July 7, 2015
Anthracnose Alert!
bygl 1 6-15-10Conditions are nearly ideal for anthracnose to develop and flourish on golf greens. The weather pattern of hot humid days with frequent thunder storms sets the stage for this disease. Calls and samples are coming in from around the state. If you have a history of this disease, have greens that are prone to anthracnose due to the site or condition, or have active anthracnose …. now is the time to take action.  As I have said many times – “this is one of the nastiest diseases a superintendent has to deal with and can be extremely difficult to manage and recover from”. Do not take this disease lightly or with a wait and see how it develops attitude.
Since the last two summers have been relatively mild, anthracnose and especially the basal rotting stage, has been uncommon or easy to manage. With these conditions occurring this early (early June) we are 30 to 60 days ahead of typical basal rot anthracnose conditions. If these weather patterns continue this could be a challenging year.
bygl 2 6-15-10Basal rot anthracnose, Colletotrichum cereale, formerly called C. graminicola, may be a serious problem on Poa annua (annual bluegrass) and at times on creeping bentgrass putting greens. This is often considered one of the most difficult diseases on greens to deal especially once the disease progresses to the basal rot stage and the turfgrass shows signs of thinning. This is especially true when Poa annua develops the disease in early spring or summer. 
The following are some management guide lines:
Mowing issues - this may be the #1 factor that initiates the onset of anthracnose:
  • Minimize ALL mowing stress –avoid scalping or cutting too low, this is often the factor that leads to anthracnose problems.
  • Do not mow when greens are wet (soft and/or spongy) since this leads to scalping or cutting too low.
  • Use solid rollers, grooved rollers usually lead to a lower cut and stressed plants and anthracnose.
  • Raising mowing heights. Research has shown that a 0.015 inch increase in mowing height can result in an improvement of turf health and reduced anthracnose (i.e.: from 0.125 to 0.141inch).
  • Roll greens to smooth the surface and improve mowing quality, may reduce the mowing frequency and possible increase the height of cut.
  • Use walk-behind mowers and reduce mowing frequency (floating head mowers preferred).
Fertility programs – the greens need to be growing to be healthy:
  • Maintain greens with a sound fertility program for healthy turfgrass. (~ 3 lb N / 1000 ft2 / year).
  • Apply 0.1 to 0.125-lb. N/M sq. ft. from ammonium sulfate or urea every 7-14 days. Tank-mix with fungicide applications.
  • Soil and tissue test to insure that adequate essential elements are available and in the plants.
Water management – irrigation, surface drainage & subsurface drainage:
  • Avoid over watering and excessive wet soils and conditions of continuously wet thatch.
  • Syringe to prevent wilt. Avoid extremes in soil moisture. The goal is healthy turfgrass.
  • Improve and/or provide proper drainage to maximize turfgrass health and vigor.
  • Install drainage systems or rebuild greens to correct poor drainage problems.
  • Address compaction problems, excessive thatch, root zone layering, and green design problems.
Grooming, PGR’s & Pest Management - factors that limit turfgrass growth and health:
  • Avoid aggressive grooming operations in hot wet weather that may severely damage the turfgrass.
  • Light to moderate topdressing can be beneficial to protect the crowns and improve growth & health
  • When grooming operations cannot be avoided, apply fungicides tank-mixed with soluble fertilizers prior to grooming, even if anthracnose is not active. 
  • PGRs can be used as an effective tool to maximize health and part of an Integrated Turfgrass Health Management Program. The key point is, do not stop growth but manage healthy growth.
  • Monitor for other problems such as parasitic nematodes, other diseases, insect pests, etc.
Normally do not use a fungicide from the same chemical class in succession, rotate whenever possible. As temperatures increase keep in mind the growth regulating side effects of sterol-inhibiting fungicides. 
If the disease is active; select the high label rate, shortest timing interval, apply in the proper amount of water to place the fungicide where the disease is active and to protect the host. It is usually recommended to rotate penetrant fungicides from the different classes shown: i.e. Thiophanate (CL 3336 or Fungo 50) in the first 7-10 days; followed by a strobilurin (Compass, Heritage, Disarm or Insignia in the second 7-10 days; followed by a sterol-inhibitor (Banner, Bayleton, Eagle, Trinity, Tourney, Chipco Triton, Torque or Rubigan in the third 7-10 days period. Consider including Chipco Signature in this rotation at least once per month. Endorse is an additional penetrant to consider however works best as a preventative fungicide. Contact fungicides are most effective if applied to completely cover the leaf tissue with minimal run-off.  
NOTES: Spray volume recommendations: - systemics (most are upward moving only) 4 – 5 gal/ 1000 sq ft, - contacts and local penetrants 1 - 2 gal/ 1000 sq ft. 
Strobilurin and thiophanate-methyl resistant biotypes of anthracnose have been reported. Select products that are known to work and monitor for fungicide resistance. If possible leave untreated areas as check plots to observe results.                       
PRODUCT:               RATE:                       FAMILY:                  MOBILITY:
                              (oz/1000 sq ft)
- Daconil Ultrex          3.25 - 5.0 oz                Nitrile                    Contact
- Medallion                  0.25 - 0.5 oz              Phenylpyrolle          Contact          
- CL 3336                    4.0 - 6.0 oz                Benzimidazole        Systemic (upward)
- Endorse                     4.0 oz                       Polyoxin                 Local Penetrant          
- Heritage                    0.2 - 0.4 oz                Strobilurin              Systemic (upward)
- Compass                   0.25 oz                      Strobilurin              Local Penetrant
- Insignia                     0.5 - 0.9 oz                Strobilurin              Local Penetrant
- Disarm                      0.18-0.36 oz              Strobilurin               Systemic (upward)
- Banner MAXX        1.0 - 2.0 oz                  SI / DMI                     Systemic (upward)
- Bayleton 50W          0.5 - 1.0 oz                SI / DMI                     Systemic (upward)
- Rubigan 1AS            1.0 - 1.5 oz               SI / DMI                     Systemic (upward)
- Eagle 20EW             0.2 oz                       SI / DMI                     Systemic (upward)
- Trinity                       0.5 - 1.0 oz             SI / DMI                     Systemic (upward)
- Tourney                     0.28 - 0.37 oz          SI / DMI                     Systemic (upward)
- Chipco Triton            0.15 - 0.3 oz             SI / DMI                     Systemic (upward)
- Torque                       0.6 oz                     SI / DMI                     Systemic (upward)
- Chipco Signature *   4.0   oz                      Phosphite          Systemic (upward & down)
* Other phosphite products have shown reduced anthracnose in some studies.                
Use all fungicides according to the label.
(For more information see the article Anthracnose Management on Greens/Basal Rot Anthracnose by J.W. Rimelspach and M.J. Boehm, Department of Plant Pathology, The Ohio State University.)