Recorded by Latch as the second most important foliage disease of ryegrass in New Zealand; it occurs throughout the country in long dense swards and in short pastures, especially in winter months.

In group VIII, D. andersenii and D. dictyoides were sister species with strong bootstrap support from the three data sets. These two species have a complex history. Drechslera dictyoides was first described from the United States on meadow fescue by Drechsler (1923). Braverman and Graham (1960) described two forms: D. dictyoidesf. sp. dictyoideson fescues and D. dictyoidesf. sp. perennis on ryegrass. Using numerical taxonomic methods, the two forms of D. dictyoides were confirmed by Ibrahim and Threlfall (1966), but were not thought worthy of specific rank. On the other hand, Scharif (1959) found that the most common species of Drechslera on ryegrass was different from D. dictyoidesfound on meadow fescue and described it as D. andersenii, but without a Latin diagnosis. Based on the results of Scharif (1959), D. andersenii was identified by Ellis (Commonweath Mycological Institute), but not validated as species. Lam and Chapman (1985), using numerical taxonomic methods, found that the form of D. dictyoides occurring on ryegrass was worthy of rank at species level. Thus, D. andersenii was separated and this taxon is currently accepted as a valid species (Lam 1985). From the history of D. andersenii, it is evident that D. dictyoidesand D. andersenii have a very close relationship. These observations are confirmed by the data obtained in the present study.