Date of Award:
5-1-1989
Document Type:
Thesis
Degree Name:
Master of Science (MS)
Department:
Biology
Department name when degree awarded
Biology (Entomology)
Committee Chair(s)
Ting H. Hsiao
Committee
Ting H. Hsiao
Committee
D.W. Davis
Committee
S.V. Thomson
Abstract
The effects of Bathyplectes curculionis (Thomson) and Bathyplectes anurus (Thomson) as parasitoids of the western, eastern, and Egyptian alfalfa weevil strains, (Hypera postica) (Gyllenhal) (Coleoptera: curculionidae), and of hybrid weevils from overlapping zones was assessed in laboratory studies. Field studies assessed the effectiveness of B. curculionis on the western and Egyptian weevil strains and on weevils from the western/Egyptian and eastern/western hybrid zones. Laboratory and field studies showed a decreasing trend of B. curculionis effective parasitism from high in northern Utah, where the western strain occurs to intermediate within the western/Egyptian hybrid zone of southern Utah to low in adjacent Nevada, where the Egyptian strain occurs. The reduction in effective parasitism levels was due to encapsulation of B. curculionis eggs. Encapsulation rates were not affected by the rickettsia (Wolbachia postica) present in the western strain. Increases in average encapsulation rates corresponded with the increasing proportions of the Egyptian weevil strain in populations, except at the Mesquite site. The significantly higher encapsulation rates from areas in eastern Colorado compared to northern Utah, where the western strain occurs, indicate the presence of the eastern weevil strain in eastern Colorado. B. anurus eggs were not encapsulated by any weevil strain and, therefore, may potentially be equally effective on all weevil strains. Improvements in parasitoid use for the biological control of the alfalfa weevil in the western states are discussed.
Recommended Citation
Maund, Christopher M., "Evaluation of the Effectiveness of Two Bathyplectes Parasitoids Among Alfalfa Weevil Strains, (Hypera postica (Gyllenhal))" (1989). Biology. 567.
https://digitalcommons.usu.edu/etd_biology/567
Copyright for this work is retained by the student. If you have any questions regarding the inclusion of this work in the Digital Commons, please email us at .