ðiːz tˈɜːmz ɐplˈaɪ wɛn tˈuː hˈoʊsts ɑːɹ ɹᵻkwˈaɪɚd baɪ ɐ hˌɛɾɚɹəˈɛʃəs ɹˈʌst fˈʌŋɡəs tə kəmplˈiːt ɪts lˈaɪf sˈaɪkəl.
These terms apply when two hosts are required by a heteroecious rust fungus to complete its life cycle.