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Title: A field test of selected insects and pathogens for control of waterhyacinths. Report 1, Preliminary results for the 1975-76 season
Authors: Mobility and Environmental Systems Laboratory (U.S.)
Aquatic Plant Control Research Program (U.S.)
Addor, Eugene E.
Keywords: Aquatic plant control
Biological control
Lake Concordia
Publisher: Environmental Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Description: Technical Report
Abstract: During the growing season of 1975, a field experiment was initiated on Lake Concordia, Louisiana, to test the potential effectiveness of selected organisms as control agents against waterhyacinths, Eichhornia crassipes (Mart.) Solms. Ninety-seven floating frames, each approximately 2 m square, were anchored on the lake in open water and planted with waterhyacinths collected from the hyacinth population that grows naturally near the shore of this lake. Sixty of these frames (plots) were subsequently selected for treatment with various combinations of two insects (Arzama densa Walker and Neochetina eichhorniae Warner) and two fungi (Acremonium zonatum (Sawada) Gams and Cercospora rodmanii Conway) in a random block factorial arrangement with four replications per treatment, and four frames were designated as control (no-treatment) plots. The remaining 33 frames were anchored apart from the test frames to be used as spares if necessary. The control and treated plots were weighed at 2-week intervals throughout the growing season, with the intention that weight changes in the plants would be the primary criterion for judging treatment effects. Flowering stalks were also counted, and the plant heights were measured at each weighing date. In addition, observations were made from time to time on insect and pathogen populations on the plots during the season. This report describes the experiment, presents the collected data, and summarizes the observations. Statistical analyses and interpretation of the data are also presented. Preliminary indications are that significant reductions in the growth rate or total accumulation of waterhyacinth mass in the test plots were not achieved by any of the treatment combinations during the first season's tests, but the potential for some of the treatments to effect the desired control began to emerge during the second year of observations. Appendix A discusses the life systems of the control organisms; Appendix B discusses the flowering activity of the waterhyacinths.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Technical Report

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