IPM Prescriptions for Some Common Diseases
of Ornamental Plants and Turfgrasses

Following are general IPM prescriptions for some common diseases of ornamental plants, including bacterial canker, brown rot, black spot, rust, powdery mildew, crown gall, sooty mold, tulip blight, damping-off fungus; and turfgrasses, including brown patch, dollar spot, fusarium blight, fusarium patch (pink snow mold), gray snow mold (typhula blight), red thread, take-all patch, turf anthracnose.

Bacterial Canker

Target/Host
Japanese flowering cherries. Prunus yedoensis 'Akebono' has shown strong resistance.

Potential Indirect Treatment Strategies

Cultural

Trees grown with adequate nitrogen levels in the soil are more capable of recovering. Avoid planting susceptible species in shallow or sandy soils.

Design and Construction

Avoid the use of Japanese flowering cherries altogether or at least as a major design component. If flowering cherries are felt to be necessary in the context of the design, Prunus yedoensis 'Akebono' should be considered as a preferred option from a maintenance perspective.

Manual

Prune off affected branches at least several centimeters below the canker in the summer. Severely infected trees should be removed promptly to prevent spread of the disease.

Brown Rot

Target/Host
Japanese flowering cherries are most severely affected, but flowering plum and quince are also hosts. Prunus yedoensis 'Akebono' has shown strong resistance.

Potential Indirect Treatment Strategies

Cultural Management

Prune in a manner that allows maximum air circulation and drying within the canopy. Collect and remove potentially infected litter during spring, summer, and fall.

Design and Construction

Avoid the use of Japanese flowering cherries altogether or at least as a major design component. If flowering cherries are felt to be necessary in the context of the design, Prunus yedoensis 'Akebono' should be considered as a preferred option from a maintenance perspective.

Manual

Prune off diseased twigs and flowers as soon as they are noticed. Disinfect tools in a bleach solution after each cut. Severely infected trees should be removed promptly to prevent spread of the disease.

Chemical

No known cures exist once infection has taken place. As a preventive measure, Bordeaux mixture, other copper-containing fungicides, or chemical fungicides may be applied at budswell with additional applications at full bloom and petal all if the weather has been rainy. Micronized sulfur may also be used; spray during popcorn, full bloom, and petal fall stages. If Bordeaux mixture is used after leaves begin developing, use additional lime to minimize damage due to copper toxicity.

Black Spot

Target/Host
Roses. Use disease-resistance species/varieties to the extent possible.

Symptoms/Typical Damage
Mild infections may only manifest as small black flecks that cause little damage. Severe infections cause leaves to yellow and drop off, often defoliating plants by midsummer. Infections on the canes can be identified as dark blotches on the wood.

Natural Controls

"Forces of Nature"

Limiting factors are temperature and humidity levels. (See "Description and Biology" above.)

Cultural Management

Keep foliage of susceptible roses as dry and well ventilated as possible. This can be achieved by: using drip rather than overhead irrigation; watering during sunny days if overhead irrigation is used; planting in full sun; spacing approximately 1 meter apart; and pruning to reduce foliage density.

Regular transplanting of roses with the crown located approximately 5 cm below grade is thought to increase vigor, disease resistance, and winter hardiness. This causes the plant to root from the crown stock and avoids basal shoots from the grafted root stock. The ideal time is early fall but transplanting can occur throughout the dormant season.

Habitat Modification

Replace particularly susceptible and problematic plantings with disease-resistant species/varieties or alternate plant species.

Design and Construction

Avoid using rose species/varieties that are known to be particularly susceptible to diseases as a major design component. If necessary in a design, locate plants: 1.) on the down side of prevailing winds to minimize spread of disease to other plants; and/or 2.) in blocks rather than mixed with varieties that are not as susceptible, to concentrate plants that may require fungicide treatments.

Manual

Prune and burn infected leaves, petals, and canes during the growing season as soon as detected. If plants have been heavily infected the previous growing season, prune to within 10-15 cm of the graft.

