Several trypanosomatids (Protozoa, Kinetoplastida) can be found in plants. Some are localized in the phloem and are associated with a wilt, some live in latex vessels and other occur in fruits. Fruits can suffer local damages. But in most cases trypanosomatids do not cause any symptom in latex plant. All have similar morphology, and ultrastructure and are put in an arbitrary genus Phytomonas. Insects - Hemiptera of the families Lygaeidae, Coreidae, Pentatomidae - propagate these organisms. Under this apparent uniformity, a large diversity and variabilty is found when using sequences analyses of different target genes. The study of 5S rRNA gene shows that if phloem restricted trypanosomatids form one unique defined group - transmitted exclusively by pentatomid bugs - fruits and latex isolates are not always distinct. Alignment of sequences of the ribosomal operon including the two Internal Transcribed Spacer (ITS) and analyses of microsatellites included in the ITS confirm the diversity. Inside one well defined group as the phloem one, the SL RNA gene can distinguish two robust subgroups. All molecular informations obtained so far match biological and epidemiological data. Correspondances to taxomic levels are under study. (Texte intégral)