Cambomba caroliniana Gray (Cabombaceae)

Authors: SCHOOLER, SHON - CSIRO AUSTRALIA; CABRERA-WALSH, GUILLERMO - USDA/ARS/SABCL; JULIEN, MIC - CSIRO FRANCE

Submitted to: Biological Control of Tropical Weeds using Arthropods
Publication Type: Book / Chapter
Publication Acceptance Date: 5/5/2008
Publication Date: 2/2/2009
Citation: Schooler, S., Cabrera-Walsh, G., Julien, M. 2009. Cambomba caroliniana Gray (Cabombaceae). Biological Control of Tropical Weeds using Arthropods. Chapter 6. pp. 88-107

Interpretive Summary: Cabomba, or water fanwort, is a fast-growing submerged aquatic plant that has the potential to infest permanent water bodies in a range of regions – from tropical to cool temperate – throughout the world. It is considered a serious pest in the United States, Canada, the Netherlands, Japan, India, China and Australia, and is present in Hungary, South Africa, and the United Kingdom. Cabomba grows well in slow-moving water bodies. Cabomba negatively affects the environment, recreational activities, public safety, and water quality.The weed can smother native submerged plants, and reduce germination of desirable native emergent plants. Alteration of the flora by cabomba is thought to have reduced populations of platypus and water rats northern Queensland, Australia.Generally herbicides are largely ineffective and herbicide use is severely regulated in or around public water supplies. Drawdown and mechanical control was unsuccessful. We encountered a drastic modification in the growing conditions of plant populations brought about by an environmental factor, whereas in its homeland the plant is found in periodically disturbed unstable patches, in Australia it appears in dense and temporally stable monospecific stands. So far, only one specific agent has been found, and introduced into quarantine in Austrlia, the aquatic weevil Hydrotimetes natans (Col:Curculionidae:Bagoini). We predict that the result will be a reduction of cabomba abundance, particularly in areas of deep water where disturbance will exacerbate the effects of herbivore damage and in shallow areas where damage to cabomba will increase the relative competitive ability of native plant species.

Technical Abstract: Cabomba, or water fanwort, is a fast-growing submerged aquatic plant that has the potential to infest permanent water bodies in a range of regions – from tropical to cool temperate – throughout the world. It is considered a serious pest in the United States, Canada, the Netherlands, Japan, India, China and Australia, and is present in Hungary, South Africa, and the United Kingdom. Cabomba grows well in slow-moving water bodies, preferring areas of permanent standing water less than 4 m deep. Reproduction is almost entirely vegetative throughout most of the introduced localities and any fragment that includes nodes can grow into a new plant. Cabomba negatively affects the environment, recreational activities, public safety, and water quality. The weed can smother native submerged plants, reduce germination of desirable native emergent plants. Alteration of the flora by cabomba is thought to have reduced populations of platypus and water rats northern Queensland, Australia. Generally herbicides are largely ineffective and herbicide use is severely regulated in or around public water supplies. Drawdown and mechanical control was unsuccessful. We encountered a drastic modificaton in the growing conditions of plant poñulations brought about by an environmental factor, whereas in its homeland the plant is found in periodically disturbed unstable patches, in Australia it appears in dense and temporally stable monspecific stands. Under this scenario, it is expected that an agent that is present year-round and hopst-specific should exhibit density-dependent populations that fluctuate with its host population. So far, only one specific agent has been found, and introduced into quarantine in Australia, the aquatic weevil Hydrotimetes natans (Col.: Curculionidae:Bagoini). We predict that the result will be a reduction of cabomba abundance, particularly in areas of deep water where disturbance will exacerbate the effects of herbivore damage and in shallow areas where damage to cabomba will increase the relative competitive ability of native plant species.