His studies of what has since been known as juniper-pear rust showed that this fungus annually switches between two hosts; Juniperus sabina is the primary (telial) host and pear, Pyrus communis, is the secondary (aecial) host.
hɪz stˈʌdiz ʌv wʌt hɐz sˈɪns bˌɪn nˈoʊn æz dʒˈuːnɪpɚpˈɛɹ ɹˈʌst ʃˈoʊd ðæt ðɪs fˈʌŋɡəs ˈænjuːəli swˈɪtʃᵻz bᵻtwˌiːn tˈuː hˈoʊsts; dʒˈuːnɪpɚɹəs sɐbˈiːnə ɪz ðə pɹˈaɪmɚɹi tˈɛlɪəl hˈoʊst ænd pˈɛɹ, pˈaɪɹəs kəmjˈuːniz, ɪz ðə sˈɛkəndɚɹi ˈiːʃəl hˈoʊst.