SUMMARYTwo main types of canker on the shoulders and crowns of parsnips are described, (a) black canker, caused byItersoniliaorPhoma, or both together, and (b) orange‐brown canker, of unknown cause. Black canker is the more common.A large number of isolates ofItersoniliawere obtained from diseased parsnip roots and leaves and from the air within parsnip crops in widely separated localities. The dicaryophase only of these isolates was studied. The majority possessed many chlamydospores and agreed with the descriptions by Olive and by Sowell&Korf of isolates obtained from and pathogenic to parsnips. Although these authors identified such isolates as I.perplexans, the writer considers that they should be regarded as a new species, I.pastinacae.The remainder of the isolates from these sources and a number from other hosts possessed few or no chlamydospores and more closely resembled I.perplexansDerx. Tests showed that I.pastinacaewas pathogenic to parsnip roots and leaves, but not to chrystanthemum flowers, while an isolate of I.perplexanspathogenic to chrysanthemums, did not attack parsnips. Of the other isolates resembling I.perplexans, only those obtained from cankered roots were pathogenic to parsnip roots.APhomasp. causing black canker was isolated from parsnips in four out of thirteen localities. In laboratory pathogenicity tests it attacked only parsnips (both seedlings and mature roots), and may thus be different from otherPhomaspp. Parsnip foliage was readily infected artificially, but natural leaf infection has not been observed in the field.Attack by both I.pastinacaeandPhomasp. was enhanced by wounding of the parsnip root