Progress 10/01/03 to 09/30/07
Outputs
OUTPUTS: Lily leaf beetle parasitoids are now established and spreading in four New England states as a result of our biological control program. Populations of the birch leafminer have declined to a point that we have not seen any damage from this pest in Rhode Island since 2003. Pest populations were virtually undetectable throughout the northeast in 2007. Cypress spurge is under good biological control in pastures distributed throughout RI and biological control agents will spread throughout the state. Purple loosestrife populations are permanently suppressed at Roger Williams Park Zoo and at several other sites in RI and natural enemies are spreading throughout the state. We have identified 6 European insects with potential for biological control of swallow-worts and we are now evaluating them in our quarantine laboratory. Collaborating scientists at Cornell and in Europe have identified 3 promising biological control agents which may provide control of exotic Phragmites
australis with little or no direct effect upon native phragmites. We are presently evaluating host specificity of these species in our quarantine laboratory.
PARTICIPANTS: R.A. Casagrande, URI Plant Sciences Lisa Tewksbury, URI Plant Sciences Heather Faubert, URI Plant Sciences
TARGET AUDIENCES: Growers, landscape mangers, homeowners, environmental organizations
PROJECT MODIFICATIONS: There were no major changes from original project description.
Impacts
We have measured local declines in lily leaf beetle pest populations as a result of our biological control efforts. This has resulted in reduced pesticide use and enhanced survival of native lilies. The successful biological control of birch leafminer has resulted in substantial reduction (eventual elimination) of birch leafminer pesticide applications throughout the northeast and increased aesthetic value and survival of previously-infested trees. As a result of our successful biological program against cypress spurge, growers have reduced herbicide applications and increased grazing on previously infested pastures. Successful biological control of purple loosestrife has resulted in increases in diversity and abundance of native plants and animals in wetlands that were previously dominated by purple loosestrife. Native populations of P. australis that we discovered on Block Island and Naushon Island are being preserved. Successful biological control of exotic
phragmites would have beneficial environmental and economic impacts throughout North America.
Publications
- Casagrande, R. A. and J. Dacey. 2007. Monarch butterfly oviposition on swallow-wort (Vincetoxicum spp.). Environ. Entomol. 36(3): 631-636.
- Lambert, A.M., R. A. Casagrande. 2007. Susceptibility of native and non-native common reed to the non-native mealy plum aphid (Homoptera: Aphidae) in North America. Environ. Entomol. 36(2): 451-457.
- Lambert, A.M. and R.A. Casagrande. 2007. Characteristics of a successful estuarine invader: evidence of self-compatability in native and non-native lineages of Phragmites australis. Marine Ecol. Progress Series. 337: 299-301.
- Lambert, A.M., K. Winiarski, and R.A. Casagrande. 2007. Distribution and Impact of Lipara Species on Native and Exotic Phragmites australis. Aquatic Botany. 86: 163-170.
