lˈæktuːkə sˌɛɹɪˈoʊlə ɪz ðə wˈaɪld pɹoʊdʒˈɛnɪɾɚɹ ʌv kˈʌltᵻvˌeɪɾᵻd lˈɛɾɪs lˈæktuːkə sˈæɾɪvə, ænd kæn biː ɐfˈɛktᵻd baɪ lˈɛɾɪs dˈaʊni mˈɪldjuː, wˈʌn ʌvðə mˈoʊst sˈɪɹiəs dɪzˈiːzᵻz ʌv lˈɛɾɪs.
Lactuca serriola is the wild progenitor of cultivated lettuce (Lactuca sativa), and can be affected by lettuce downy mildew, one of the most serious diseases of lettuce.