roseum appears United States on bentgrasses, Kentucky to be more important and more widely ease, but varieties differ in resistance. bluegrass and red fescue. All lawn distributed. Both fungi survive the Merion Kentucky bluegrass is par­ Cause ticularly susceptible. grasses grown in the Midwest appear to wi nter in infected gt-ass roots, crowns be susceptible. Fusarium blight is caused Stripe and flag smuts are caused by and rhizomes and in the thatch la yer. Disease may be controlled by proper by a different fungus than that causing application of certain systemic fun­ Ustilago striiformis and Urocystis agropyri, High nematode populations predispose Fusarium patch or pink snow mold. respectively. Laboratory diagnosis is plants to injury by the Fusarium fungi. gicides. Carefully follow the manufac­ turer's recommendations. necessary to distinguish the two smut Poor cultural practices may weaken the fungi. Spores of these fungi germinate turf and predispose it to Fusarium in the soil and thatch where they may blight. SCLEROTINIA DOLLAR SPOT infect the buds on crowns and rhizomes Temperatures from 75 to 100° F of yo ung tillers. The fungi grow coupled with high humidity favor dis­ Symptoms throughout the plant tissues and remain ease development. Disease severity within the plant until it dies. Smutted appears to be directly related to the Dollar spot appears as round, brow­ plants in newly seeded lawns are drought stress to which the turf has nish or bleached-tan spots of turfgrass uncommon. Watering and high fertility been subjected. The disease may appear ranging from the size of a silver dollar favor their buildup. in 1-2 days during the summer when on bentgrasses to 4 to 6 inches in diame­ night temperatures are high. ter on bluegrass, fine-leaf fescues, Control zoysia, and Bermudagrass. If left Control unchecked, the spots may merge form­ Varieties of Kentucky bluegrass and ing large, irregular, straw-colored creeping bentgrass differ greatly in Figure 6. Fusarium blight. Apparently Maintain grass in vigorous growing patches of dead grass. resistance to stripe and flag smut. healthy green grass may occur within the condition, but avoid the use of excessive Individual blades are girdled with yel­ Varieties of Kentucky bluegrass cur- centers of patches of dead grass. nitrogen during hot summer weather. low to light tan lesions with reddish-

8 9 brown borders (Figure 7). When dollar drought and chemicals. During moist spot is active a white, cobwebby growth periods, when the soil temperature is (mycelium) can sometimes be seen on above 50° F, the sclerotia may send out the grass leaves while dew is still pre­ microscopic threads (hyphae) that sent. Injured turf recovers qutckly tf penetrate and infect grass plants. The treated promptly. If left untreated, it fungus does not produce spores. may take weeks or months for new grass Four conditions are necessary for to fill in the sunken dead areas. ] Rhizoctonia brown patch to develop: 1. Viable fungus must be present. Cause ] 2. Dense growth of a susceptible grass. Dollar spot is caused by the fungus, 3. A temperature of 70° to 95° F for Sclerotinia homoeocmpa. The disease may several hours. occur regardless of management or soil 4. Prolonged dew or a film of mois­ fertility. Damage is usually most severe ture on the foliage. if there is a deficiency or a great excess Figure 8. Brown patch. Most noticeable If any one of these conditions is lack­ of nitrogen. . . . early in the morning. ing, brown patch will not be severe. Dollar spot is most active dunng mmst The Rhizoctonia fungus grows out patches, up to several feet in diameter periods of warm (60-85° F) days and radially through the soil and thatch (Figure 8). Leaves are first water-soaked Figure 9. Rust lesions on bluegrass. The cool nights in spring, early summer ~nd from germinating sclerotia-hence the and dark, but soon dry, wither and turn lesions contain reddish dust-like material fall . The fungus overwmters as restmg circular spots of diseased plants. Under light brown. On closely clipped bent, a that readily rubs onto one's fingers or shoes mycelia in the thatch layer and infected hot a nd humid conditions the lower when walking through a rusted lawn. dark grayish-black ring of wilting grass plant parts. The fungus does not nor­ grass leaves touching the soil or turf mat often borders diseased areas. This ring mally produce spores. Spread occUJ-s are attacked. Infection then progresses !em until summer when extended dry is most noticeable early in the morning, from one area to another on infected