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Progress 01/01/06 to 12/31/06
Outputs
Lily Leaf Beetle. By the 2006 season Tetrastichus setifer was established in RI, MA, NH, and ME. Pest populations are reduced to non-pest status near release sites in MA and RI and parasitoids were found to have moved over five miles from release sites. Lemophagus errabundus is also permanently established in MA where it has spread over one mile from release. High within-season parasitism in 2006 indicates probable establishment of these species and Diaparsis jucunda at several additional sites. Birch Leafminer. In 1994 we released Lathrolestes nigricollis, a European parasitoid against the invasive birch leafminer, Fenusa pusilla in Rhode Island in conjunction with releases by colleagues in MA, NJ, and PA. Since that time, we have followed the expansion of this parasitoid's distribution throughout southern New England and the increase in parasitism rate and declining densities of birch leafminer and the damage that it causes. Samples taken in 2006 showed pest levels
to be virtually undetectable in RI. Cypress Spurge. We initiated this program in 1995 at the request of a grower by working with the leafy spurge program underway in western states. Apthona flava was readily established in several pastures at that farm where it quickly reduced populations of Cypress spurge. We have subsequently released this species at 10 other sites in RI. To date, we are finding excellent cypress spurge suppression in 6 out of the 10 sites, and fair suppression in 2 other sites. Unfortunately, as this pest comes under biological control, some of these same pastures are now experiencing invasion by black swallow-wort Purple Loosestrife. This project was initiated in 1994 at the request of Roger Williams Park Zoo. We released the leaf feeding beetles Galerucella spp. at that site. Within two seasons, feeding damage was evident and by 1998 all purple loosestrife at the site was defoliated. Beetles have remained established at the site ever since, causing a reduction in
loosestrife plant size and abundance with concomitant increases in abundance and diversity of native plant species. Beetles have been distributed to several other sites in RI with similar results. Swallow-wort. While monitoring the successful control of Cypress spurge at Watson farm, Jamestown RI, we discovered black swallow-wort moving into the pastures. Subsequent surveys in 2006 revealed populations of this toxic plant in 20 of 53 pastures surveyed throughout the state including 7 of 10 horse pastures. URI Ph.D. candidate Aaron Weed spent a very successful field season in Europe in 2006. Aaron identified several insect species that feed upon the various swallow-wort species and established colonies of the five most promising species. After conducting basic studies on biology and host range, he returned these species to the URI Insect Quarantine Laboratory for further study. We are presently holding the chrysomelids; Eumolpus asclepiadeus and Chrysolina aurichalcea, the noctuids;
Abrostola asclepiadis and Hypena opulenta and the tephritid Euphranta connexa in our quarantine laboratory where we are conducting studies on biology and host range.
Impacts
We reduced herbicide applications, increased grazing on pastures previously infested with Cypress spurge and began a program in swallow-wort biological control at grower request. The use of biological control increases diversity and abundance of native plants and animals in wetlands that were previously dominated by purple loosestrife. Substantial reduction (eventual elimination) of birch leafminer pesticide applications was achieved throughout the northeast, as well as increased aesthetics and survival of previously-infested trees.
Publications
- Lambert, A,M. and R.A. Casagrande. 2006. Distribution of Native and Exotic Phragmites australis in Rhode Island. Northeastern Naturalist. 13(4):551-560.
- Lambert, A,M. and R.A. Casagrande. 2006. No Evidence of Fungal Endophytes in Native and Exotic Phragmites australis. Northeastern Naturalist. 13(4):561-568.
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Progress 01/01/05 to 12/31/05
Outputs
In our efforts to establish and evaluate European parasitoids against the lily leaf beetle (LLB) in New England, we found in 2005 that the parasitoid Tetrastichus setifer is now established in RI, MA, ME, and NH. LLB populations have declined substantially at the two oldest release sites. We last released T. setifer in Wellesley, MA in 2001 where it has heavily parasitized LLB larvae; 100% parasitism at peak larval density in 2005. We found similar results in Cumberland, RI where we last released T. setifer in 2002, with 100% parasitism at peak larval density in 2005. From the parasitoids released in surrounding states, we found T. setifer establised in Bridgton, ME in 2004, and this season we recovered overwintered parasitoids from Hudson, NH. We also found a consistently high parasitism rate at Cotuit, MA following T. setifer release this season, so we expect the parasioid will successfully overwinter. This parasitoid is now established in the 4 New England States
where we have made releases. T. setifer has also spread several miles from release sites. Working through local garden clubs and the local press, we located 25 lily gardens near our release site in Cumberland, RI. We found T. setifer in 6 of those sites with the most distant recovery over 5 miles from the release plot and 4 of the 6 located at least 0.5 miles distant. Lemophagus errabundus was found in a lily garden 0.75 miles from our Plainville, MA release site in 2005, indicating that it is not only established from releases in 2003 and 2004, but it has spread a considerable distance. We also released this species in our Kingston, RI plot where we found good parasitism in the weeks following release. Diaparsis jucunda has proven to be more difficult to establish against the LLB. It is found at higher elevations in Europe, and appears well-suited for northern New England, but we have not yet recovered overwintered parasitoids at any of our 2004 and 2005 release sites in RI, MA, NH,
or ME. In 2005 we also released LLB larvae parasitized by D. jucunda into our lily plots to determine if this is a better way to establish this species. We have tracked density and parasitism rates of birch leafminer since releasing the European parasitoid Lathrolestes nigricollis against this pest in 1994. This year continued the trend of reduced pest densities and increased parasitism rates that we have observed over the past decade. As in 2004, we observed and had reports of no economic damage from this pest in Rhode Island this season. In comparing native and exotic populations of Phragmites australis, we find the native subspecies to be more susceptible to several introduced herbivores including the aphid Hyalopterus pruni, and the flies Lipara similis and L. rufitarsis. Cypress spurge and purple loosestrife populations continue to decline as we redistribute their European natural enemies statewide. We reared additional Galerucella beetles for release against purple loosestrife
throughout Rhode Island with the cooperation of the RI Dept. of Transportation, and the Wood/Pawcatuck Association in 2005.
