Anthracnose Disease

Scientific name: Colletotrichum cereale

Identification

The grass turns a sickly yellow and orangey/brown colour, with the basal rotting away. The youngest leaf has also been reported as sometimes turning a reddish colour. Minute black structures (acervuli) can often be seen at the base of the grass.

Anthracnose can be observed throughout the year, but it is more prominent when the grass is growing slowly.

In the USA anthracnose is separated into two types, although it has been reported as such in the UK:

  1. Anthracnose foliar blight, which affects the outer leaf tips and gradually works inwards. If left untreated this can advance to basal rot.
  2. Anthracnose basal rot, which destroys the base of the grass making it easy to pull out of the sward. The foliage is affected after the basal rot has commenced. This is much more serious than foliar blight.

Main grasses affected

Annual meadow grass: Poa annua is susceptible to both foliar blight and basal rot.

In the UK bentgrasses and perennial ryegrass can be affected by foliar blight, however, in these species it causes a thinning of the sward, with darker lower leaves and yellowy/light brown upper leaves and is of only minor consideration.

Conditions favourable to the disease

  • Compacted turf
  • Increased plant stress due to more usage and intensive maintenance;
  • Low nitrogen levels;
  • Humid weather - warm and cool;
  • Thatchy, moisture retentive turf;
  • Poorly drained rootzone;
  • Low mowing heights causing undue plant stress;
  • Poorly set mowers and blunt blades.

Control measures

  • Keep the soil well aerated;
  • Move golf pin positions more regularly;
  • Spread wear for entry and exit points on golf and bowling greens;
  • Improve the drainage system.
  • Reduce thatch layers - both depth and density of them;
  • Box off and remove clippings;
  • Improve air circulation around the area: Consider thinning hedges, trees etc., removing overhanging branches;
  • Reduce Poa annua content of a sward;
  • Provide a more acidic soil to discourage annual meadow grass;
  • Use sulphate of iron on a regular basis to promote surface acidity;
  • Set mower correctly and ensure the blades are sharp;
  • Apply a nitrogen fertiliser, although not much later than August on golf and bowling greens;
  • Ensure soil potassium levels are appropriate, especially if the turf appears stressed during the summer period.
  • Manage usage. If soil conditions are unsuitable, then postpone play.

Notes

This was first reported in the UK in 1953 on a cricket square, however, a possible recording may have been as early as in 1936.

In the UK, 1987 and 1992 were reported as being particularly bad years for anthracnose attacks.

This disease is a good indicator of poor environmental conditions for the grass plant. A review of the management and maintenance plan should ideally be carried out following such an attack.

Whilst following a regime of stressing annual meadow grass to encourage an increase in the fescue/bentgrass content, the likelihood of anthracnose attacking the sward might be increased.

References

Anon, 'Current disease problems on fine turf', Sports Turf Bulletin No. 143, STRI, October - December 1983, 3-5

Anon, 'Enquiries and Replies - Anthracnose', Journal of the Sports Turf Research Institute, 1994, 143-144;

Baldwin, N., 'Turf Disease Notes - Brown Patch and Anthracnose', Sports Turf Bulletin No.163, STRI, October-December 1988, 4-5;

Baldwin, N., 'Turf Disease Notes 1987', Journal of the Sports Turf Research Institute, 1988, 183-184;

Baldwin, N.A., Turfgrass Pests and Diseases, Third Edition, STRI, 1990;

Baldwin, N. 'Turfgrass Diseases in Winter', Greenkeeper International, January/February 1991, 37-39;

Hall, J., 'Coping with growth of turf disease', The Groundsman, September 1999, 23;

Stansfield, D., 'Yellow Peril', Turf Management, January 1993, 10;

York, C.A., 'Anthracnose - Basal Rot and Foliar Blight', Sports Turf Bulletin No.183, STRI, October-December 1993, 12;