Submitted to: Castanea
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/1996
Publication Date: N/A
Interpretive Summary: Not applicable, not original research.
Technical Abstract: Alligatorweed, Alternanthera philoxeroides (Mart.) Griseb., a South American immigrant is an aquatic weed in the southern United States where it roots in shallow water or on shore. Floating stems grow across the surface of the waterway forming a dense interwoven mat. This mat clogs the waterway and outcompetes native plants along shore. Three species of South American insects were released from 1964 to 1971 for biological control of this aggressive invader. The flea beetle Agasicles hygophia Selman and Vogt strips the leaves from the stems and the moth Vogtia malloi Pastrana bores inside the stems. Heavy damage by either species kills the stems thereby causing the mat to break up and clearing the waterway. The thrips Amynothrips andersoni O'Neill feeds on the young apical leaves. Heavily damaged plants are often stunted. Alligatorweed has bee controlled or the populations reduced throughout much of its range, especially in Florida and along the Gulf Coast. Colder climates, though, from Arkansas to North Carolina along the margin of the range preclude establishment of the insects. In some colder areas, for example the lower Mississippi River Valley, the moths and flea beetles immigrate from the warm coastal areas and provide local control.