PYrenophora triticirepentis as a component of the fungal flora of winter wheat seed in New York

Abstract

The occurrence of P. tritici-repentis among the fungal flora of soft white winter wheat seed in New York, USA, was assessed during 1990-91. The fungus was recovered from 54% of the seed lots in 1990 and from 36% of the seed lots in 1991, infecting an av. of 2.1 and 0.6% of the seeds, respectively. Seed infection by fungal pathogens was generally low in 1991. Alternaria spp. were the fungi most commonly associated with soft white winter wheat seed in both years. Stagonospora [Leptosphaeria] nodorum, Epicoccum nigrum and various Fusarium spp. were also prevalent, particularly in 1990. Mycelium of P. tritici-repentis was detected by culturing and light microscopy in all layers of the pericarp of the wheat seed, but not in the seed coat or the embryo. Surface infestation of the seed by conidia and conidiophores was minimal.