Impacts
We have established the lily leaf beetle parasitoid Tetrastichus setifer in 4 New England states where it seems capable of spreading and locally reducing pest populations. We have also established the lily leaf beetle parasitoid Lemophagus errabundus in RI where it has spread at least 0.75 miles. Purple loosestrife and cypress spurge populations continue to decline state-wide and birch leafminers have been reduced to non-pest status as a result of our biological control releases.
Publications
- Tewksbury, L., M. Gold, R. Casagrande, and M. Kenis. 2005. Establishment in North America of Tetrastichus setifer Thomson (Hymenoptera: Eulophidae), a parasitoid of Lilioceris lilii (Coleoptera: Chrysomelidae). Pgs. 142-143. IN: Hoddle, M. Second International Symposium on Biological Control of Arthropods. USDA Forest Service Publ. FHTET-205-08.
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Progress 01/01/04 to 12/31/04
Outputs
After evaluating biology and host specificity of the European parasitoids Tetrastichus setifer, Lemophagus errabundus and Diaparsis jucunda we obtained USDA approval for field releases in Massachusetts and Rhode Island. In 2003 we released all three parasitoid species in RI, MA, NH, and ME, selecting release sites by matching the European climate where each parasitoid predominates. High parasitism among L. lilii larvae indicates that many of these releases were successful. In 2004 we found that Lily leaf beetle populations have declined over 80% as a result of Tetrastichus setifer activity at our initial release site in MA and we see evidence of similar pest population decline (66%) at a release site in RI only two years after parasitoid release. We monitored cypress spurge and the biological control agent, Aphthona flava, in 10 previous release sites. We are finding excellent cypress spurge suppression in 6 out of the 10 sites, and fair suppression in 2 other sites.
Two other sites have yet to experience significant suppression. There were four initial release sites of Galerucella spp. in the Rhode Island biological control of purple loosestrife program. In 2004 two of these sites show significant impact of the Galerucella release. At one site, in Providence RI, there is a noticeable increase in native plant species in the wetland where Galerucella adults were released. The purple loosestrife plant population has also diminished, and the plants that remain are stunted, and produce fewer flowers. We have located native Phragmites australis populations on Block Island in Rhode Island and we are continuing research on natural enemies of both native and exotic populations of P. australis, both here and in Europe toward an ultimate goal of biotype-specific biological control of exotic P. australis. In 1994 we released Lathrolestes nigricollis (Thompson) (Hymenoptera: Ichneumonidae), a European parasitoid of the against the invasive birch leafminer,
Fenusa pusilla in Rhode Island. We have subsequently followed the expansion of this parasitoid distribution throughout southern New England and the increase in parasitism rate. Populations of this pest have declined to a point that we saw no damage from this pest in Rhode Island in the spring of 2004.