up the pla nt and spreads to adjacent periods slow the growth of grass. Some disappearing as the grass dries. material that is blown or splashed about grass blades in the dew or exuded water varieties of Kentucky bluegrass (Adel­ In light attacks, turf generall y and carried on mowers, hoses, mainte­ on the leaf tips. phi, Delft, Merion, Prato and Windsor) recovers from brown patch in 2 or 3 nance equipment and shoes. Sclerotia may germinate and cause and the newer t-yegrasses are very sus­ weeks. When severe, however, the All lawn grasses grown in the Midwest infection an indefinite number of times ceptible. All lawn grasses grown in the crowns, rhizomes and roots may rot. are susceptible to attack. Bentgrasses, (30 or more) and survive in soil for a Midwest are attacked by one or more Such turf is killed or thinned out in especiall y certain strains of creeping number of years. The fungus is also kinds of rust fungi. large areas. Brown patch occurs in hot, bent, are very susceptible as are capable of surviving up to 4 months in Grass heavily infected with rust humid weather when night tempera­ bermudagrasses and zoysias. New seed­ dried grass clippings. becomes reddish-brown or ye llow­ tures are above 60° F, and leaf surfaces lings of tall fescue are also commonly o t-a nge. Close examination of the grass are covered with free moisture for long attacked. Control blades and leaf sheaths reveals powde ry, periods. rust-colored or yellow-orange spots Control Follow the suggested cultural prac­ (Figure 9). The powdery material rubs Cause tices outlined under Preventive Disease off easil y on your fingers, shoes or clo­ Follow the same cultural practices as Control (page 3) . Brown patch occurs outlined under Preventive Disease Con­ Brown patch is caused by the com­ thing. Continuous heavy in fection les~ frequently when avail able nitrogen causes many grass blades to turn ye ll ow , trol (page 3). Maintain adequate to high mon soil-borne fungus, Rhizoctonia sol­ supply in the soil is adequate or low and ani, which attacks all lawn grasses. wither a nd die. Severely rusted lawns fertility by following the recommended phosphorus and potassium levels are Bentgrasses and annual bluegrass are may winter-kill. lawn feeding program for your area. high . Apply a suggested fungicide The disease may be controlled by apply­ more seriously injured than the coarser 1 wee kl y in hot, humid weather following Cause ing certain fungicides starting when the bluegrasses, fescues and ryegrasses. the manufacturer's directions. Apply The fungus invades and kills the grass disease isfirst evident. Follow manufac­ when the temperature is 80°F or lower. The dusty material is composed of blades, leaf sheaths, stems, crowns and 1 turer's directions. Bentgrasses cut at golf green height millions of microscopic spores of rust roots. It overwinters principally in the ca nnot be grown without a preve ntive fungi (Puccinia spp.). The spores may form of small, hard, brown to black rest­ RHIZOCTONIA BROWN PATCH fungicide program. be carried about by air currents, lll0\1- ing bodies (sclerotia) that measure about ing, splashing water, on shoes, etc. Some Symptoms 1/16 of an inch in diameter. These form RUST land on healthy grass blades where, in in the thatch of infected plants or in the Symptoms the presence of moisture, th ey ger­ This disease appears in bentgrass turf top Y2 inch of soil. Sclerotia are minate and cause new in fections. Rust as somewhat roughly circular brown extremely resistant to cold, heat, Rust does not usually become a prob- fungi usuall y overwinter as dormant

10 11 Mamsmius oreades, Agmicus campestris or Lepiota nancina) which grow very exten­ sively in the area of the ring. Growth usually starts with a germinat­ ing spore at a central point and fungus h yphae grow outward equa ll y in all directions. Outward spread may occur at the rate of a few inches to two feet or more per year. The part of the fun­ gus on the inner side of the circle dies as the fungus grows throughout the soil forming a dense, white, tht·ead-like growth sometimes to a depth of eight Figure 10. A large fairy ring of fast­ inches or more. growing, dark green grass. Control mycelium in infected grass plants. The development of unsightly rings may be suppressed by fertilizing the Figure 11. Mushrooms growing in a lawn. Control lawn adequately with nitrogen several Keep grass growing in hot dry times a year, and pumping large quan­ fruiting structures of various kinds of These diseases are most severe in weather through adequate applications