Objective:
Preliminary assessment of the host specificity of two potential biological control agents, the galling flies, Ophiomyia alternantherae and Ophiomyia buskii.

Approach:
USDA-ARS-SABCL will assist the CSIRO with a preliminary assessment of the host specificity of two potential biological control agents, the galling flies, Ophiomyia alternantherae and Ophiomyia buskii. A SABCL scientist will collect populations of the two flies and maintain colonies on alligator weed (Alternanthera philoxeroides) at the SABCL. The scientist will also collect and maintain healthy plants for host range testing, including 3 species in the Alternanthera genus and 6 species in the Amaranthaceae family (but not in the Alternanthera genus). These species will be nominated based on availability and relatedness to alligator weed, and then approved by the CSIRO technical contact. Using standard procedures, SABCL will then conduct a series of no-choice tests to determine the host range of the two flies. There will be a minimum of 4 replicate tests for each species and the number of galls and subsequent adult flies produced will be recorded for each test. A final report will be submitted to CSIRO with the dates of tests and a comparison of galls and adults produced on all test plants, including a control using alligator weed.