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Minutes of the
Giant Salvinia Interagency Planning Meeting
Ramada Inn, Houston, Texas
November 17, 1998
- (USFWS), US Forest Service (USFS), Texas Parks and Wildlife Department (TPWD), Louisiana Department of Wildlife and Fisheries (LDWF), Texas Department of Agriculture (TDA), Sabine River The meeting was attended by representatives of the US Department of Agriculture (USDA), US Geological Survey (USGS), US Army Corps of Engineers (USACE), US Fish and Wildlife Service Authority (SRA, Louisiana and Texas), Florida A&M University (FAMU), Texas A&M University (TAMU), Aquatic Plant Management Society (APMS), and Texas Aquatic Plant Management Society (TAPMS). Rhandy Helton (TPWD) chaired the meeting, and Dr. Michael Smart (USACE and TAPMS) recorded the minutes.
- After brief introductions, Larry Hartmann (TPWD) provided an overview of the history of Salvinia molesta in Texas (including the Louisiana portion of Toledo Bend. A two-page chronology was handed out.
- Dr. Jim Hyde (SRA, Louisiana) provided samples of S. minima and S. molesta for observation purposes.
- There was some discussion of the problem of S. molesta being disseminated by aquatic nurseries and several attendees indicated that they had either heard of this happening or had direct, first-hand experience. Unfortunately the perception is that the agencies that would have jurisdiction over such actions are reluctant to prosecute. It is also difficult to obtain information about the source of infestations as individuals and retailers are reluctant to divulge information that may get them or their suppliers in trouble. There was a consensus that the appropriate state and Federal agencies should be encouraged to conduct inspections and issue warnings to violators. The objective of these "enforcement" efforts would be to stop the spread of harmful exotics and not necessarily to generate fines, unless there were repeat offenders.
- Colette Jacono (USGS) provided an overview of the taxonomy and biology of the genus, Salvinia. Taxonomic differences between S. minima and S. molesta were of particular interest. A flyer on S. molesta and a web page address for more information (http://nas.er.usgs/ferns) were made available. Giant salvinia has the potential to be one of the most damaging nuisance aquatic plants that we might experience in the US. Its potential range extends along the Gulf and Atlantic Coasts of the US from Texas to Virginia and west to California, as far north as the San-Joaquin River Delta. Giant salvinia has successfully overwintered in outdoor ponds in North and South Carolina. Giant salvinia has been observed in at least five watersheds in Texas. Common salvinia is now well established throughout Florida and has been in Louisiana since 1980 and in Texas since 1992. Once considered a native species in Florida, it seems likely that common salvinia is of foreign origin. Interestingly, Cyrtobagous salvinae, an aquatic weevil that is considered to be the most promising biological control for giant salvinia, was accidentally introduced and has established in Florida, living on the common salvinia. This opens the possibility for its use a biological control agent in Texas and Louisiana. Ms. Jacono read a quotation from her communications with Dr. David Mitchell, a world authority on giant salvinia, wherein he urged that we take the "strongest possible measures to prevent the plant spreading from this reservoir to any other".
- Larry Fowler (USDA) indicated that USDA has a program for providing emergency cost-shared funds for "eradicating" infestations of new exotic species that pose a threat to the Nation. George Nash (USDA) indicated that funds are usually available, on a cost-share basis. [editor's note: Contribution by a state agency of people's time and equipment may be recognized, in lieu of monies, in fulfilling the state's obligation in a cost-share program.] State and local agencies must agree to implement an eradication program. These USDA emergency funds would not be available simply to provide "control" of the nuisance plant – if the group was going to recommend a control rather than an eradication program then funding would have to be secured elsewhere. He suggested that the group consider developing a long-term program employing an "Integrated Management Systems" approach to eradication of giant salvinia. An Integrated Management Systems approach would involve the combined use of physical, biological, chemical, mechanical, and cultural approaches to prevent the spread of the plant to new areas and eliminate it from existing sites of infestation. An education program, diligent monitoring, and enforcement of laws banning the possession and transport of the plant would be critical components of the overall effort.
- Dr. Jim Hyde described the results of herbicide applications that had been made on the giant salvinia infestation on the Louisiana side of Toledo Bend. Copper mixed with diquat was effective in killing the plant, but populations seemed to recover quickly. Although it was too soon to evaluate efficacy, fluridone treatment did cause the onset of symptoms (chlorosis) suggesting that it would be effective if concentrations could be maintained for a sufficient period of time. Judy Ludlow (FDEP) suggested that, based on results that they had experienced in Florida with common salvinia, that copper alone might be effective in killing giant salvinia in areas near potable water intakes.
- Dr. Mike Grodowitz (USACE WES) provided an overview on biological control of giant salvinia. Because the weevil, C. salvinae, is already established in Florida, he suggested that we should be able to bring it into Texas and Louisiana with just a permit from the respective state agencies. In Florida, the weevil is well established, feeding on S. minima. Because lengthy host-specificity trials would not be required, biological control efforts could begin almost immediately.
- It was agreed that timely dissemination of information on the threat of giant salvinia in Texas and Louisiana was critical and that an updated flyer be prepared for widest possible distribution.
- A period of general discussion followed. Much of the discussion concerned the approach that the group should recommend -- development of an eradication program or an operational control program. Dr. Mike Grodowitz expressed concern that a biological control approach was not compatible with an eradication program. Successful, long-term biological control requires maintaining host plant populations to sustain the insect biocontrols. Dr. Michael Smart (USACE WES LAERF and TAPMS) pointed out that the presence of common salvinia in Texas and Louisiana provides us with a unique opportunity. Because common salvinia will sustain populations of the weevil even in the absence of its true host, giant salvinia, an eradication program could be compatible with, and in fact would rely heavily on, biological control.
- The group then voted on whether to develop an integrated program designed to eradicate giant salvinia, or a biological control program whose goal would be the maintenance of giant salvinia populations at acceptable levels. All but two individuals voted to develop an integrated eradication program.
- Dr. Earl Chilton (TPWD) suggested that we establish a smaller group to develop an action plan that could be submitted to the various state and federal agencies in order to secure funding and initiate control measures. An action Plan Committee (chaired by Dr. Chilton), Biocontrol Committee (chaired by Dr. Grodowitz), and Information /Education Committee (chaired by Colette Jacono) were formed.
- The meeting was adjourned and the Committees met briefly to assign tasks. A target date of December 4, 1998 was set for development of a draft Action Plan.
- Michael Smart
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