titi~s of water 10-24 inches deep into the fungi. These fungi grow on decaying northern pans of the Midwest where of nitrogen fertilizer and water. See soil, at 1-foot intervals, within the rings organic material in the soil. They are snow covers the g round continuously under Preventive Disease Control (page of dark green and thin or dead grass commonly found in areas of buried tree for three months or more. Attack ceases 3). Kentucky bluegrass varieties resis­ using a "root feeder" on a garden hose. stumps, dead roots, logs, boards or a when the grass surface dries out. All tant to several races and kinds of rust Repeat if rings reappear and grass starts thick thatch, and generally occur follow­ lawn grasses in the 1Vfidwest are suscep­ include: Warren's A-20 and A-34, Bel­ to wilt. ing heavy rains or watering. tible. Bentgt·asses are more severely turf, Fylking, Newport, Park, and Penn­ Fairy Ring is difficult to control attacked than coarser lawn grasses. star. Where needed, spray the grass because the infested soil is impervious Control These two snow molds are treated several times, at 7- to 14-day intervals, to movement of water. Probably the These fungi are difficult to control separately since chemical controls for with a suggested fungicide. Start when most effective method of control until all wood or other organic matter each are differen l. rust is first seen. involves careful removal of a ll sod upon which they grow has been com­ Typhula Blight or FAIRY RING within the ring and two feet to the out­ pletely decayed. In some cases it may side and sterilization of soil underneath be pt·actical to dig up the pieces of rott­ Gray Snow Mold Symptoms using a soil fumigant (e.g., methyl ing wood or other debris. It is usually Symptoms Fairy Ring appears as a circular ring bromide, formaldehyde, chloropicrin, best to break or mow off the of fast-growing, dark green grass often Vapan Soil Fumigant, Vorlex, etc.). The mush rooms o t- puffballs and let the fun­ Roughly circular, grayish, straw­ with a ring of thin or dead grass inside manufacturer's directions must be fol­ gus go ahead and complete decay of the colored spots seYeral inches to two feet or outside (Figure 1 0). Sometimes the lowed carefully. This treatment is matet·ial , after which the mushrooms or more jn diameter appear elut-ing ring is not complete, giving the appear­ laborious and costly and most people and puffballs will disappear. winter OF early spring in wet areas, usu­ ance of an arc or horseshoe. The rings prefer to "live wi th the problem." all y where snow is melting (Figure 12). vary in size from a few inches to 50 feet SNOW MOLDS Several circles may merge to form large or more in diameter. The strip of thin MUSHROOMS, PUFFBALLS irregular areas. Where severe, the or dead grass varies from 3 to 6 inches Symptoms There are two types of snow mold in entire lawn may be affected. in width. After rains or heavy watering the Midwest, Typhula blight or gray A crust-like mat of hyphae may form Everyone has seen mushrooms (toad­ many mushrooms may appear in the snow mold and Fusarium patch or pink where grass has been left tall. Diseased stools) and puffba lls (Figure 11). dark green grass. Occasionally the sym­ snow mold. Both diseases are most seri­ areas are covered with a fluffy, bluish­ Sometimes they may be quite annoying. ous when air movement and soil drain­ to dirty-gray mycelium or mold growth ptoms may appear as "dry patches" in Some are foul-smelling; a few are lawns instead of a ring. All turfgrasses age are poor and grass stays wet for long when snow is melting or grass is wet. poisonous and a menace to children and are subject to invasion. periods with temperatures near freez­ At other times a silvery membraneous pets. ing. Damage often conforms to foot crust develops over the diseased turf. Cause prints, paths, snowmobile or ski tracks, Fairy Ring is caused by a number of Cause etc., because snow compaction and plant Cause soil-inhabiting mushroom fungi (usually Mushrooms and puffballs are the injury favor the disease. Typhula blight is caused by several

12 13 fungicide where Typhula occurs each the fungus produces tremendous num­ year. Apply up to a month before the bers of microscopic spores. Lawn equip­ first lasting snow fall. Where possible, ment, shoes, air currents and water repeat during a mid-wintet- thaw. carry the spores to grass blades where infection occurs. Disease development is Fusarium Patch or optimum when snow falls on unfrozen ground, air temperature is 32° to 45° F, Pink Snow Mold and the humidity is very high. Symptoms Control