In mild winters and generally mild climates such as in the coastal regions of the Pacific Northwest roses may not go fully dormant, making disease removal more difficult. In this case roses should be "pruned into dormancy" and rose litter removed in January. Any small, weak wood that would not support a bloom should be removed. Experience at the Owen Rose Garden in Eugene, Oregon indicates that healthy canes are rarely bothered by disease unless located near infested, weak stems.

Physical

Mulch rose bushes after fall cleanup and again after mid-winter pruning. This helps to contain spores under the mulch to minimize dispersal.

Chemical

Safer Natural Garden Fungicide is a new fatty acid-based soap product that is reported to be effective at preventing the onset of black spot but will not control the disease once it has developed. Where black spot is historically a problem, apply to all new growth every 10-14 days as a preventive measure. This new product is not phytotoxic to roses and also kills pest mites but not beneficial mites.

Sulfur can aid in the control of black spot when used in conjunction with the other non-chemical methods described. If conventional fungicides are permitted and become necessary, limit their application to individual plants (i.e, it is not necessary to treat unsusceptible varieties). They have a tendency to cause secondary outbreaks of pest mites.

"Most of the available fungicides [including sulfur] are more effective at preventing infections rather than at curing them. Thus, to protect roses and keep use of fungicides to a minimum, it is important to time treatments to coincide with periods of optimum temperature, humidity, and rainfall, as well as with the growth stage of the rose. . . . Remember that roses are most susceptible to infection when they are in a state of rapid growth. By becoming aware of the growth cycles of your plants - in spring and early summer, moderate growth in midsummer and a possible surge of growth in late summer- and by correlating these cycles with weather patterns that encourage disease development, you will learn how often it is necessary to apply fungicides." (Olkowski, Daar, and Olkowski)

Rust

Optimum conditions for rust infection are temperatures between 18C and 21C with two to four hours of constant moisture. Overwintering spores are black, appearing on the leaves and canes in the fall.

Rust overwinters inside infected canes and points of infection are observed as dark, corky blotches. Distribution of the spores is through wind and water.

Target/Host
Roses and other ornamental shrubs. Use disease-resistance species/varieties to the extent possible.

Symptoms/Typical Damage
Aesthetic damage occurs as the disease spreads to upper leaf surfaces, sometimes covering a significant portion of the canopy. Severe infestations can cause defoliation of affected leaves.

Indirect Treatment Strategies

Cultural Management

Keep foliage of susceptible roses as dry as possible. This can be achieved by: using drip rather than overhead irrigation; watering during sunny days if overhead irrigation is used; planting in full sun; spacing approximately one meter apart; and pruning to reduce foliage density.

Habitat Modification

Replace particularly susceptible and problematic plantings with disease-resistant species/varieties or alternate plant species.

Design and Construction

Avoid using rose species/varieties that are known to be particularly susceptible to diseases as a major design component.

Manual

Prune and burn infected leaves, petals, and canes during the growing season as soon as detected. If plants have been heavily infected the previous growing season, prune to within 10-15 cm of the graft. In mild winters and generally mild climates such as in the coastal regions of the Pacific Northwest roses may not go fully dormant, making disease removal more difficult. In this case roses should be "pruned into dormancy" and rose litter removed in January. Any small, weak wood that would not support a bloom should be removed. Experience at the Owen Rose Garden in Eugene, Oregon indicates that healthy canes are rarely bothered by disease unless located near infested, weak stems.

Physical

Mulch rose bushes after fall cleanup and again after mid-winter pruning. This helps to contain spores under the mulch to minimize dispersal.

Chemical

Safer Natural Garden Fungicide is a new fatty acid-based soap product that is reported to be effective at preventing and eradicating rust. Apply every 7-14 days when humidity is high and temperatures are approximately 20C. See prescription for black spot for further information regarding this product. Sulfur is also helpful for control of rust but should be used in conjunction with the other non-chemical methods described. If conventional fungicides are permitted and become necessary, limit their application to individual plants.

