USING REMOTE SENSING TO ASSESS BIOLOGICAL CONTROL OF GIANT SALVINIA

Authors: Everitt, James; FLORES, D. - USDA-APHIS; DAVIS, MICHAEL RENE - 6204-05-00

Submitted to: Journal of Aquatic Plant Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/2005
Publication Date: 8/16/2005
Citation: Everitt, J.H., Flores, D., Davis, M. 2005. Using remote sensing to assess biological control of giant salvinia. Journal of Aquatic Plant Management. 43:76-80.

Interpretive Summary: Giant salvinia is an exotic, invasive, aquatic fern that often invades and clogs waterways in subtropical and tropical areas of the world. The salvinia weevil has been used extensively for controlling giant salvinia. Remote sensing techniques were evaluated for assessing control of giant salvinia by the salvinia weevil in southeast Texas. Ground reflectance measurements showed that giant salvinia plants exhibiting moderate and severe feeding damage by the salvinia weevil had lower visible and near-infrared reflectance measurements than healthy plants. Healthy, moderately damaged, and severely damaged giant salvinia plants could be distinguished in an aerial color-infrared photograph. These results should be of interest to wetland resource managers.

Technical Abstract: A study was conducted on a small pond in southeast Texas to evaluate the potential of using remote sensing technology for assessing feeding damage on giant salvinia (Salvinia molesta Mitchell) by the salvinia weevil (Cyrtobagous salviniae Calder and Sands). Field spectral measurements showed that moderately damaged and severely damaged plants had lower visible and near-infrared reflectance values than healthy plants. Healthy, moderately damaged, and severely damaged giant salvinia plants could be differentiated in an aerial color-infrared photograph of the study site. Computer analysis of the photograph showed that the three damage level classes could be quantified.