Round, bleached-tan or whitish~gray Follow the same cultural practices as to reddish-brown patches of affected for Typhula blight. Avoid overfertiliz­ plants, usually I to 8 inches in diameter; ing with nitrogen. Somewhat resistant sometimes enlarging to a foot or two bentgrasses include Cohansey, North­ land, and Pennlu. For high mainte­ Figure 12. Snow mold injury to grass. across are usuall y observed. At the advancing edge of melting snow the nance turf, apply a suggested fungicide species of Typhula, primarily Typhula spots may have pinkish margins. starting in the fall when daytime tempe­ itoana.. All require snow cover for dis­ Fusarium patch· does not require a ratu res remain below 60° F and the ease development. When active, and snow covet- fot- development. Disease weather is wet. Additional sprays may snow is melting, the fungus produces attacks can occur anytime during cool be needed during winter and spring Figure 14. Pythium blight on bentgrass. small (up to 3/16 inch), hard, light- to (below 60° F), wet weather in fall, winter when cool, wet weather persists. chocolate-bt-own sclerotia which are or spring. Under a snow cover or dur­ often embedded in the leaves and ing prolonged cool, wet weathet- dis­ PYTHIUM BLIGHT crowns of diseased plants. eased areas may be covered with a (GREASY SPOT, one of two species, Pythium aphanider­ The sclerotia later shrink and become dense, slimy mat of white myce lium that matum and P. ultimum. They are com­ difficult to see with the naked eye. The turns a faint pink when exposed to light COTTONY BLIGHT) mon soil-borne fungi present in dis­ Typ!wla fungi survive from season to (Figure 13) . eased turfgrass as dormant mycelium or season as sclerotia. When light is absent, Symptoms thick-walled resting spores (oospores). under a snow cover and generally ovet­ Either species can grow very rapidly, unfrozen ground, the sclerotia ger­ Cause Round to irregular spots of diseased plants up to 6" in diameter often appear from plant to plant. Long distance minate and pt-oduce m ycelia and Fusarium patch or pink snow mold is during hot, wet weather. The spots are spread is by flowing water, equipment, basidiospores that infect the grass. caused by Fusarium nivale. The fungus first water-soaked and dark, then fade and infested soil. The fungi are most T here is little fungus activity when the surviv es from season to season as active when air temperatures are 85° to ground is frozen with no snow cover. myce lium and spores in infected grass to a light brown as the leaves dry out and wither. 95° F (minimum night temperature of T)'phula can grow and infect plants in plants or thatch. When temperature A greasy border of blackened, matted 68° F) and air is saturated on heavy, the spring when snow is absent pro­ and moisture conditions are favorable, grass blades, often covered with a cot­ poorly drained soils where grass is \' icl ed the weather is cold (30° to 45° F) tony mass of fungus myce lium, is seen dense and lush. and wet. This might occur f01- a couple when Pythium is active (Figure 14). The or clars but not much longer. patches may merge and form streaks Control Control since the fungus is spread by flowing Follow the suggested cultural prac­ wa ter and mowing. The disease may tices as outlined under Preventive Axoicl late fall applications of fer­ spread very rap id ly, killing out large Disease Control (page 3) . Maintain a ti li zers comaining nitrogen. Follow cu l­ areas of turf overnight. proper balance of nutrients, avoiding an tural recommendations for your area. Seedlin gs in new turfgrass areas may excess of nitrogen that stimulates lush :\n a,·erage daLe beyond which 1101 Lo wi lt, collapse and d ie in patches (see growth. Improving surface and subsur­ ferti li ze is three months before the first Dam ping-off). Girdling, straw-colored face soil drainage will aid greatly in con­ .. permanent·' or lasting snow. les ions witho1ll conspicuous borders trolling Pythium blight. Where feasible, 'do\\ frequently and keep the g rass occur on bluegrass leaf blades, resemb­ delay seeding until weather is cool and cut to it s suggested height to prevent a ling those of Sclerotinia Dollar Spot. dry. Seed only at suggested rates. Do bean· mat of grass from forming. Fol­ not overwater. Apply a recommended Io\\· other Preventive Disease Control Figure 13. Pink snow mold. Margins of Cause fungicide when hot, rainy or foggy practices (page 3). Apply a suggested spots may be pinkish. Pythium blight is usually caused by weather is forecast.

