Hoary cresses (Cardaria spp., Brassicaceae) are deep-rooted, perennial mustards of European origin that were introduced into the United States during the late 19th century. Since then, they have spread thoughout the western and the northeastern states, invading crops, rangelands and riparian areas, and are presently declared noxious weeds in 14 U.S. states and three Canadian provinces. Because conventional methods do not lead to satisfactory control of hoary cresses, a biological control project was initiated in spring 2001. Since the beginning of May, nearly 100 sites in 10 countries (i.e. Armenia, Austria, Denmark, France, Germany, Hungary, Rumania, Russia, Switzerland, and Turkey) were sampled to obtain an overview of the herbivores associated with Cardaria spp. in its native range. The majority of adult insects collected were flea beetles (e.g. Phyllotreta spp.) and weevils (e.g. Ceutorhynchus spp.). Plants at most sites showed signs of external and/or internal damage, and all plant parts (roots, shoots, leaves, flowers, seeds) were found to be attacked. Of the herbivores determined so far, the four weevil species, Ceutorhynchus cardariae Korotyaev, C. merkli Korotyaev, C. turbatus Schultze, and Baris semistriata Boheman (Col., Curculionidae) are considered promising biocontrol agents, due to records of their restricted host range. More detailed investigations are planned with these species in 2002. Similar surveys have been started in Idaho to determine which herbivores attack hoary cresses in North America. In addition, comparative studies on the ecology of the plant were initiated in Europe and North America to elucidate factors responsible for the success in its new range.
Species 1: Brassicaceae Cardaria spp (hoary cress, whitetop)
Keywords: Mustard weeds, biological weed control
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA