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United States Department of Agriculture

Agricultural Research Service

Research Project: Biological Control of Invasive Weeds
2012 Annual Report


1a.Objectives (from AD-416):
To facilitate and perform discovery and development of biological control agents against invasive weeds.


1b.Approach (from AD-416):
Core funding supports detailed work on five weeds currently identified as primarily important. If additional weed species are targeted then the budget will be adjusted accordingly. The basic pattern of the work is to.
1)perform literature and personal review of existing information in order to optimize chances of finding weeds in their native ranges where biological control agents are most likely to be encountered,.
2)find populations of the weed species in its native range,.
3)perform surveys for herbivorous insects, mites, and pathogens associated with the weed species,.
4)test efficacy and specificity of possible biological control agents in field trials in the native range as well as in facilities in Italy,.
5)ship potential biological control agents under appropriate permits to quarantine facilities of cooperating stakeholders,.
6)report results annually and comprehensively in English in a format that can be widely distributed by ARS, and.
7)publish results in peer reviewed journals as appropriate. This work will be performed in cooperation with EBCL staff as appropriate and involve other collaborators as determined necessary by BBCA.


3.Progress Report:

3. Progress Report: Cooperative exploration and host range evaluation research was conducted by the Biotechnology and Biological Control Agency (Rome) on several EBCL target weeds. During the reporting period, BBCA worked on natural enemies of five target weeds: yellow starthistle (YST), perennial pepperweed (PPW), Russian thistle, Scotch thistle, and giant reed (Arundo). Under the parent ARS project subobjective 1A for genetic studies of candidate biocontrol agents, we completed the genetic analysis of immature and adult stages of the weevil, Ceratapion basicorne, reared from the test plant material (two biotypes of YST and two varieties of safflower) from last year’s open field test in Rome. We collected Metaculus lepidifolii on PPW and shipped the material (living specimens, and those killed in ETOH for genetic analysis) to the University of Belgrade in Serbia. Under subobjective 1B to explore for and obtain new candidate agents, we collected arthropods associated with giant reed in Sicily for a cooperative project with EBCL and ARS in Texas. Under subobjective 2A to evaluate candidate agents, an open field test for the YST project was performed at Igdir, Turkey, to evaluate the host range of the seed feeding weevil, Larinus filiformis. The field plot was established in cooperation with Turkish colleagues using plants grown from seed sown in autumn 2011 and spring 2012. Plants were harvested in August and insects emerging from the capitula and stems were kept for morphological and genetic analysis. For the Scotch thistle project, an open field test was carried out at Agricultural University of Plovdiv, Bulgaria, and at the YST field plot in Turkey, to evaluate the host range of the seed feeding weevil, Larinus latus, and the stem boring weevil, Lixus cardui. A Latin square design (10x10) was performed in Bulgaria, while the field plot in Turkey was the same as described above for the open field test for Larinus filiformis on YST. For the Russian thistle project, two field-cage host range tests (multiple choice) were performed at BBCA, with three stem boring insects, two weevils, Cosmobaris sp. nr. scolopacea and Lixus rosenschoeldi, and one moth, Gymnancyla canella; collected respectively in Sicily (weevils) and in central Turkey (moth). The experiment is still in progress and will be harvested in autumn 2012. A no-choice bioassay was carried out in a wind-tunnel to evaluate the physiological and behavioral responses of a Greek population of the mite Aceria salsolae on different test plants vs. Russian thistle. For the PPW project, an open field host specificity test was carried out in central Turkey in cooperation with CABI Bioscience for a root boring weevil, Melanobaris semistriata, and an eriophyid mite, Mecalus lepidifolii, on 10 plant species replicated 12 times. The experiment started in early April from seeds sown in the previous fall, and it was harvested in early August. Data collection is still underway at CABI labs (assessing weevil damage to roots), and BBCA (extraction of mites from leaves). In cooperation with CABI-Bioscience, several related side projects were also conducted that relate to ARS projects at other locations. For the Russian olive project, open field tests were conducted in northeastern Iran to evaluate the host range of the eriophyid mite Aceria angustifolia, and in central Turkey to evaluate the impact of this mite on the target. For the Russian knapweed project, an open field test was carried out in northeastern Iran to evaluate the host range of the mite Aceria acroptiloni. Additional bioassays in the laboratory were done at Belgrade University, Serbia. Additional details about the parent project can be found in the report for 0212-22000-25-00D - Discovery and Evaluation of Classical Biological Control Agents for Invasive Eurasian Weeds Affecting Agricultural and Natural Areas. To discuss project progress, the ADODR corresponded during the year by electronic mail and telephone and via personal meetings with the BBCA cooperators at EBCL and other scientific meetings.

