Current levels of suppression of waterhyacinth in Florida USA by classical biological control agents |
| |
| Institution: | 1. USDA-ARS, Invasive Plant Management Laboratory, Ft. Lauderdale, FL, USA;2. US Fish and Wildlife, ARM Loxahatchee Wildlife Refuge, Delray Beach, FL, USA;3. Dry Tortugas National Park, Key West, FL, USA;4. Nova University, Ft. Lauderdale, FL, USA;1. Landcare Research, Private Bag 92170, Auckland, New Zealand;2. Landcare Research, P.O. Box 69040, Lincoln, New Zealand;3. Landcare Research, Private Bag 11052, Palmerston North, New Zealand;1. School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa;2. DST-NRF Centre of Excellence for Invasion Biology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa;1. Department of Entomology, Louisiana State University, Baton Rouge, USA;2. Instituto Nacional de Investigación Agropecuaria, INIA LA Estanzuela, Uruguay;3. Fundación para el Estudio de Especies Invasivas, Buenos Aires, Argentina;4. Invasive Plant Research Laboratory, United States Department of Agriculture, ARS, Fort Lauderdale, USA;1. Department of Zoology and Entomology, Rhodes University, Grahamstown, South Africa;2. Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, South Africa;1. Department of Earth Sciences, University of the Western Cape, Private Bag X17, Bellville, 7535, South Africa;2. Discipline of Geography, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, P/Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa;1. Agricultural Research Council: Plant Health and Protection, Private Bag X134, Queenswood, Pretoria, South Africa;2. Helmuth Zimmermann and Associates (Central), Pretoria, South Africa;3. SANBI-Directorate on Biological Invasion, Kirstenbosch, Cape Town, South Africa |
| |
| Abstract: | Waterhyacinth, Eichhornia crassipes (Mart.) Solms (Pontederiaceae), has been a global target for classical biological control efforts for decades. In Florida, herbicidal application is the primary control method employed, usually without regard for the activities of the three biological control agents introduced intentionally during the 1970s, namely Neochetina eichhorniae Warner, Neochetina bruchi, Hustache (Coleoptera: Curculionidae), and Niphograpta albiguttalis Warren (Lepidoptera: Crambidae). A series of field experiments from 2008 to 2010 was conducted at four Florida sites using an insecticide-check approach to quantify the current levels of suppression provided by these agents. In the field N. albiguttalis was rarely found while more than 99% of all Neochetina sp. adults were N. eichhorniae. Although it was not possible to disentangle the relative impacts of Neochetina sp. adults from larvae on individual plant variables, the larvae played a major role in reducing plant biomass and the number of inflorescences. Plots exposed to unrestricted herbivory contained 58.2% less biomass and produced 97.3% fewer inflorescences at the end of the experiments. Despite these large reductions, herbivory decreased waterhyacinth coverage by only 16.8% and most of this was attributed to a low-nutrient site where coverage was reduced disproportionately. Overall, coverage trended upwards during the course of the experiments and was always close to 100% when the plots were harvested. Although coverage is a somewhat arbitrary metric, especially for floating plants subject to compression and dispersion, it influences the perception of biological control efficacy which, in turn, directly influences herbicide management decisions in Florida. Despite waterhyacinth populations that now produce less than half as much biomass and up to 98% fewer seeds than before the deployment of biological control agents, the overall approach used to achieve maintenance control of the plant in Florida will probably not change unless new biological control agents, such as Megamelus scutellaris Berg (Hemiptera: Delphacidae), can reduce coverage significantly. |
| |
| Keywords: | Waterhyacinth Biological control Herbicides Integration |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