14 15 SEPTORIA LEAF SPOT is common o n all grasses grown in the may cause this disease. Attacks are most Many gene ra and species are present Midwest, be in g most prevale nt in red severe during wa rm weather on heavy, in turf, bu t o nly a re la ti ve ly few are AND TIP BLIGHT fescu es, Ma nh attan r yegrass, a nd moist o r water-logged soils and wh e re injurious in the Mid wes t. T hey survive bentgrasses. seeding ra tes have been excessive. in the soil o r grass debris as eggs, cysts . Symptoms o r la rvae. With the ad ve nt of warm spr­ Control The overall appearance of an infected Cause in g weathe r they become active a nd la wn rese mbles injury from a dull penetrate into grass roots o r suck cel­ Corticium re d thread is caused b y Sow to p q ua lity seed o nl y a t suggested lula r co nte nts by inserting a hollow mower. The leaf blades are light yell ow ra tes, in a we ll-pre p a r e d , fe rtile stylet into the root ti ss ues. from the tip downward. Close exa mina­ CoTticium fucifomze. C ha racte ri sti c o f both the disease and fungus is the for­ seedbed . Provid e for good sui-face and Ne ma todes ca u se wo unds through tion usua ll y shows black dots (pyc nidia, subsurface soil dra in age whe n establish­ ma tio n of bright, cora l-pink to red which disease-producin g fungi may the fruiting bodies of the SeptoTia fun­ in g a new law n. Fill in low spots where e nte r . The presence a nd ide ntity Qf gus) e mbedded in the diseased tiss ue. "threads," about 1/1 6 to V4 in ch lo ng, which protrude fro m diseased leaf tips water may sta nd . Treat seed be fo re pla nt-parasitic ne matod es ca n only be Younger , sma ll e r lesions, Ys inch o r a nd leaf sh eaths. These a re fun g u s planting by dusting tho roughl y with a determined by taking plugs of sus­ more in length , with red or ye ll ow ma r­ thi ra m o r ca p tan seed pro tecta nt (\12 strands that appear gelatino us in early pected turf with soil attached and hav­ gins, may also be present. morning and are j o ined by a pink web teaspoonful per pound of seed). Avoid in g the m examine d by a compe te nt over watei-ing. If possible, seed in late of myce lium. Later the stro mata become ne ma tologist. Cause summer or earl y fall. T he next best time brittle a nd thread -like as the g rass is early spring. See also Pythium blight The disease is caused by species of blades dry. Control fo r care of newly germinated seedlings. Septaria acti ve during cool, wet weather The fun gus ove rwinte rs in in fected in spring and fall. The fungi survive the grp.ss debris. It can survive for at least Keep grass g r owin g vigoro u sly by waterin g, fe rtilizing a nd fol lowing winte r as m yce lium and pycnidia in tw o years in the soil. The f un g us is NEMATODES Preventive Disease Control measures d ebris. During cool spring ra ins, the spread from one area to a n o the r by spo res a re splashed to healthy leaves spo res or as fungal stra nds and infected Symptoms (page 3). If seve i-e, apply a su ggested where infection occurs, often in the cut leaf pa rts o n law n equipme n t, shoes, ne m a ticide s uch as Nemagon or ends of the grass blades. Septori a leaf wa te r , e tc. Re d thread is us ua ll y o f Heavil y ne ma tode-infested turf lacks Fumazone foll owing the ma nufacturer's directi ons. spot is usua ll y of mino r importance dur­ minor impo rtance. vigor, ofte n appears off-color, ye ll ow, ing the summe r. bunchy, and stunted. Grass blades dying Control back fro m the tips may be in terspersed SLIME MOLDS Control with appa i-ently hea lthy