Grape phylloxera (Daktulosphaira vitifoliae Fitch) in Argentina: ecological associations to diversity, population structure and reproductive mode

Background and AimsThe North American insect pest grape phylloxera was introduced into Europe in the 19th century and devastated the Vitis vinifera-based vineyards. It has since become widely distributed among the world's vineyards. Although it is present in Argentina, it has not caused any major damage. This work aims: to characterise the genetic diversity of Argentinean phylloxera; to determine population structure and reproductive mode; to compare Argentinean genotypes with samples from seven other countries; and to examine relationships between the infestation level and genetic profile with ecological factors. Methods and ResultsOne hundred and twenty-nine samples of phylloxera from Argentinean provinces were analysed with 21 microsatellite markers. Seventeen multilocus genotypes were identified. Unweighted pair group method with arithmetic mean analysis identified two major groups. Principal coordinates analysis grouped together Peruvian, California biotypes A and B and Argentinean phylloxera, showing dissimilarity with other foreign samples. Associations between infestation level, berry colour and climatic region, and associations between genetic clusters and climatic region were established. ConclusionsEndemic Argentinean phylloxera genotypes showed genetic diversity and were different from other samples assessed. Parthenogenesis is proposed as the main reproductive mode, but rare sexual reproduction is not ruled out. No particular structure was observed in the phylloxera populations. Significance of the StudyThis is the first detailed report on the genetic characterisation of phylloxera populations in Argentina using microsatellites markers. It provides the foundation for further studies.