Leptosphaerulina Blight

  Leptosphaerulina  spores (extension.umaine.edu).  

Leptosphaerulina spores (extension.umaine.edu).  

      Though it can appear anytime between spring and fall, Leptosphaerulina (pronounced "Lep-toe-sphere-u-line-a") thrives in stressed turf under conditions such as extended warm, humid weather. Considered a senectopathic disorder (like anthracnose), it can be classified as a pathogen when infecting young and mature plants. Commonly found in association with Pythium spp. and Pysularia grisea, symptoms of leptosphaerulina blight include uniform yellow or brown spots extending down the sheath, with stands being either uniformly blighted or patchy with individual leaves dying back from the tip.² Affected stands may also show significant thinning in as little as a week.  

 Psuedothecia visible on an alfalfa leaf (insectimages.org).

Psuedothecia visible on an alfalfa leaf (insectimages.org).

     A common soil saprophyte, leptosphaerulina thrives in rotten material, producing pseudothecia in leaf-tissue in order to overwinter. Coming from ancient Greek-  literally meaning "false-sheath"-  pseudothecia are volcano-shaped structures which become embedded in the tissue, where they house fungal spores (ascopores, see image above). Released when warm weather returns, the ascopores are then blow, splashed or carried via equipment to healthy turf.  

     While modern cultural practices on golf courses may be contributing to its increased appearance in otherwise healthy turf (lower mowing heights, verticutting, etc.), there are some preventative steps for leptosphaerulina.  

  • Avoid irrigating in the evenings or nights 
  • Aerate compacted soil, reduce thatch
  • Use a balanced fertility program

     Check out the links below for more information, and take a look at this recent piece by Dr. Rick Latin, where he goes over different aspects of Leptosphaerulina blight for turf diseases.org.

1. http://agsci.psu.edu/elearning/course-samples/ppem_412_sample/Ln_11/L11_5.htm

2. http://ipm.illinois.edu/diseases/series400/rpd417/

3. Creeping Bentgrass Management: Summer Stresses, Weeds and Selected Maladies