4d.Progress report.
This report serves to document research conducted under a Reimbursable Cooperative Agreement between the USDA-ARS-South American Biological Control Laboratory (SABCL) and the Commonwealth Scientific and Industrial Research Organization [CSIRO], Canberra, Australia. Alligator weed, Alternanthera philoxeroides, is an amphibious plant indigenous to South America. Biological control of alligator weed had been intensively studied at SABCL in the 1960s. 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 was conducted at SABCL. However, additional biological control agents are needed for control of the weed in its terrestrial form and in cooler regions of Australia.

Major accomplishments: In its native range in Argentina, alligator weed is represented by triploid (hybrids) and diploid (pure) populations. This was confirmed through pollen viability and genetic studies. Additionally, in order to reintroduce the flea beetle Dysonycha argentinesis into Australia, the distribution, life cycle, and the capability to develop on cultivated leaf beet, Beta vulgaris were studied. Insects collected in Buenos Aires (climatically similar to the infested areas in Australia) were used to study its rearing and life cycle. The development of a rearing technique for other potential agent was attempted.