Impacts
We expect Tetrastichus setifer to become permanently established at release sites and to begin spreading throughout southern New England. We also expect to establish at least one of the two ichneumonid species we have released and to see lily leaf beetle populations decline as a result of this research. Cypress spurge and purple loosestrife populations should continue to decline as a consequence of natural dispersal of established biological control agents.
Publications
- Casagrande, R.A. and M. Kenis. 2004. Evaluation of lily leaf beetle parasitoids for North American introduction. Pgs. 121-137. IN Van Driesche, R.G. and Reardon, R. Editors. Assessing host ranges for parasitoids and predators used for classical biological control: a guide to best practice. USDA Forest Service Publication FHTET-2004-03. Morgantown, WV.
- Casagrande, R.A., G. Balme, and B. Blossey. 2003. Rhizedra lutosa, a naural enemy of Phragmites australis in North America. Estuaries. 26: 6002-6006.
- Shrewsbury, P.M., J.H. Lashomb, J.M. Patts, and R.A. Casagrande. 2004. The influence of flowering plants on herbivore and natural enemy abundance in ornamental landscapes. J. Ecol. and Environ. Sci. 30: 23-33.
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Progress 10/01/03 to 12/31/03
Outputs
Lily leaf beetle biological control: With USDA permission, we released T. setifer between 2000 and 2002 into research plots at Wellesley MA and Cumberland RI against Lilioceris lilii. We have recovered successfully overwintered T. setifer for two seasons since our last release in Wellesley, and in the one season following release in Cumberland. For the past two seasons T. setifer has parasitized approximately 75% of the seasonal population of fourth instars in the Wellesley plot and peak larval densities have declined to 1/3 of their levels prior to release (Gold 2003). We have also completed host specificity testing and received release permits for Lemophagus errabundus and Diaparsis jucunda; two ichneumonid species that supplement the activity of T. setifer against L. lilii in Europe. In 2003 we released all three parasitoid species in RI, MA, NH, and ME, selecting release sites by matching the European climate where each parasitoid predominates. High parasitism
among L. lilii larvae indicates that many of these releases were successful and it is likely that we will find that T. setifer successfully overwintered in two new locations next spring: Hudson, NH, and Bridgton, ME. We recovered Lemophagus errabundus from 1 of 3 release sites in 2003 and Diaparsis jucunda at 2 of 3 sites. We plan further releases of all 3 species next season. Cypress spurge biological control: We monitored cypress spurge and the biological control agent, Aphthona flava, in 10 previous release sites. We are finding excellent spurge suppression in 6 of these sites and fair suppression in 2. Two other sites have yet to experience significant suppression. We collected and released about 2800 Aphthona flava beetles at 4 Rhode Island sites to augment earlier releases. We also sent 1200 beetles to colleagues in Long Island, New York, to control a cypress spurge problem on a Nature Conservancy property. We continue to look for potential Aphthona flava release sites in Rhode
Island; particularly looking for cypress spurge infestations in pastures and farm land. Information on this program is available through our website (http://www.uri.edu/cels/pls/biocontrol/index.html). Purple loosestrife biological control: There were four initial release sites of Galerucella spp. in the Rhode Island program for biological control of purple loosestrife. In 2003 two sites show significant impact of the Galerucella release. At one site, in Providence RI, there is a noticeable increase in native plant species in the wetland where Galerucella adults were released. The purple loosestrife plant population has also diminished, and the plants that remain are stunted, and produce fewer flowers. Information on this program is available on our website: (http://www.uri.edu/cels/pls/biocontrol/index.html).
Impacts
We expect Tetrastichus setifer to become permanently established at release sites and to begin spreading throughout southern New England. We also expect to establish at least one of the two ichneumonid species we have released and to see lily leaf beetle populations decline as a result of this research. Cypress spurge and purple loosestrife populations should continue to decline as a consequence of natural dispersal of established biological control agents.
Publications
- Gold,M. 2003. BIOLOGICAL CONTROL OF THE LILY LEAF BEETLE, LILIOCERIS LILII IN NORTH AMERICA. Ph.D. Dissertation. University of Rhode Island.
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