Powdery Mildew

Optimum conditions for the disease are nighttime temperatures of 16C with a relative humidity between 95 and 99%, and daytime temperatures of 27C with 40-70% relative humidity. Cloudy and foggy periods enhance the growth of the disease.

Overwinters inside leaf buds on canes, especially just below infected flowers. Dispersal is by wind. Young, succulent growth is preferred; mature tissue is usually not affected.

Target/Host
Roses, azaleas, euonymus, hydrangea, aster, chrysanthemum, phlox, verbena, turf, and other common ornamental landscape plants.

Natural Controls

"Forces of Nature"

Limiting factors are temperature and humidity levels. (See "Description and Biology" above.)

Cultural Management

Avoid heavy applications of high nitrogen fertilizer and heavy pruning during the growing season. This causes excessive succulent and weak new growth which is ideal habitat for powdery mildew.

Habitat Modification

Replace particularly susceptible and problematic plantings with disease-resistant species/varieties or alternate plant species.

Design and Construction

Avoid using species/varieties that are known to be particularly susceptible to diseases as a major design component. Choose varieties of susceptible species known to be resistant to powdery mildew.

Manual

Powdery mildew cannot survive if there is a film of water on the leaves or stems. Washing new growth with a heavy stream of water removes spores and also helps prevent remaining spores from germinating. Begin as soon as conditions are conducive to growth of the disease at intervals of once or twice a week for a few minutes; early afternoon is the best time. Continue until new growth matures and resume when other flushes of new growth coincide with favorable environmental conditions for the disease. Although wetting the plants can enhance the likelihood of black spot and rust, optimum conditions for both diseases typically do not occur simultaneously.

Prune and burn infected leaves, petals, and canes during the growing season as soon as detected. If plants have been heavily infected the previous growing season, prune to within 10-15 cm of the graft. In mild winters and generally mild climates such as in the coastal regions of the Pacific Northwest roses may not go fully dormant, making disease removal more difficult. In this case roses should be "pruned into dormancy" and rose litter removed in January. Any small, weak wood that would not support a bloom should be removed. Experience at the Owen Rose Garden in Eugene, Oregon indicates that healthy canes are rarely bothered by disease unless located near infested, weak stems.

Physical

Mulch rose bushes and other susceptible shrubs after fall cleanup and again after mid-winter pruning. This helps to contain spores under the mulch to minimize spread.

Biological

Research relating to the use of several fungus species as biocontrols for powdery mildew is being conducted at the University of Oregon and in Israel.

Chemical

Safer Natural Garden Fungicide is a new fatty acid-based soap product that is reported to be effective at preventing and eradicating powdery mildew. Apply every 7-14 days during cool, dry weather when roses are in an active growth phase. This new product is not phytotoxic to roses and most other ornamental plants and also kills pest mites but not beneficial mites.

Antitranspirants (e.g., Wilt Pruf) form a barrier between disease spores and leaves. Various research and field tests, including at Longwood Gardens in Delaware, have indicated antitranspirants to be at least as effective as conventional fungicides in controlling powdery mildew. However, further research is needed to confirm this, refine application timing and techniques, and verify that the antitranspirants don't cause any undesirable effects when used in this matter in various climates.

Baking soda may also be effective at controlling powdery mildew; research is being conducted in Japan and by the Henry Doubleday Research Society in Great Britain. Sulfur is effective at controlling powdery mildew and can be used in conjunction with the other non-chemical methods described.

If conventional fungicides are necessary, limit their application to individual plants. They have a tendency to cause secondary outbreaks of pest mites. (See Black Spot prescription for quote from Olkowski, Daar, and Olkowski about fungicides.)

Crown Gall

Target/Host
Rose, euonymus, honeysuckle, wisteria, aster, daisy, chrysanthemum, and many other species, particularly plants in the rose family.

Symptoms/Typical Damage
Rough, warty galls of 5 cm or greater develop on roots and/or lower stems, especially at graft unions. Plants become weakened or stunted. Damage is most severe where crown gall has already been present and where infected plants are allowed to remain, and is particularly serious on young plants.

