Observations on the growth of Lycoperdon perlatum associated with fairy ring disease of turfgrass

Summary

Fairy ring disease of turfgrass is a recurring problem in Georgia. Results of laboratory experiments reveal that Lycoperdon perlatum, a cause of fairy ring, is a weak competitor, an uncharacteristic trait of a successful soil-invading fungus. However, we postulate that a tolerance to high temperature allows L. perlatum to inhabit a microbial suppressive niche in turfgass soils (e.g. a zone associated with high temperature and/or low water potential).

Situation

Based on reports from turfgrass managers in Georgia, the incidence and severity of fairy ring disease of warm- and cool-season grasses appears to be on the rise. Symptoms range from stimulation of leaf growth and color, occurring in patches, arcs or rings in turfgrass swards, to complete foliar desiccation and necrosis of affected turf. In addition, irregular shaped 'localized dry spots' have been observed inside stimulated fairy rings. Symptoms appear to be quite common in Georgia on lawns, athletic fields and golf courses infested with the fungus Lycoperdon perlatum.

Response

Review of the mycological research literature revealed that, beyond several taxonomic and genetic studies, there are few reports covering the biology and ecology of Lycoperdon species, particularly with reference to turfgrasses and fairy rings. Therefore, a series of experiments were conducted at the University of Georgia Griffin Campus on the physiology and growth of L. perlatum associated with fairy rings of turfgrasses in Georgia. To determine the effect of temperature on growth of L. perlatum, an isolate (2012-1A) obtained from a basidiocarp associated with fairy ring symptoms on a creeping bentgrass golf green, was incubated on yeast-malt agar in petri dishes exposed to temperatures ranging from 4 to 40 C. In addition, isolate 2012-1A was paired with isolates of fungi including Magnaporthe, Pyricularia, Rhizoctonia, Sclerotinia, Colletotrichum and Sclerotium on yeast malt agar to assess interactions between L. perlatum and other fungi associated with creeping bentrgrass.

Impact

Mycelial growth of isolate 2012-1A was detected at all temperatures tested, except 40 C. The most rapid growth occurred at 32 C after 1 and 2 weeks of incubation, and at 28 C after 3 weeks. After 3 weeks incubation, a decline in radial growth, observed between 28 and 38 C, was less than 30%, suggesting a tolerance to high temperatures. After 3 weeks growth at 25 C, interactions between isolate 2012-1A and other fungal species were classified as either deadlock (colony contact with no evidence of inhibition or growth of one colony into the zone of the other) or replacement (overgrowth of one colony by another). The results indicate that L. perlatum is a fungus that tolerates high temperatures (>28 C), does not produce antifungal compounds, and it is non-combative (i.e. it does not overgrow or parasitize mycelium) when challenged by other fungi. These observations suggest that L. perlatum is a weak competitor, an uncharacteristic trait of a successful soil-invading fungus. However, it is possible that L. perlatum avoids competition by inhabiting a microbial suppressive niche (e.g. an ecological zone defined by high soil temperature and/or low water potential). These findings enhance our understanding of L.perlatum and fairy ring disease in Georgia, and other states and regions.

State Issue

Agricultural Profitability and Sustainability

Details

• Year: 2013
• Geographic Scope: Multi-State/Regional
• County: Spalding
• Program Areas:
  • Agriculture & Natural Resources