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Title: Biological control of Waterhyacinth in the California Delta
Authors: Stewart, R. Michael
Cofrancesco, Alfred F., Jr.
Bezark, Larry G.
Keywords: Aquatic plant control
Aquatic plants
Water beetles
Biological control
California Delta
Aquatic Plant Control Research Program (U.S.)
Publisher: U.S. Army Engineer Waterways Experiment Station
Series/Report no.: Technical Report (Aquatic Plant Control Research Program (U.S.)) ; no.Technical Report A-88-7
Abstract: The purpose of this project was to transfer biocontrol technology developed for waterhyacinth control in the southeastern states to agencies responsible for waterhyacinth control in California. This technology centers on the use of three South American insect species [Neochetina bruchi Hustache and Neochetina eichhorniae Warner (Coleoptera:Curculionidae) and Sameodes albiguttalis Warren (Lepidoptera:Pyralidae)] which effect natural control of waterhyacinth in its native range. The technology transfer consisted of (A.) releasing the biocontrol agents at specific sites in California, (B.) monitoring the establishment of these agents, (C.) evaluating the control effectiveness by these agents, and (D.) monitoring the natural dispersion by these agents. Neochetina bruchi was first released in the Delta in July 1982; N. eichhorniae in April 1983; and S. albiguttalis in August 1983. Release efforts consisted of the following: N. bruchi and S. albiguttalis at the Old River Site; N. eichhorniae and S. albiguttalis at the White Slough Site; all three species at the Trapper Slough and Veale Tract sites. This release scenario was used to determine the effectiveness of different combinations of the biocontrol agents. Population levels of N. bruchi were successfully established at the Old River and Veale Tract sites. Population levels necessary to effect widespread damage to the waterhyacinth population were observed at the Old River Site. Neochetina eichhorniae was successfully established at the White Slough and Veale Tract sites, but control effectiveness was not demonstrated. The establishment of S. albiguttalis was not confirmed at the four sites. The establishment of new colonies of the biocontrol agents by natural dispersion from the release sites was not demonstrated. It was evident that the widespread effectiveness of chemical control in the Delta reduced the ability of the insects to disperse. Recommendations for more effective use of biocontrol in the San Joaquin River System are presented. These recommendations center on the establishment of biocontrol agent populations in the upstream portions of the San Joaquin River System.
Description: Technical Report
Gov't Doc #: Technical Report A-88-7
Rights: Approved for public release; distribution is unlimited
Appears in Collections:Technical Report

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