4d.Progress report.
This report serves to document research conducted under a specific cooperative agreement between ARS and the Southwest Idaho & RC & D Council. Additional details of research can be found in the report for the parent CRIS 4012-22000-020-00D, Discovery and Initial Development of Classical Biological Control Agents for Invasive Eurasian Weeds Affecting Agricultural and Natural Areas. Field observations and a laboratory host specificity test were conducted for a small chrysomelid beetle discovered on rush skeletonweed, Chondrilla juncea; it is awaiting identification. The behavior of this beetle was studied on caged plants of Chondrilla juncea, Cichrium intybus, Taraxacum officinalis, and Lactuca viminea. In captivity, adults fed and female oviposited on all tested plants. Field observations revealed that feeding and oviposition occurred only on Chondrilla and Lactuca. A laboratory host specificity test of an unidentified yellow and black plant bug (Miridae) was conducted using Chondrilla juncea, Cichrium intybus, Taraxacum officinalis, and Lactuca viminea. Adults fed mainly on Chondrilla but also on a smaller scale on other plants. There was no oviposition observed and no adult survival after 10 days. Field observations showed no feeding or oviposition although damage to Chondrilla was great. An unidentified sawfly was also collected on skeletonweed; preliminary host range testing showed that although the larvae lived only for a short time, they did not feed on any of the test plants except Chondrilla juncea. Larvae of Schinia cognate (Lepidoptera) were collected from Bulgaria and tested in cages under laboratory conditions on Chondrilla juncea, Cichrium intybus, Taraxacum officinalis, and Lactuca viminea. No feeding occurred on plants other than Chondrilla juncea. From a large root collection (210 roots) in winter 2004, 8 adults of Mordellistena micans (Mordellidae) emerged. The emergence was not synchronized, with large intervals of 7 to 12 days, and thus no tests could be conducted in 2005. These results indicate that least 3 insects are promising candidates for future importation and release against Chondrilla juncea in the U.S.