Indirect Treatment Strategies

Cultural Management

Avoid wounding susceptible plants during cultivation to the extent possible. When pruning away infected parts of plants, tools should be disinfected regularly to prevent further spread.

Design and Construction

Avoid using susceptible plant species in beds that are known to be infected. As a preventive measure, thoroughly inspect nursery stock for symptoms prior to planting and only obtain nursery stock of susceptible species that have been treated with the microbial pesticide Agrobacterium radiobacter (e.g., Galltrol). "Crown gall can be largely prevented if you select plants free of galls and avoid injury to the roots and trunk during planting." (Harris)

Manual

Galls should be pruned out and destroyed whenever detected. Severely infected plants should be removed, particularly when planted near other susceptible species (i.e., in a rose garden).

Biological

Young plants are effectively protected when treated with a root dip solution of Agrobacterium radiobacter (e.g., Galltrol). Susceptible species that have already been planted may be treated with a soil drench to prevent future infection. However, any previous infection will not be controlled.

Chemical

Soil fumigation treatments have been used with limited success due to the difficulty in killing all of the bacteria and the ability of the residual organisms to rapidly multiply in the soil following such treatment.

Sooty Mold

Target/Host
Plants infested with aphids, scales, and other honeydew-producing insects. Also, plants that have honeydew falling on them from infested shrubs and trees above.

Symptoms/Typical Damage
Does not directly infect affected plants. Damage is largely aesthetic but can affect health of plants by inhibiting photosynthesis.

Potential Indirect Treatment Strategies

Cultural Management

Exclude ants if they are guarding honeydew-producing pests.

Habitat Modification

See description under manual treatment strategy below.

Design and Construction

Avoid using plants that are known to be particularly susceptible to aphids and scales as a major design component. If trees prone to aphid or scale infestation are used, avoid placing ornamental plants underneath. Such trees would best be used in a large grassy area away from other plants.

Manual

Remove honeydew and mold by washing leaves with soapy water.

Tulip Blight

Target/Host
Tulip spp. and hybrids.

Potential Indirect Treatment Strategies

Cultural Management

Monitor for diseased bulbs and discard. Do not plant tulips where previously infected plants have been grown. Buy new bulbs each year rather than saving dug bulbs. "Early removal of infected plants is essential. As soon as the disease appears in a bed, individual plants should be removed in such a way as to avoid scattering the spores or leaving parts of infected bulbs in the soil. Destroy all blossoms and leaves that show infection. If bulbs are to be planted where diseased plants have been grown, the soil should be replaced, steam-pasteurized, or treated with an appropriate chemical. Avoid the application of too much nitrogenous fertilizer." (Pirone)

Design and Construction

Avoid using tulips as a major design component in areas where tulip blight has previously occurred.

Manual

Remove infected plants immediately upon detection of disease.

Chemical

Frequent applications of the fungicides Botran and Fore have been demonstrated to be very effective, but in rainy springs thorough applications are necessary as often as every three days. However, this is not considered a valid treatment strategy within the context of an IPM program.

Damping-off Fungus

Target/Host
Any seedlings grown in infected soil and humid conditions.

Potential Indirect Treatment Strategies

Cultural Management

Avoid sowing seeds too close or deep in the soil when possible. Provide well-drained soil and avoid overwatering. Expose plants to sunlight so they can keep dry. Inoculating seeds with Trichoderma (present in preparations of "compost tea", some commercial soil amendments, etc.) has shown good results in preventing damping-off. Soaking seed in a brine or wood ash and lime solution for several hours is a traditional method of minimizing occurrence of the disease.

Habitat Modification

Use pasteurized soil, either purchased new or treated in an oven. Disinfect tools by soaking for thirty minutes in a household bleach solution (one part bleach to nine parts water) or hot water.