leaves. Injured Follow the Preve ntive Disease Control t u rf m ay thin o ut, wil t a n d die in Symptoms Foll ow the Preve ntive Disease Control practices on page 3 a nd che mica l con­ irregul ar a reas. T he severity of sy m­ practices on page 3 to maintain a vi gor­ trols as for Melting-out and Sclerotinia ptoms va ri es with the type of pl ant­ T hese norma ll y harmless fungi fre­ o u s turf. Whe re severe, fun gicid es Do ll a r Spot. Ma in taining a ba la nced , parasitic ne matode po pulati o n feeding que ntly cause considera ble alarm. They applied to control Me lting-out sho uld hig h fe rtility leve l is important as is o n and in the I-oots. suddenly appear in spring, summe r or pro vide ad equa te contro l. Ke ntucky tha tch re moval a nd the coll ectio n o f Sympto ms are easil y confused with fa ll following heavy rains o r watering. bluegrass va rieti es differ in resistance to clippings. so il nutri ent defi ciencies, poor so il aera­ Small , water y-white, gray, cream or ye l­ Septo ri a Leaf Spo t. tion, d ro ught, insects, a nd other ty pes low slimy masses grow over the grass in DAMPING-OFF, SEED ROT of injury. Nema tode-infested grass does ro und to ir regular patches, smothe ring CORTICIUM RED THREAD, not respo nd no rma ll y to water and fer­ o r shading othe rwise healthy grass. The PINK PATCH Symptoms tili zer. Da maged roots may be swoll en, masses dry and fo rm unsightly bluish­ sha ll ow , "stubby," bushy, a nd d ark in gray, gray, black, white or yell ow pow­ Symptoms Seeds rot in the soil. T he grass stand color. de ry structures (Fig ure 15), the fruiting is thin a nd weak in irregul ar patches. stage of the cau sa l fun gus. Whe n Round to irregular, light-tan to pin­ Seedlings a re stunted , wa te r-soaked , Cause crushed between the fingers, they disin­ kish patches of blighted grass, usua ll y turn yellow to brown; may wilt and col­ tegrate into a powde ry mass tha t easily 1" to 6" in diame ter, develop during cool la pse. Surviving pla nts are weake ned. Ne matodes are microscopic, slender rubs free from the grass blad e. (60° to 7 5° F) , moist weather in spring Stand is slow to fill in. Affected areas round wo rms (sometimes called eel­ and fa ll in sl ow-growing turf. Whe re ai-e often heavil y in va ded by weed s. worms o r ne mas) . Most ne ma tode ty pes Cause severe, the spots may merge and form are harmless, feeding upo n decompos­ large, irregular, bleached-tan a reas with Cause ing o r gani c m a teria l a nd o the r soil Slime molds are pnmlt!ve, soil­ a reddish-brown cast tha t resembles o rganisms. A fe w are benefi cial to ma n inhabiting fungi (mostl y Mucilago spon­ melting-o ut. Sympto ms on be rmudag­ N umerou s soil-borne fungi (es­ sin ce they are pa rasitic on pla nt-feeding giosa, Physarum cineTeum, etc.) tha t utilize rass resemble "winter-kill." The disease pecia ll y Pythium a nd Rhizoctonia spp.) ty pes. d eca ying o r ganic ma te ri a l a nd other

16 17 tilizers, pesticides, hydrated spray lime) range (below pH 5.5 or above 7.3) check tility, with poor drainage, high soil acid­ may injure grass if improperly applied. with your county Extension office on ity, excess shade, compaction or a com­ Burned areas may occur in spots or what and how to bring the soil within bination of these factors. streaks, or the entire lawn may be "s­ the desired range. corched." Prevent injury by following Control the directions printed on the package Buried Debris label. Apply fertilizers evenly in recom­ Remove moss by hand raking. Cor­ mended amounts, when the grass is