Strains ofStemphylium vesicarium(Wallr.) Simmons, were collected from asparagus plants (Asparagus qfficinalisL.) from different regions of New Zealand. The pathogenic variation among five strains was compared in glasshouse tests using eightAsparagustaxa (six resistant spp. and two susceptible cultivars ofA. officinalis, ‘Rutgers Beacon’ and ‘Mary Washington’). Disease assessments, based on percentage stem area necrosis, were made 10–14 days after inoculation. Disease severity (% stem area necrosis) for different strain/taxa interactions, after inoculation, ranged from 0 to 55%. One of the isolates tested was found to be a saprophytic strain ofS. vesicarium. Differences in pathogenicity (P< 0.05) among strains were found.Stemphyliumstrain/Asparagustaxa interactions were highly significant (P< 0.001). Three highly resistant taxa ofAsparagus—A. virgatusBak.,A. lar cinusBurch.,andA. compactusSailers—are useful sources for breeding for resistance toStemphyliumleaf spot on asparagus.