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United States Department of Agriculture

Agricultural Research Service

Title: Rearing and Morphology of the Knapweed Weevil, Cyphocleonus Achates

Authors
item Phipps, Sarah - UNIV OF MO
item Goodman, Cynthia
item Saathoff, Stephen
item Wright Osment, Maureen
item Peters, Paula - UNIV OF MO
item Wagner, Renee

Submitted to: University of Missouri Life Sciences Week
Publication Type: Abstract Only
Publication Acceptance Date: February 18, 2003
Publication Date: March 3, 2003
Citation: PHIPPS, S.J., GOODMAN, C.L., SAATHOFF, S.G., WRIGHT OSMENT, M.M., PETERS, P., WAGNER, R.M. Rearing and Morphology of the Knapweed Weevil, Cyphocleonus achates. UNIVERSITY OF MISSOURI LIFE SCIENCES WEEK. 2003. Available from: http://lsrdb.missouri.edu/cgi-bin/searchsortlsrdb.cgi.

Technical Abstract: The spotted knapweed is an invasive plant species that was introduced into the US in the 1800's and has become established in 46 states. This invasive pest primarily causes problems in the Western States by decreasing the carrying capacity of rangeland by up to 90%. One important means to control invasive pests is through the inoculative release of biological control agents, such as weed-feeding insects. An insect that is known to effectively control spotted knapweed is the weevil Cyphocleonus achates (Coleoptera: Curculionidae). However, low fecundity and variable development times, as well as insufficient knowledge of how this insect interacts with its environment and host plants (i.e., in relation to development, reproduction and diapause), have limited their use both geographically and seasonally. We obtained field populations of C. achates adults and reared them under various combinations of laboratory and greenhouse conditions, using both the host plant as well as meridic diets. We developed improved rearing methods which enabled us to continually produce insects throughout the year, with a reduction in development time and an increase in survivability to adulthood. Additionally, we studied selected morphological features to better understand issues relating to reproduction. The development of a rearing system that continuously produces large numbers of Cyphocleonus achates will increase their availability for release in different geographical areas throughout the U.S. at appropriate times for each region and will increase their availability for biological studies to better understand their interactions with their environment and host plants.

Last Modified: 12/21/2014
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