dry. A thin layer of soil over buried rocks, rect the unfavorable condition(s) by fol­ Then water immediately. The use of a lumber, bricks, plaster, concrete, etc., lowing Preventive Disease Control prac­ calibrated lawn spreader is highly dries out rapidly in dry summer tices (page 3). Have a soil test made and recommended. Ground agricultural weather and may resemble disease. follow instructions given in the report. limestone is safer to use on lawns than Control by digging up suspicious areas, hydrated lime. removing the cause, and adding good Dog Injury topsoil. Injury from urine may resemble Chlorosis, Yellowing Rhizoctonia brown patch or Sclerotinia Figure 15. The whitish growth on the grass Compacted Areas dollar spot. Affected areas are often blades is slime mold. Areas or all of the turf may become Thin turf or bare spots appear in more or less round and commonly up ye llowed and stunted. Chlorosis (ye l­ microorganisms in the soil as a food heavily used areas. Waterlogged and to a foot or more in diameter. These source. They are not parasitic on plants. lowing) is usually caused by nitrogen, are usually bordered by a ring of lush, iron deficiency, or temporary water­ heavy-textured soils become compac­ In humid weather slime molds grow out ted; later bake hard if walked on con­ dark green grass. Injured grass turns of the soil and thatch onto whatever is logging of the soil. Most lawn fertilizers brown or straw-colored and usually contain niu-ogen. If a recommended stantly. Water flows off these areas and available for support and produce their plants may die of drought. Correct by dies. Heavy watering helps spots to fertility program is carried o ut (see page spore masses. A well-watered, well­ aerifying the soil with an aerifier (can recover. 3) this element is probably being applied fertilized lawn provides an ideal envi­ be rented at garden supply stores) or ronment. in sufficient amounts. If the lawn con­ Read the entire pesticide label tinues to t-emain yellow after nitrogen installing drainage tile for seriously Control application followed by rain or water­ water-logged soils. This allows water -what the chemical is ing, the cause is likely to be iron defi­ and air, necessary for root growth, to - the diseases it controls If left alone, the slime mold soon dis­ ciency. This is most likely if the soil is penetrate into the soil. If necessary, fer­ -how much to use appears. However, if yo u wish, mold either highly acid or alkaline. tilize and reseed. Reduce foot traffic on -when to use growth may be removed by raking, lawn by putting in a walk, patio or park­ brushing, mowing or h osing with a ing area; erect a fence; or plant a shrub stream of water. Fungicides applied to Control or two . Apply only as directed control Melting-out, Rhizoctoni a Brown Patch or other diseases should keep Have a soil test made and follow Al gae or Green Scum ---controls will be more slime molds in check. Reduce accumula­ directions in the report. If iron defi­ effective tion of thatch . ciency is the problem, apply four tables­ A green to blackish scum may form ---chances of plant injury poons of iron sulfate (sold as o n bare soil or thinned turf in low, wet, are reduced OTHER CAUSES OF "Coppet-as" or "Sulfasoil") in 5 to 10 gal­ shaded or heavily used and compacted areas. The slimy mass of algae (minute, POOR TURF lons of water per l ,000 square feet. Handle pesticides carefully Sprinkle in immediate ly. Repeat the single-celled, filamentous plants) dries Insect Injury to form a thin, black crust that later treatment