Chemical

A 2 percent solution of household bleach (2 1/2 ounces bleach per gallon of water) applied as a soil drench can halt the development of the fungus in flats of cuttings and seedlings. (Olkowski, Daar, and Olkowski) Oxine benzoate (e.g., No Damp) mixed in with irrigation water for seeds and seedlings has also shown effectiveness. A reader in Fine Gardening magazine reports effective control results with chamomile tea (1 bag/4 cups of water steeped for 24 hours to make a strong solution; apply with a mister to seedlings as soon as they appear until the second set of leaves have developed).

General Discussion
In order for turfgrass diseases to actively infect the turf, all of the following factors need to be present: the disease organism, a host plant, favorable environmental conditions, and a means of distribution of the spores.

Other factors that trigger most turf disease are: high relative humidity and/or the movement of surface water over the grass for a long enough period of time (usually 18 hours or more) to allow spores to germinate and infect the grasses; optimum range of temperature; nutrient levels; mowing in general, which opens the grass to pathogens, and mowing too short for the grass species; insufficient aeration; excessive thatch buildup; frequent applications of insecticides, herbicides, and even fungicides (thatch decomposition is reduced due to the absence or low level of earthworms and decomposing microorganisms).

Most turf disease fungi live in the soil and thatch layer and feed off of living or dead plant or animal matter. Most of these fungi produce spores, sclerotia, or stromata that are spread by wind, water, or mechanically and then grow and multiply into mycelia. The diseases break down plant tissues to the point that the tissues are unable to function normally. More spores or other reproductive parts are produced and the cycle continues.

The critical role of healthy turf and soil in minimizing the occurrence and severity of turf diseases is increasingly becoming better understood and practices that create overall soil health are being more commonly applied for this reason, especially in regards to golf course turf management.

Brown Patch

Target/Host
Bentgrass, bluegrass, fescue, ryegrass, bermudagrass, and zoysia. Bluegrass shows a higher degree of recovery due to its underground rhizomes.

Potential Indirect Treatment Strategies

Cultural Management

Irrigate in the early morning to minimize wet grass at night and infrequently but deeply during hot weather. Follow a good turfgrass cultural program. Avoid mowing too low for the species (often not feasible in golf course situations). Fertility management is very important. Avoid high levels of nitrogen and low levels of phosphorous, potassium, and calcium. Do not allow excessive thatch buildup. Poor drainage substantially increases the severity of the disease. Dew is thought to play a major role in the development of the disease; poling, syringing, and other dew removal techniques and the use of hydrated lime can substantially reduce brown patch. Overseed with disease-resistant varieties as appropriate to site and use conditions and existing species planted. (See "Design and Construction" below for grass varieties resistant to brown patch.)

Habitat Modification

See "Cultural Management" above. Where practical, soil solarization of diseased areas at temperatures of 45-50C to a depth of 10 cm will destroy the disease while leaving many beneficial organisms unharmed.

Design and Construction

Use disease-resistant varieties when appropriate to site and use conditions. Grass varieties reported to be resistant to brown patch are: perennial ryegrass - All Star, Barry, Citation, Delray, Manhattan II, Palmer, Pennant, Prelude, Premier, Yorktown II; tall fescue - Brookston, Jaguar, Mustang, Olympic.

Proper construction of the soil base is important to ensure good drainage, air interchange, and overall soil health.

Biological

Research has indicated that soil inoculation of Trichoderma may slow or prevent the development of brown patch. An organic soil amendment called Dis-Patch has been developed specifically for brown patch. Field trials of these materials may be useful in determining their effectiveness.

Chemical

Many conventional fungicides are available for control of this disease. Neem oil used as a soil drench has shown some promise in inhibiting the growth of various diseases, including Rhizoctonia, but is not yet registered for use as a fungicide. Fungicidal soap (e.g., Safer Natural Garden Fungicide) is a new product and may become a useful tool for control of brown patch in the future.

Dollar Spot

Target/Host
Most turfgrasses, especially bentgrasses.

