Abstract
A new non-native species of sawfly Nematus lipovskyi Smith, 1974, previously known only in the USA, has heavily infested the ornamental azalea plant, Rhododendron molle, in the Czech Republic since at least 2010. The data on this species in the USA is briefly summarized.
The larva and hitherto unknown male are newly described and illustrated. The life cycle is described based on field observations and the rearing of larvae collected in Charles University Botanic Garden in Prague.
The host plants are listed and include the first record of a European species of azalea (Rhododendron luteum). The current distribution of Nematus lipovskyi in the Czech Republic based on the results of a preliminary monitoring project carried out by Charles University in Prague and the State Phytosanitary Administration is presented.
The pathways of its introduction and spread, potential phytosanitary measures and its effect on the environment are briefly discussed.