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United States Department of Agriculture

Agricultural Research Service

Research Project: SOUTH AMERICAN BIOLOGICAL CONTROL AGENTS TO SUPPRESS INVASIVE PESTS IN THE U.S. Title: Alternathera philoxeroides (Martius) Grisebach - alligator weed

Authors
item Julien, Mic -
item Sosa, Alejandro -
item Chan, Richard -
item Schooler, Shon -
item Traversa, Guadalupe -

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: November 30, 2010
Publication Date: March 1, 2012
Citation: Julien, M., Sosa, A., Chan, R., Schooler, S., Traversa, G. 2012. Alternathera philoxeroides (Martius) Grisebach - alligator weed. Book Chapter. In: Julien, M.; McFadyen, R.; Cullen, J., editors. Biological Control of Weeds in Australia.Australia: CSIRO Publishing. p.43-51.

Interpretive Summary: Biological control program of the amphibian invasive plant, alligator weed, began when George Vogt (USDA) conducted several surveys by public transport in South America during the 1960s. From his work, three biological agents were proposed and released in USA, and two of them in Australia. The first one, a flea beetle, provided control of the weed in aquatic habitats in warm temperate areas. Unfortunatley, alligator weed also grew in semi aquatic and terrestrial situations and control agents were needed for those habitats. Therefore, new surveys were conducted in South America from 2001 to 2005. We found and selected four insects for further studies, but they were not suitable, two others, a flea beetle and a node gall fly, are currently in quarantine, while several others, a stem mining fly and two leaf-mining flies should be studied in the future. We also collected a rust in Bolivia but not further South (Argentina). This plant pathogen may also have potential to control alligator weed but first we must determine if it can infest Australian forms of alligator weed as it does not occur on alligator weed in Argentina.

Technical Abstract: Biological control of Alternanthera philoxeroides, alligator weed, began when George Vogt, USDA, conducted several surveys by public transport in South America during the 1960s. Three agents were released in USA and two of them, the flea beetle Agasicles hygrophila and the moth Arcola malloi were released in Australia in the 1970s. The flea beetle provided control of alligator weed in aquatic habitats in warm temperate areas. However, alligator weed also grew in semi aquatic and terrestrial situations and control agents were needed for those habitats. New surveys were conducted in South America from 2001 to 2005. As a consequence four insects were studied, but they were not suitable, two others, the flea beetle Phenrica sp. and the fly Ophiomyia marelli, are currently in quarantine, while several others, the stem mining fly Ophiomyia buski and leaf mining flies Ophiomyia alternantherae and Pegomya sp., should be studied in the future. A fungus Uredo pacensis known to infest alligator weed in Bolivia may also have potential but first it must be determined if it can infest Australian forms of alligator weed as it does not occur on alligator weed in Argentina.

Last Modified: 7/25/2014
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