Potential Indirect Treatment Strategies

Cultural Management

Avoid calcium deficiency and excessive alkalinity. Highly soluble nitrogen fertilizers should not be used just before and during warm weather. Provide a proper balance of soil nutrients, especially nitrogen. Removal of dew on golf courses in the early morning reduces the severity of the disease. Provide adequate drainage hrough aeration, topdressing, and other soil structure improvement methods. Irrigate early in the morning so grass can dry out before nightfall and during warm weather irrigate infrequently but deeply. Especially avoid puddling. Do not allow excessive thatch buildup. Infected grass clippings should be removed to help prevent further spread of the disease. Overseed with disease-resistant varieties as appropriate to site and use conditions and existing species planted. (See "Initial Design" below for grass varieties resistant to dollar spot.

Habitat Modification

See "Cultural Management" above. Where practical, soil solarization of diseased areas at temperatures of 45-50C to a depth of 10 cm will destroy the disease while leaving many beneficial organisms unharmed.

Design and Construction

Proper construction of the soil base is important to ensure good drainage, air interchange and overall soil health.

Use disease-resistant species and varieties when appropriate to site and use conditions. Tall fescue in general is less susceptible to dollar spot. Grass varieties reported to be resistant to dollar spot are: fine fescue - Agram, Barfalla, Biljart, Checker, Encota, Famosa, Koket, Reliant, Scaldis, Shadow, Tournament; Kentucky bluegrass - Adelphi, America, Aquila, Arista, Bonnieblue, Bristol, Eclipse, Galaxy, Geary, Majestic, Midnight, Newport, Palouse, Parade, Park, Pennstar, Prato, Primo, Sodco, Windsor; perennial ryegrass - Barry, Capper, Caravelle, Citation, Dasher, Ensporta, Exponent, Linn, Manhattan II, NK-100, NK-200, Regal, Rex, Sprinter, Venlona.

Biological

Research has indicated that soil inoculation of Trichoderma may slow or prevent the development of dollar spot. Organic soil amendments that have been enhanced with beneficial microorganisms show promise in preventing or arresting the disease. Field trials of these materials may be useful in determining their effectiveness.

Chemical

Experiments of drenching with a household bleach solution of 1 oz. bleach per 4 gallons of water have shown reduction, but not elimination, of the disease. Neem oil used as a soil drench has shown some promise in inhibiting the growth of the disease but is not registered for use as a fungicide. Fungicidal soap may also become a useful tool for control of dollar spot. Many conventional fungicides are available.

Fusarium Blight

Target/Host
Colonial and creeping bentgrass, bluegrass, fine fescue. Severe on bluegrass and fescue mixes.

Potential Indirect Treatment Strategies

Design and Construction

Proper construction of the soil base is important to ensure good drainage, air interchange and overall soil health. Use disease-resistant varieties when appropriate to site and use conditions. Grass varieties reported to be resistant to fusarium blight are: Kentucky bluegrass - Columbia. Adelphi and A-20 are less susceptible than Merion and Touchdown. Kentucky bluegrass mixes that include 10-15% by weight perennial ryegrass also show resistance.

Cultural Management

Overseed perennial ryegrass and tall fescue into susceptible bluegrasses. Fall nitrogen fertilization and biologically active soil conditioners (e.g., Ringer's Lawn Restore) aid in recovery. Fusarium blight seems more prevalent on drought-stress turf.

Chemical

Fenarimol or iprodine in conjunction with the application of nitrogen.

Fusarium Patch (Pink Snow Mold)

Target/Host
Most cool season grasses including perennial ryegrass, creeping bentgrass, fescues, and bluegrass.

Potential Indirect Treatment Strategies

Cultural Management

Avoid excessive application of nitrogen in the fall to prevent the turf from actively growing as cold weather approaches. Adequate drainage is important; fall aeration aids soil drainage through the winter. Avoid thatch buildup, especially in the fall. Remove grass clippings and mow at normal height during the last mowing of the season. "Adequate levels of potash and low pH seem to suppress the disease." (Decker) Overseed with disease-resistant varieties as appropriate to site conditions and existing species planted. (See "Design and Construction" below for grass varieties resistant to fusarium patch.)

