For 2020 and newer grants, please go to https://grants.ipmcenters.org/
Home       Current RFAs       PD User Guide       Projects       Login

Funded Project

Funding Program: Regional IPM Competitive Grants - Northeastern

Project Title: Biological Control of Swallow-Worts in the Northeast - Part 2

Project Director (PD): Richard A. Casagrande [1]

Lead State: RI Lead Organization: University of Rhode Island

Research Funding: $24,290

Start Date: Jun-01-2009 End Date: May-31-2010

Pests Involved: swallow-wort, swallowwort, weeds

Site/Commodity: landscape

Area of Emphasis: biological control, biological control, invasive species

Summary: Two species of European swallowworts, Vincetoxicum nigrum (black) and V. rossicum (pale) have invaded the USA and are spreading throughout the Northeast and beyond. Swallow-worts contain a haemolytic glycoside which is toxic to grazing animals. In addition to pastures, swallow-worts invade gardens, lawns, shrubs, hedgerows, forests, ornamental plant nurseries, Christmas tree farms, and pine plantations. The twining climbing plants smother plants, serve as alternate hosts for Cronartium rusts of pines, and induce monarch butterflies to lay eggs on these plants where larvae cannot survive. Swallow-worts are difficult to control mechanically or chemically and native herbivores have little impact. In response to stakeholder requests, we initiated a biological control program on swallow-worts and in 2006 we collected insect herbivores throughout Europe. We presently have five European insect herbivores of swallow-worts in quarantine where we have made good progress on host range testing and already identified two agents as particularly promising. We seek support to continue host range testing of promising natural enemies and to measure their impact on the target weeds toward the goal of bringing North American swallow-worts under biological control. The objective of this proposal is to evaluate the host range and potential impact of European insect herbivores under consideration for biological control of swallowworts in North America. We anticipate giving several research presentations, submitting five journal articles, and preparing a petition for biological control agent release during the funding period covered in this proposal. This multi-disciplinary, international research project meets NEREAP-IPM goal 3: "...reduce unreasonable adverse environmental effects from pests and pest management practices." As serious weeds in ornamental nurseries and Christmas tree plantations, swallow-worts qualify under NEREAP-IPM priority one for 2006 and priority 3 (minor crop) for 2007. Objectives: The general objective of this project is to evaluate the potential of European insect herbivores to provide biological control of swallow-worts in eastern North America. Our specific objectives for this proposal include: 1) Completing host range testing of agents now in quarantine. 2) Evaluating potential impact of these agents upon swallow-worts. Proposal USDA CRIS data Note this project is a continuation of a 2008 RIPM project - please see Part 1 for the 2009 Progress Report.

Final Report:

Outcomes Changes in Knowledge: We have a TAG test plant list with 86 species on it including 3 target hosts. With H. opulenta we have tested 75 of these species to date in no-choice experiments. In these trials the target plants (Vincetoxicum nigrum, V. rossicum, and V. hirundinaria) are consistently attacked. The 72 non-target species tested to date do not support larval development. We have 11 remaining plant species to test and we are working to procure these species to complete this testing. Similarly, with A. asclepiadis we have found consistent high larval development on the 3 target species but no successful development on 34 non-target species. We will test the remaining plants on the TAG list with both moths, but based upon results obtained to date, both species appear to be completely specific to the genus Vincetoxicum which is represented in North America by only the two target weeds (black and pale swallow-worts.) Results with E. asclepiadeus have been encouraging, but not without some complications. It is apparent that larvae can complete development on the roots of several species in the subtribe Asclepiadinae of the family Asclepiadaceae under no-choice conditions. Further studies involving adult oviposition behavior are underway at CABI-Europe in Switzerland. Impact studies were conducted in Switzerland where the density-dependent effects of leaf herbivory by A. asclepiadis and root herbivory by E. asclepiadeus were evaluated singly on Vincetoxicum performance held under full sun conditions. The negative effects of root herbivory increased with density, but leaf herbivory had no effect on Vincetoxicum performance. At densities greater than 20 larvae per plant, larval damage by E. asclepiadeus reduced entire plant biomass and shoot height. Based upon these results, it appears that E. asclepiadeus could have a substantial impact on the target weeds growing in full-sun. Pre-release Monitoring: We have conducted preliminary assessment of release sites for potential biological control agents from 2008-2010. In Rhode Island there are three sites: an abandoned pasture in Charlestown, an active pasture in Jamestown, and a nature preserve on Block Island. In all three of these Rhode Island sites we have confirmed that only Vincetoxicum nigrum is present. On Naushon Island in Massachusetts there are populations of both V. nigrum and V. rossicum. We plan to conduct both pre- and post-release monitoring at all four of these sites. Each year we have conducted pre-release monitoring at these sites using 2 - 1 square meter quadrats per site; data collected included stem density, seedling density, percent cover by species of Vincetoxicum, and percent cover of other plant species. We found no insect feeding damage in any of the plots. These data will be used for comparison to post-release results if biological control agents are released.

Impacts Over the course of this funded project we gave research presentations on our results in Albany NY, Harrisburg PA, Syracuse NY, Ottawa Canada, San Diego CA, and at the International Congress of Weed Biocontrol in Montpellier, France. The results of this research are presented in six publications including two already published, three in press, and one under revision. Based upon research results on the five agents under consideration, we focused our research on three species; the root feeding beetle, Eumolpus asclepiadeus and the foliage feeding moths, Hypena opulenta and Abrostola asclepiadis. Publications: Weed, A.S., Casagrande, R.A. 2010. Biology and larval feeding impact of Hypena opulenta (Christoph) (Lepidoptera: Noctuidae): a potential biological control agent for Vincetoxicum nigrum and V. rossicum. Biological Control 53: 214-222. Weed, A.S. 2010. Benefits of larval group feeding by Chrysolina a. asclepiadis on Vincetoxicum: improved host location or feeding facilitation? Entomologia Experimentalis et Applicata. In press. Weed, A.S., Casagrande, R.A. 2010. Effects of leaf and root herbivory by potential insect biological control agents on the performance of Vincetoxicum spp. Biological Control: In press. Weed, A.S., Casagrande, R.A., A. Gassmann, and A. Leroux. 2010. Performance of potential European biological control agents of Vincetoxicum spp. with notes on their distribution. Journal of Applied Entomology: In press. Weed, A.S. Casagrande, R.A. 2011. Host range assessment of Hypena opulenta; a potential biological control agent of swallow-worts (Vincetoxicum). Environmental Entomology: In prep. Weed, A.S. 2010. Biology and Ecology of European Natural Enemies of Swallow-Worts (Vincetoxicum) and the Potential for Biological Control. PhD dissertation, Dept. Plant Sciences, University of Rhode Island, 196 pp.

Report Appendices Final Report 2010 [PDF]

Close Window

Northeastern IPM Center 340 Tower Road Cornell University Ithaca, NY 14853 NortheastIPM.org		Developed by the Center for IPM © Copyright CIPM 2004-2026