Key Number 1, Fungal Hyphae

Hyphae without cross wall (septa)

• (Pythium spp.)

Hyphae with cross wall (septa)

• Hyphae branched at right angles, with constrictions at branch origins; uniform hyphal diameter

  (Rhizoctonia spp.)

• Hyphae branch in Y's; non-uniform hyphal diameter
  (Sclerotinia spp.)

  *useful only to distinguish from Rhizoctonia spp.

• Hyphae with clamp connections

  (Typhula spp.)

  *look for small, dark sclerotia embedded in infected tissue

  (Limonomyces roseipellis)

  *Look for cottony pink mycellium on infected patches of turf)

• (Basidiomycetes) Most of the fairy ring fungi

  *Look for white mycellium in the soil or thatch at the outer edge of rings