Species Management and Control Information

European water-chestnut
Trapa natans L.

Source: The following information is taken from a number of sources and those sources are identified at the beginning of the referenced information. The intent of this resource is to provide the user with as much of the information that exists for management and control of this species as is practical. It is important to note that new and improved methods are added regularly which will require you to visit the websites provided for updates on this information. Bibliographies and resources referenced by these sources are not included here, but are included at the websites from which this information was extracted.

READ THIS FIRST! Before administering any of the following management and control options, it is imperative that you are familiar with the background information provided under the General Management and Control Section. For additional, and potentially more current, information on management and control of this species, use the Mid-Atlantic Exotic Pest Plant Council (MA-EPPC) listserve or any of the other listserves identified in the Resource - Listserve section of this tutorial. You will find directions for subscribing to the list serve there. The MA-EPPC listserve has an archives feature that saves past discussions (beginning in 1999) about specific species control. These messages are at: http://groups.yahoo.com/group/ma-eppc/messages.

MANUAL AND MECHANICAL CONTROL:

Delaware River Invasive Plant Partnership - Invasive Plant Fact Sheets - http://www.paflora.org/DRIPP.html - Authors: Ann F. Rhoads and Timothy A. Block - April 2002

Control of this species has consisted primarily of mechanical harvesting of the floating mats by means of weed harvesters used to clear waterways. Repetitive harvesting over a number of years may be effective in eradicating this aquatic weed in small enclosed bodies of water. However, such mechanical harvesting likely will only serve to open navigation passageways in waterways on an interim basis and will not provide a long-term solution in heavily infested areas of large lakes or streams.

BIOCONTROL:

Delaware River Invasive Plant Partnership - Invasive Plant Fact Sheets - http://www.paflora.org/DRIPP.html - Authors: Ann F. Rhoads and Timothy A. Block - April 2002

Attempts have been made to find suitable biocontrol insects through searches conducted in 1992 and 1993 in China, Japan, South Korea, and the Russian Far East but no appropriate candidates were found. A similar attempt was made in 1995 in Europe, including France, Germany, Italy, and Poland without success. Potential natural enemies have been reported from warmer climates such as in India. Such species may not be suitable for the cooler regions of the northeastern United States but may become suitable subjects for study as biocontrol agents if European water-chestnut extends its range further southward into warmer areas of the United States.

USDA Forest Service - Biological Control of Invasive Plants in the Eastern United States, http://www.invasive.org/eastern/biocontrol/3WaterChestnut.html - Publication FHTET-2002-04 - Authors: R. Van Driesche, et al. - 2002

Although T. natans continues to be a problem that requires expensive control efforts, no biological control research is being conducted at this time, but future research could help develop biological controls for the weed.