The Taxonomy of "Helminthosporium" Species

Abstract

Helminthosporium Link: Fr. is a generic name well known to plant pathologists.l It has been applied to some important pathogens, such as H. maydis Nisik. & Miyake, H. oryzae Breda de Haan, H. turcicum Pass. and H. teres Sacco These and similar species are commonly associated with leaf spots or blights, foot rots, and other disease syndromes on cultivated and wild Poaceae. Their ability to cause devastating disease has occasionally resulted in famine and loss of human life (82) or in great economic loss (121). Other plant groups are also affected: palms (27), cacti (13), Leucospermum spp. (123), beans (29), forage legumes (93), rubber, Musa (24), and coffee (l 05) are reported as hosts. In addition, mycoses in domestic animals and man increasingly are being attributed to these fungi (70). They have been im­ plicated in mycotoxicoses in grazing animals (97), and mycoparasitic activity by them has been reported (83). Their classification is therefore of more than academic interest, especially as the genus Helminthosporium should be re­ stricted to ca. 20 species (34), most of which are saprotrophs. It has been suggested that knowledge of the systematics of two segregate genera, Drech­ slera and Bipolaris, is inadequate (33). The subject of this review is the taxonomic and nomenclatural fate of the predominantly graminicolous species studied by plant pathologists and others.