From ISTA 7-027 method using omsotic method (growth on filter paper moistened with sugar solution):
On blotter paper, P. teres cannot be distinguished from P. graminea, as both produce the same pigment - catenarin. The infected seeds produce brick-red pigements (anthraquinones) under certain conditions (correct temperature, bright light and adequate moisture). When a wehat solution of NaOH is added, the pigments will turn from brick-red to violet.
From ISTA Common Laboratory Seed Health Testing Methods for Detecting Fungi:
Conidiophores dark brown to blackish, medium to long, arising singly in most cases, straight, with lighter, cylindric conidia at tips. Conidia 1 to 3, acropleurogenously arranged on conidiophores. In some cases secondary conidiophores can bear more conidia. Pycnidia with stiff setae may develop on tehs seed surface.
Conidia smooth walled, light brown, straight, cylindrical, basal cell in some cases longer than wide, 3-5 distoseptate, 32-100 x 14-19 μm.