The most significant accomplishment during 2012 was research that provided additional justification for the release of a biocontrol agent of yellow star thistle. Yellow star thistle is one of the most important weeds of rangelands in the western U.S., where it encroaches on native vegetation, especially grasses, and renders millions of acres unusable by livestock. ARS researchers have demonstrated that the root boring weevil, Ceratapion basicorne, is an effective biocontrol agent for this noxious weed, and submitted a petition for release in 2005. This petition was approved by the Technical Advisory Group; however, APHIS did not approve the release because the insect occasionally laid eggs and fed on safflower in no-choice laboratory bioassays. Subsequently, ARS (Albany, CA) and BBCA researchers performed an open field test where we exposed weevils to a matrix of yellow star thistle and safflower plants (including linoleic and oleic cultivars) in a 1:25 ratio, respectively. Results demonstrated that adult Ceratapion basicorne was only found on yellow star thistle; conversely, other Ceratapion species were present on safflower. A paper reporting these findings has been submitted to the scientific journal Biological Control, and will hopefully lead to approval of the petition, and release of the weevil for suppression of yellow star thistle in the U.S.

Our cooperative research involved a variety of international collaborations: Bulgaria – BBCA has a research agreement with colleagues of the University of Plovdiv, who assist in exploration for agents and with field research on weed targets (YST, Scotch thistle and medusahead) that occur in the Balkans. Italy – BBCA has an official agreement with ENEA, the Italian National Agency for Energy, New Technologies and Environment, which hosts our laboratories and facilities. BBCA also has several years of cooperation with several universities in Italy (Rome, Aquila, Bari) on taxonomic and genetic identification of plant and arthropod samples collected during our explorations in Eurasia and/or on material extracted from the open field host range tests. Russia – BBCA has cooperated for several years with the Zoological Institute of the Russian Academy of Sciences, St. Petersburg, who assist in exploration for agents and with field research on weed targets and on taxonomic support. Serbia – BBCA has a research agreement with colleagues at the University of Belgrade, who assist in exploration for agents and with field research on weed targets (Scotch thistle, Russian thistle and medusahead) that occur in the Balkans.

Switzerland – BBCA has a 5-year agreement with the CABI- Bioscience Institute in Délémont. The agreement, based on three weed projects (PPW, Russian olive and Russian knapweed) is focused in supporting foreign explorations for, and evaluation of, numerous biocontrol agents of the target weeds. Turkey – BBCA has almost 10 year of cooperation with the University of Erzurum. In addition, new contacts are under development with Dr. Evrim Koracetin of the University of Kayseri, and with Prof. Rustem Hayat of the University of Isparta, with the aim to set up Research Agreements with both Universities for field activities during 2013.

During 2012 our research resulted in the following publications:

Publications in ARIS with an EBCL coauthor: 1. #262373. Gaskin, J. Bon, M-C, Cock, M.J.W., Cristofaro, M., De Biase, A., De Clerck-Floate, R., Ellison, C.A., Hinz, H., Hufbauer, R., Julien, M., and Sforza, R. 2011. Applying molecular-based approaches to classical biological control of weeds. Biological Control 58, 1-21. Publications with other ARS coauthors: 2. A. Stoeva, V. Harizanova, E. de Lillo, M. Cristofaro, L. Smith. 2012. Laboratory and field experimental evaluation of host plant specificity of Aceria solstitialis, a prospective biological control agent of yellow starthistle.. Exp. Appl. Acarol. 56(1): 43-55 3. Cristofaro M., De Biase A. and Smith L. 2012. Field release of a prospective biological control agent of weeds, Ceratapion basicorne, to evaluate potential risk to a nontarget crop. Biological Control (in press)


Last Modified: 7/28/2014
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