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United States Department of Agriculture

Agricultural Research Service

2011 Annual Report

1a.Objectives (from AD-416)
Objective 1: Develop and coordinate biological control programs to achieve sustained suppression of Lepidium draba L. (Brassicaceae), Centaurea spp., Hieracium spp. (Asteraceae), Tamarix spp. (Tamaricaceae), Euphorbia esula L. (Euphorbiaceae), and other invasive plants by: 1a) determining the systematics and phylogeography of target species; 1b) identifying, testing and releasing new arthropods and plant pathogens alone and in synergistic combinations; 1c) assessing rates of establishment, population growth, dispersal and impacts of agents on target weeds, native plants, and associated soil microbial communities; and 1d) integrate biological control agents with chemical, cultural and other control methods to enhance the impact of weed management programs. Objective 2: Identify key factors and mechanisms affecting the success of biological control programs and plant invasions including: 2a) genetic and phenotypic traits of target weeds that determine the success of invasive plant species in distinct ecological regions; 2b) genetic and phenotypic traits of biological control agents affecting their establishment, population growth, and impact; 2c) the biotic, edaphic, and environmental factors and mechanisms affecting weed establishment and expansion, and success of biological control agents; and 2d) integrate population information from Objectives 1 and 2 with remote sensing imagery and other spatial/temporal databases to develop spatial models of weed invasion risk.

1b.Approach (from AD-416)
Exotic invasive weeds cause about $27 billion annually in economic losses in addition to environmental impacts ranging from displacement of species of conservation concern to altered ecosystem functions. Biologically-based control methods can provide cost-effective, sustainable means of limiting the adverse impacts of invasive plants over extensive rangeland and natural areas. Our studies will focus on increasing the success of biological control efforts through better scientific understanding of: mechanisms underlying both the impact of agents and patterns of weed and agent dispersal; genetic variation within target weeds and biological control agents; evolutionary relationships of target weeds and agents; synergisms between plant pathogens, deleterious microbes, and arthropod agents; direct and indirect effects of biological control introductions on nontarget organisms in a risk analysis context; environmental factors affecting weed and biological control agent dynamics and invasion risk; and follow-on effects following suppression of weeds by biological control agents. Anticipated products of our project include new biological control agents, improved systematic and phylogeographic understanding of target weeds and control agents, improved systems for assessing and monitoring weed and insect populations; elucidation of factors and mechanisms limiting the establishment and success of biological control releases.

3.Progress Report
This is the final report for the bridging project #5436-22000-015-00D that was terminated on January 31, 2011 and replaced with project #5436-22000-017-00D “Reducing the Impact of Invasive Weeds in Northern Great Plains Rangelands through Biological Control and Community Restoration”, which started on February 1, 2011. Accomplishments and International Collaborations are listed in the #5436-22000-017-00D report. Hawkweed Invasion: We discovered and collected a potential classical weed biocontrol fungus on hawkweed populations in France, an occurrence not previously reported. This fungus is now in quarantine testing in MT in hopes that it will be effective against the hawkweed invasion of the Northern Rockies. Restoration After Invasion: Plant invasions can alter the soil microbial community, making it hard to establish desired plants after the plant invasion is controlled. We established new methods for identifying microbial species that are predominant in soils around invasive weed roots. This knowledge will help us develop strategies for restoration of desirable plant communities, including which restoration species can tolerate the legacy of soil bacteria, and which species can return the soil to pre-invasion conditions.

Review Publications
Piesik, D., Panka, D., Delaney, K.J., Skoczek, A., Lamparski, R., Weaver, D.K. 2011. Cereal crop volatile organic compound induction after mechanical injury, beetle herbivory (Oulema spp.), or fungal infection (Fusarium spp.). Journal of Plant Physiology. 168(9): 878-886.

Caesar, A.J., Caesar, T., Lartey, R.T. 2010. First report of anthracnose stem Canker of the invasive perennial weed Lepidium draba caused by Colletotrichum higginsianum in Europe. Plant Disease. 94:1166-1166.

Espeland, E.K., O'Farrell, M.R. 2010. Small Variance in Growth Rate in Annual Plants has Large Effects on Genetic Drift. American Journal of Botany. 97(8): 1407–1411.

Espeland, E.K., Emam, T. 2011. The value of structuring rarity: the seven types and links to reproductive ecology. Biodiversity and Conservation Journal. 20(5): 963-985.

Gaskin, J.F., 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.

Wheeler, G.S., Taylor, G.S., Gaskin, J.F., Purcell, M. 2011. Ecology and management of Australian pine (Casuarina spp.), an invader of coastal Florida, USA. Journal of Coastal Research. 27(3):485-492.

Szucs, M., Swarzlaender, M., Gaskin, J.F. 2011. Reevaluating establishment and potential hybridization of different biotypes of the biological control agent Longitarsus jacobaeae using molecular tools. Biological Control. 58:44-52.

Dalin, P., Bean, D.W., Dudley, T., Carney, V.A., Eberts, D., Gardner, K.T., Jones, E.M., Kazmer, D.J., Michels Jr, G.J., O'Meara, S.A. 2010. Seasonal adaptations to day length in ecotypes of Diorhabda spp. (Coleoptera: Chrysomelidae) inform selection of agents against saltcedars (Tamarix spp.). Ecological Entomology. 39(5): 1666-1675.

Shi, X., Wang, J., Dao-Yuan, Z., Gaskin, J.F., Pan, B. 2010. Pollen source and resource limitation to fruit production in the rare species Eremosparton songoricum (Fabaceae). Nordic Journal of Botany. 28: 438-444.

Shi, X., Wang, J., Zhang, D., Gaskin, J.F., Pan, B. 2010. Pollination ecology of the rare desert species Eremosparton songoricum (Fabaceae. Australian Journal of Botany. 58(1): 35–41.

Goergen, E., Leger, E., Espeland, E.K. 2011. Native perennial grasses show evolutionary response to Bromus tectorum (Cheatgrass) invasion. PLoS One. 6(3): e18145 (1-8). doi:10.1371/journal.pone.0018145.

Caesar, A.J., Caesar, T., Sainju, U.M. 2010. The plant pathology of native plant restoration. Environmental Research. 4(3/4): 403-414.

Piesik, D., Lemnczyk, G., Skoczek, A., Lamparski, R., Bocianowksi, J., Kotwica, K., Delaney, K.J. 2011. Fusarium infection in maize: Volatile induction of infected and neighboring uninfected plants has the potential to attract a pest cereal leaf beetle, Oulema melanopus. Journal of Plant Physiology. 168:1534-1542.

Last Modified: 11/29/2015
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