Track 2-13: Ecology and Control of Vertebrate and Invertebrate Pests of Grass and Forage
Description
The alfalfa weevil Hypera postica (Gyllenhal) (Coleoptera: Curculionidae) is one of the most destructive insect pests of alfalfa herbage in North America. Palearctic in origin, the weevil was first found in North America near Salt Lake City, Utah, in 1902 (Titus 1911), with the first Canadian record in southeast Alberta and southwest Saskatchewan in 1954 (Hobbs et al. 1959; Beirne 1971). Alfalfa weevil became an economic pest on the Canadian prairies only in the area of first location, and its distribution remained below the 51st parallel North latitude for about 40 years. In the mid-1990s, however, the weevil expanded its distribution eastward across southern Saskatchewan and into the neighbouring province of Manitoba (Soroka and Goerzen 2002), where heavy infestations in the last decade caused serious losses to alfalfa hay quantity and quality (Gavloski 2008). Many parasitoids of alfalfa weevil were introduced into North America from Europe in the last century, and the species that established in the eastern half of the continent (Soroka and Otani 2011) have been effective in reducing the impact of the weevil there. The larval parasitoid Bathyplectes curculionis (Thomson) (Hymenoptera: Ichneu-monidae) is the only parasitoid that is well established in western North America, and its distribution on the Canadian prairies is uncertain.
This study was undertaken to determine the distribution of alfalfa weevil in Saskatchewan, Canada, in order to evaluate the potential impact of the pest on the 1.5 million ha of alfalfa and alfalfa/grass hay production in the province. Further, we wished to determine the occurrence of B. curculionis and the possible effect of the parasitoid on the weevil.
Included in
The Occurrence of Alfalfa Weevil and Its Major Parasitoid Bathyplectes curculionis across Saskatchewan, Canada
The alfalfa weevil Hypera postica (Gyllenhal) (Coleoptera: Curculionidae) is one of the most destructive insect pests of alfalfa herbage in North America. Palearctic in origin, the weevil was first found in North America near Salt Lake City, Utah, in 1902 (Titus 1911), with the first Canadian record in southeast Alberta and southwest Saskatchewan in 1954 (Hobbs et al. 1959; Beirne 1971). Alfalfa weevil became an economic pest on the Canadian prairies only in the area of first location, and its distribution remained below the 51st parallel North latitude for about 40 years. In the mid-1990s, however, the weevil expanded its distribution eastward across southern Saskatchewan and into the neighbouring province of Manitoba (Soroka and Goerzen 2002), where heavy infestations in the last decade caused serious losses to alfalfa hay quantity and quality (Gavloski 2008). Many parasitoids of alfalfa weevil were introduced into North America from Europe in the last century, and the species that established in the eastern half of the continent (Soroka and Otani 2011) have been effective in reducing the impact of the weevil there. The larval parasitoid Bathyplectes curculionis (Thomson) (Hymenoptera: Ichneu-monidae) is the only parasitoid that is well established in western North America, and its distribution on the Canadian prairies is uncertain.
This study was undertaken to determine the distribution of alfalfa weevil in Saskatchewan, Canada, in order to evaluate the potential impact of the pest on the 1.5 million ha of alfalfa and alfalfa/grass hay production in the province. Further, we wished to determine the occurrence of B. curculionis and the possible effect of the parasitoid on the weevil.