as necessary to maintain nor­ - take proper precautions cracks and peels. Numerous insects, including grubs, mal green color. Avoid spray drift with children and pets webworms, chinch bugs, ants, leafhop­ because iron sulfate leaves a brown stain -avoid drift pers and others may damage turf. on the gt-ass blades. Co ntrol -wear protective clothing Insect injury may closely resemble one Iron ch e late materials a lso correct Follow the cultural practices outlined iron deficiency. When starting a new if specified or more lawn diseases. If you suspect under Preventive Disease Control (page lawn, have the soil tested before plant­ ---clean-up immediately a lawn insect problem contact your 3); including correcting soil and air in g . This can be clone, usually for a county Extension office or the Exten­ drainage. When necessary, an algacide after application small service charge, by your state uni­ sion entomologist at yotll- land-grant may be desirable. -safely dispose of empty university. venity, county Extension office, or a containers Chemical Burn private soil testing laboratory. The pH Moss -keep and store in the of the soil should be close to neutral (pH original containers Agricultura l chemica ls (e.g., fer- 6.0 to 7.0). If the pH is far outside this Moss occurs in lawn areas low in fer-

18 19 1973 TURF DISEASE CONTROL GUIDE Rates listed below give a range-use the lower rates for routine preventive control and the higher rates for curative treatments.

Time of Disease Fungicidesa Rated application Leafs pot Captan 50 W 4-6 April to June every 7-14 (Melting-out Daconil 2787 75 W 4 days. Going-out) Dyrene 50 W 4-8 Helminthosporium spp. Fore 80 W 4 Tersan LSR 80 W 3- 8 Fusarium blight Tersan 1991 50 W 5-8 Apply in June to August. Fusarium roseum Cleary's 3336 50 W 2-4 Fungo 50 Wh 4-8 Brown Patch Acti-dione-Thiram we 2-4 June to August 7-14 days Rhizoctonia solani Captan 50 W 4-6 as required. Daconil 2787 75 W 4-8 Dyrene 50 W 4-8 Fore 80 W Fungo 50 W h •2 Kromad W 3 Mertect 140 F 2 Tersan LSR 80 W 3-4 Tersan 1991 50 W 2 Tobaz W 2 Dollar Spot Acti-dione-Thiram we 2-4 June to August 7- 14 days Sclerotinia homeocarpa Daconil 2787 75 W 4-8 Dyrene 50 W 4-8 Fore 80 W 6-8 Fungo 50 Wh I Kromad W 3 Mertect 140 F 2 Tersan 1991 50 W I Tobaz W 2 Rust Acti-dione-Thiram W' 2-4 July to September 7-14 Puccinia spp. Daconil 2787 75 W 4-8 days as required. Dyrene 50 W 4-8 Fore 80 W 4 Tersan LSR 80 W 3-4 Zineb 75 W 2 Powdery Mildew Fungo 50 Wh 4-8 One or more as required Erisiphe graminis Spring or Fall . Sulfur W Sulfur: follow directions on label. Strir.e Smut Fungo 50 Wh 4-8 2 applications spring or Usttlago striiformis fall. Tersan 1991 50 W 6-8 I application spring or October. Snow mold Calo-Gran (lb) 6-10 I application late fall, Typhula spp. Calo-Clor 45 W 3 Oct-- Dec. Tersan-SP 65 W 6-9 Repeat I-3 times during Thiramad 75 W 8 winter-Follow directions on the label. Fusm·ium nivale Daconil 2787 75 W 4-6 Dyrene 50 W 6-8 • W =Wettable powder. b Experimental label-limited supply available. c Acti-dione-Thiram-may be injurious to plant with use at high temperatures or by exceeding recommended rates. • Rate formulation ounces/ 1000 sq ft in 5-10 gal water. A typical control program would be 2-3 applications of a fungicide (contact) in the spring to control leaf spot and followed by 1- 3 applications of a fungicide (systemic) for control of Fusarium b light if necessary. Follow directions on the label. Speci al disease problems such as rust, mildew, dollar spot, smut and brown patch should be treated with a fungicide as required.