Design and Construction

Proper construction of the soil base is important to ensure good drainage, air interchange and overall soil health. Use disease-resistant varieties when appropriate to site and use conditions. Grass varieties reported to be resistant to fusarium patch are: fine fescue - Barfalla, Biljart, Jade, Jamestown, Koket, Scaldis; Kentucky bluegrass - Adelphi, Admiral, Apex, Birka, Bonnieblue, Classic, Destiny, Fylking, Glade, Julia, Lovegreen, Monopoly, Nassau, Ram I, Shasta, Victa; perennial ryegrass - All*Star, Barenza, Birdie II, Blazer, Cockade, Cowboy, Diplomat, Eton, Fiesta, Game, Gator, Lamora, Manhattan, NK-200, Norlea, Omega, Palmer, Pelo, Pennant, Prelude, Premier, Repel, Regal, Sprinter, Tara, Wendy, Yorktown II.

Biological

Research has indicated that soil inoculation of Trichoderma may slow or prevent the development of fusarium patch.

Chemical

Many conventional fungicides are available for control of this disease. Iron sulfate solutions may be used to drench areas where snow mold is a problem. (Mix 14 g ferrous iron sulfate per gallon of water and the solution must be used immediately because it only takes a half hour for the mixture to change into an ineffective form.) Neem oil used as a soil drench has shown some promise in inhibiting the growth of various diseases but is not registered for use as a fungicide. Fungicidal soap (e.g., Safer Natural Garden Fungicide) is a new product and may become a useful tool for control of brown patch in the future.

Gray Snow Mold (Typhula Blight)

Target/Host
Most cool season grasses, including fescues, ryegrass, and bluegrass.

Potential Indirect Treatment Strategies

Forces of Nature

Increasing temperatures and decreasing moisture conditions quickly arrest the disease.

Cultural Management

Avoid excessive application of nitrogen in the fall to prevent the turf from actively growing as cold weather approaches. Fall aeration aids soil drainage through the winter. Avoid thatch buildup, especially in the fall and remove grass clippings during the last mowing of the season.

Design and Construction

Proper construction of the soil base is important to ensure good drainage, air interchange and overall soil health.

Biological

Research has indicated that soil inoculation of Trichoderma may slow or prevent the development of gray snow mold.

Chemical

Many conventional fungicides are available for control of this disease. Iron sulfate solutions may be used to drench areas where snow mold is a problem. (Mix 14 g ferrous iron sulfate per gallon of water and the solution must be used immediately because it only takes a half hour for the mixture to change into an ineffective form.) Neem oil used as a soil drench has shown some promise in inhibiting the growth of various diseases but is not registered for use as a fungicide. Fungicidal soap (e.g., Safer Natural Garden Fungicide) is a new product and may become a useful tool in the future.

Red Thread

Target/Host
Perennial ryegrass, red fescue, Kentucky bluegrass, colonial bentgrass, creeping bentgrass, velvet bentgrass, annual bluegrass, and bermudagrass are most susceptible.

Potential Indirect Treatment Strategies

Cultural Management

Supply adequate levels of nitrogen as well as balanced overall soil fertility. "Red thread is most severe where potassium, phosphorous, calcium, and especially nitrogen are deficient. Avoid overstimulation with fertilizer, particularly with a quickly available, high nitrogen product." (Shurtleff et al.) Infected leaf tips are removed by regular mowing which lessens severity of the disease. Regular, deep irrigation tends to make turf less susceptible. Maintain soil pH between 6.5 and 7.0. Overseeding with hard fescues is common where red thread is a serious problem.

