Discovery and Evaluation of Biological Control Agents of Medusahead Rye and Other Important Weeds of Western U.S. Rangelands
Great Basin Rangelands Research
2012 Annual Report
1a.Objectives (from AD-416):
Search for candidate biological control agents of exotic, invasive weeds of the western U.S. in the Mediterranean Basin and central Asia and study the candidates’ host-specificity and impact on the target weed.
1b.Approach (from AD-416):
Natural enemies (e.g. herbivores, pathogens) will be collected on target weeds in their native range. Characteristics of the natural enemy infestation, such as relative abundance, phenology, and impact on the target weed will be recorded. Natural enemies will be reared and identified by taxonomic specialists and assessed for their potential as biological control agents through host-specificity testing on non-target plant species. A list of test plant species for medusahead rye biological control candidates has been developed and submitted to TAG (USDA-APHIS Technical Advisory Group). The primary goal of this SCA is to discover and develop candidate biological control agents that are highly host-specific and damaging to medusahead rye.
This report documents research conducted under a Specific Cooperative Agreement between ARS and the BIOTECHNOLOGY & BIOLOGICAL CONTROL AGENCY, Rome, Italy. The agreement was established in support of objective 1 of the in-house project in order to facilitate the goals of this objective related to foreign exploration for weed biological control agents. The ADODR monitored the progress of the cooperator’s research via regular telephone and electronic mail correspondence and also met with the cooperator at a scientific conference. Field surveys were conducted for perennial pepperweed (PPW) and medusahead in Bulgaria, China, Italy, Kazakhstan, and Turkey. Two new PPW field sites were established in Bulgaria and several others in southeastern Kazakhstan. Three candidate biological control agents for PPW: Melanobaris semistriata (Coleoptera: Curculionidae); Lasiosina deviata (Diptera: Chloropidae), and Metaculus lepidifolii (Acari: Eriophyoidea) were selected for intensive evaluation (e.g. host-specificity testing, development of mass-rearing methods and assessment of impact to the target weed). An open-field bioassay on these candidates was carried out in central Turkey but test-insect establishment was compromised by inclement weather. This test will be improved and repeated in the next field season. In the meantime, M. lepidifolii will be studied in the laboratory in Italy and Serbia. Medusahead plants samples have been collected for genetic analysis and long-term field surveys of ground-dwelling arthropods associated with medusahead have been initiated in Bulgaria.