PS 30-146 - The cost and effectiveness of small-scale control methods on fennel, Foeniculum vulgare, in Natividad Creek Park, Salinas, CA

Tuesday, August 7, 2007
Exhibit Halls 1 and 2, San Jose McEnery Convention Center
Abigail E. Gwinn, CSU, Monterey Bay and Return of the Natives Restoration Education Project at the Watershed Institute, Soledad, CA
Invasive species in the United States cost federal and state governments billions of dollars per year and are spreading through wildlife habitat at a rate of about 700,000 acres per year. Information on effective methods of controlling invasive species is crucial to land managers and others who seek to remove invasive species and restore their lands to a more natural state. This study examines three control methods for fennel (Foeniculum vulgare) in a small-scale infestation in two sites in Salinas to determine which is most effective while costing the least. The methods are: digging out individual plants, chopping the plants repeatedly during the summer with a machete, and chopping the plants and immediately spraying the stumps with an application of the herbicide Rodeo. I discovered that the most effective method was digging each plant individually, with chopping and spraying with herbicide a close second. The method of chopping repeatedly was not effective at all with a mortality rate very similar to my control group of plants which received no treatment. I also found that the least expensive method was chopping and spraying with chopping repeatedly a close second. Digging the individual plants was the most time consuming and therefore the most expensive. My recommendation for controlling fennel based upon my results is that chopping and spraying each plant with an herbicide is the most effective and least expensive treatment method. However, if soils are soft and the infestation is small, digging up each individual plant is the best treatment method.
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