Design and Construction

Use disease-resistant varieties when appropriate to site and use conditions. Grass varieties reported to be resistant to red thread are: fine fescue - Argenta, Aurora, Banner, Barfalla, Bighorn, Biljart, Cascade, Center, Centurion, Engina, Ensilva, Epsom, Fortress, Gracia, Grello, Highlight, Ivalo, Jade, Logro, Magenta, Mary, Pennlawn, Puma, Ranier, Reliant, Ruby, Scaldis, Scarlet, Sparta, SR 3000, Tamara, Valda, Veni, Victory, Waldina, Waldorf, Weekend, Wintergreen; Kentucky bluegrass - Adelphi, Admiral, Arista, Birka, Bonnieblue, Bristol, Campus, Cello, Challenger, Cougar, Delta, Dormie, Eclipse, Geary, Georgetown, Majestic, Monopoly, Nassau, Newport, Palouse, Primo, Sodco, Touchdown, Trenton; perennial ryegrass - Barenza, Birdie, Blazer, Clipper, Commander, Competitor, Ensporta, Eton, Exponent, Lamora, NK-100, NK-200, Norlea, Perma, Player, Regency, Score, Sprinter, SR 4000, SR 4100, Venlona, Wendy.

Proper construction of the soil base is important to ensure good drainage, air interchange and overall soil health.

Chemical

Many fungicides are labeled for control of red thread. No other direct control measures are available.

Take-all Patch

Unlike brown patch, take-all disease patches recur in the same location year after year, enlarging with each successive year by about 15 cm until they reach a diameter of over 1 meter. The disease is particularly prevalent on wet, poorly drained, and unbalanced pH soils, and sand putting greens.

Target/Host
Bentgrass, bluegrasses, ryegrasses, red and tall fescues.

Potential Indirect Treatment Strategies

Cultural Management

Remove diseased patches and re-sod. Regrade soil where water ponding is a problem. Provide good drainage and irrigation practices. Incorporate 3-4 pounds of actual elemental sulfur per 1,000 square feet into the top several inches of soil before reseeding. Balanced soil fertility is important; fertilizer types and formulas should be selected based on soil testing. "Avoid overliming. Apply lime only when absolutely needed on bentgrasses (pH below about 5.0), using a slowly dissolving type (100 mesh or coarser). For fertilizer, use ammonium sulfate, monoammonium phosphate, ammonium chloride, muriate of potash (KCL), or other sulfur-bearing material containing nitrogen to maintain the pH at 5.5 or slightly below. Three to five pounds per 1,000 square feet of actual elemental sulfur in several split applications is often recommended for each growing season where take-all patch is a serious problem." (Shurtleff, et al.) Avoid excessive thatch buildup. "Take-all patch is often more severe where thatch has built up and the soil has been fumigated. This is probably due to the killing off of organisms antagonistic or parasitic on the take-all fungus." (Shurtleff, et al.)

Design and Construction

'Putter' creeping bentgrass is resistant to take-all patch, however, reportedly may not provide a sufficient quality turf.

Proper construction of the soil base is important to ensure good drainage, air interchange and overall soil health.

Chemical

Rovral and Easout fungicides have shown effectiveness in treating infestations. "Applications of ammonium sulfate or sulfur to lower the soil pH have been the most effective means of reducing the severity of this disease." (Turgeon)

Turf Anthracnose

Target/Host
Most severe on annual bluegrass. Various strains appear to be quite host specific; sometimes attacking only one of the susceptible species present.

Potential Indirect Treatment Strategies

Cultural Management

Avoid overfertilization, especially during hot, dry periods. Ensure adequate nitrogen, phosphorous, and potassium. Provide deep, morning irrigation.

Design and Construction

Proper construction of the soil base is important to ensure good drainage, air interchange and overall soil health.

Use disease-resistant varieties when appropriate to site and use conditions. Grass varieties reported to be resistant to red thread are: creeping bentgrass - some strains are highly resistant or even immune; hard fescue - Aurora, Reliant, Spartan, Waldina.

Chemical

Several fungicides are labeled for control of turf anthracnose. No other direct control measures are available.

Source: IPM Access - An Integrated Pest Management Online Service

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URL: http://www.efn.org/~ipmpa
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