Location: Invasive Plant Research LaboratoryTitle: Release and evaluation of Cyrtobagous salviniae on common salvinia minima in southern Louisiana Author
Submitted to: Journal of Aquatic Plant Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2012
Publication Date: 1/10/2013
Citation: Tipping, P.W., Martin, M.R., Hulslander, W., Pierce, R.M., Smart, M.D., Center, T.D. 2013. Release and evaluation of Cyrtobagous salviniae on common salvinia minima in southern Louisiana. Journal of Aquatic Plant Management. 51:34-38. 2013. Interpretive Summary: We attempted to transfer an effective and safe insect from common salvinia growing in Florida to common salvinia growing in the Jean Lafitte National Park and Preserve in southern Louisiana, where the plant is a significant wetland weed. The insect was a weevil, Cyrtobagous salviniae, which has helped keep common salvinia in Florida in check. A series of permanent sites were established in the Preserve and a total of 9,670 weevils were released from 2002 through 2005. Unfortunately, despite multiple recoveries of weevils, damage to the plant was relatively light, and we could not confirm that the insect had become established. Hurricane Katrina effectively put an end to the project by destroying all of the plots.
Technical Abstract: Common salvinia (Salvinia minima) is one of the most widespread, non-native invasive species at the Barataria Preserve of Jean Lafitte National Historical Park and Preserve in southern Louisiana and currently infests more than 3,600 ha and 48 km of navigable waterways. A proven biological control agent, the salvinia weevil (Cyrtobagous salviniae Calder and Sands), was field collected on S. minima in Florida, checked for pathogens, and then released in the Preserve from June 2002 through June 2005. Only a few weevils were recovered from heavily shaded sites compared to full sun sites where weevils were recovered frequently and S. minima damage was greater. A field nursery site was established at an undisturbed location in Twin Canals in June 2003 and stocked with 2,421 weevils, released periodically until August 2005. Although weevils, including teneral adults, were recovered at all but one release site, population establishment was not confirmed because of multiple perturbations culminating in Hurricane Katrina which destroyed all the sites near at the end of the project. Weevil damage to plants was minimal and localized in release sites which suggested that if C. salviniae did establish, it was present at very low, difficult to detect levels. Any future efforts to relocate this weevil to Louisiana from Florida should focus on identifying full sun, undisturbed sites to expedite establishment.