Résumé
DNA based methods have revolutionized the field of species diagnostics, and today it has applications for an increasingly number of taxa including several Acari. The media excitement around the international Barcode project is an example. Besides their potential for species identification, DNA marker techniques are nowadays routinely being also used for addressing ecological, evolutionary, phylogenetic and genetic questions. In contrast to other groups of plant mites and despite the economical relevance of many species of Eriophyoidea, very few scientists have dared so far to use DNA methods for the study of this group of mites; their very small size being certainly the major cause. However, DNA]based techniques are now well established and their advantages as well as limitations have been realized. We review here the main techniques used for identification and discus on their applicability in eriophyoids. Main results from the literature will be examined. We will emphasize prospects and challenges of the molecular genetics approach to study several essential issues of the eriophyoid biology to: clarify suspect synonymies, test hypothesis of cryptic species; examine the occurrence of biotypes, especially in rapport to virus ability; understand colonization patterns of invasive species; and use of biological control agents against invasive plants. We will discuss these questions that can be link to economical issues, together with more fundamental aspects as reviewing the phylogeny of the Eriophyoidea. Much is now biology. Eriophyoids should not be the exception