4.What were the most significant accomplishments this past year?
This report serves to document research performed under a reimbursable Cooperative Agreement (No. 58-4005-2-F075) between USDA-ARS-OIRP and the Commonwealth Scientific and Industrial Research Organization [CSIRO], Canberra, Australia, started in March 2002. Biological control of alligator weed had been intensively studied at SABCL in the 60´s, including most of the original research on the flea beetle Agasicles hygrophila, the moth Arcola malloi and the thrips Amynothrips andersoni, that have been introduced into the U.S. and many other countries. Additional biological control agents are needed for the control of the terrestrial form and in cooler regions of Australia.

Major accomplishments: Alligator weed was confirmed to have both sexual and asexual reproduction. The production of seeds is only in specific places. Preliminary genetic studies revealed the presence of hybrids and high infertility of the seeds. Several species of natural enemies appear to have potential for biocontrol because of their apparent specificity, damage, and occurrence: Systena spp., three species of Agromyzidae, Clinodiplosis alternantherae, Agasicles spp. and Disarycha argentinesis. As the investigations progress, it is anticipated that two species of Agromyzidae, Systena and Clinodiplosis alternantherae would be ready for release in Australia in 2005-2006. New enemies were reported for the first time: the flea beetles Systena nitentula, S. silvestrii, Phenrica poss. litoralis, and other polyphagous species such as S. poss. bonariensis, S. poss tenuis and the moth Herpetogramma bipunctalis. Studies on host specificity of S. nitentula revealed a wide laboratory host range, damaging Beta vulgaris (leaf beet), and will be discarded as control agent.