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Funded Project

Funding Program: IPM Partnership Grants

Project Title: Enhancing Floral Resources for Conservation Biological Control in Urban Landscapes

Project Director (PD): Ana Legrand [1]

Lead State: CT Lead Organization: University of Connecticut

Undesignated Funding: $30,000

Start Date: Apr-01-2009 End Date: Mar-31-2010

No-Cost Extension Date: Jun-30-2012

Pests Involved: Japanese beetles, Oriental beetles

Site/Commodity: urban, landscapes, turfgrasses, community

Area of Emphasis: biocontrol, biological control, conservation, invasive insects

Summary: The most damaging turf insect pests are scarab beetle larvae or white grubs. During 1920's and 1930's USDA entomologists imported Tiphia vernalis Rohwer from Korea and Tiphia popilliavora Rohwer. (Hymenoptera: Tiphiidae) from Japan for Japanese beetle control. Wasp releases were made throughout the northeastern United States. The primary target of these releases was the invasive Japanese beetle. However, T. vernalis and T. popilliavora can attack the Oriental beetle as well. The goal of the project is to determine if conservation biological control through the addition of floral resources can be used to enhance Tiphia spp. parasitism of Oriental and Japanese beetle larvae. The objectives of the project are: 1) to assess the parasitism rates of T. popilliavora on Japanese and Oriental beetle larvae; 2) to screen several flowering plant species that could be used to provide nectar resources to Tiphia vernalis during May and June; 3) to screen several flowering plant species that could be used to provide resources to Tiphia popilliavora during August and September; and 4) to test the hypothesis that the presence of food plants for Tiphia wasps will increase parasitism of Japanese beetle and Oriental beetle larvae by these parasitoids. The criteria for selection of floral resource plants will include that they are not attractive to the pest beetles. Results from this project will indicate which plant species the public can use to promote conservation biological control in residences or in public landscapes. The long term impact from this project will be in safeguarding human health and the environment. The proposed approach addresses an important IPM issue of developing more biological control options against the Oriental and Japanese beetles. Objectives: The objectives of the project are: 1) to assess the parasitism rates of T. popilliavora on Japanese and Oriental beetle larvae; 2) to screen several flowering plant species that could be used to provide nectar resources to Tiphia vernalis during May and June; 3) to screen several flowering plant species that could be used to provide resources to Tiphia popilliavora during August and September; and 4) to test the hypothesis that the presence of food plants for Tiphia wasps will increase parasitism of Japanese beetle and Oriental beetle larvae by these parasitoids. The criteria for selection of floral resource plants will include that they are not attractive to the pest beetles. Results from this project will indicate which plant species the public can select to promote conservation biological control in their residences or in public landscapes. Conservation biological control of Tiphia wasps using floral resources will be a different tool promoted in our area that could be implemented in a short time leading to less insecticide use in urban landscapes. The long term impact from this project should be in safeguarding human health and the environment. The pests and setting addressed in this proposal are found throughout the Northeastern region and the proposed approach will address an important IPM issue of developing more biological control options against the Oriental and Japanese beetles. Proposal

Final Report:

Outcomes The results of the project are summarized below. Information has been generated on the type of plants that attract the two species of Tiphia wasps that attack Japanese and oriental beetles. In addition, tests were done to evaluate the feeding preferences of Japanese beetles on some of these plants. Lastly, the project also generated needed information on the distribution and timing of activity of these wasps in two Northeast states. Objective 1. Evaluation of ornamental plants as sources of nectar for Tiphia vernalis In 2009, no significant differences were found in the mean cumulative number of wasps counted during hourly observations on the peonies, V. dentatum Blue Muffin and S. canadensis York. Tiphia wasps were observed feeding off the extrafloral nectar on all the plants selected (Fig. 1 in full report). A second set of plants composed of various elderberries and viburnums was also evaluated. Significant differences were found in the mean cumulative number of wasps found on the plants (Fig. 2 in full report). V. dentatum Blue Muffin attracted the most wasps followed by S. canadensis York. The other elderberries or viburnums tested did not attract as many wasps. In 2010, there were significant differences observed in the mean cumulative number of wasps counted during hourly observations on the peonies, V. dentatum Blue Muffin and on S. canadensis York. All of the three peony cultivars tested attracted the most wasps as compared to the other plants (Fig.3 in full report). Objective 2. Evaluation of ornamental plants as host plants for pest scarab beetles Very few Japanese beetles were observed on the selected ornamental plants during the field evaluation. Most of the beetles were observed on V. dentatum Blue Muffin which received most of the feeding injuries (Table 1 in full report). Nevertheless, the degree of injury on this viburnum was very small relative to other ornamentals that could have more than 60% of leaves with feeding injuries. The evaluation within the cages confirmed this result. The viburnum received the most feeding injury within the cages followed by the elderberry York. This increased level of injury is likely due to the higher pest pressure placed on the plant (100 beetles per cage). The peonies were free of feeding injuries both in the open field and caged experiments. The grub samples obtained around the plants indicated the presence of oriental and Asiatic Garden beetle grubs only. Other species were not found. The numbers of oriental beetle and Asiatic Garden beetle grubs collected from nearby each ornamental plant type were not significantly different (Table 2 in full report). Objective 3. Evaluation of ornamental plants as sources of nectar for Tiphia spp. Of the plants selected only the wild carrot attracted a significant number of Tiphia spp. individuals in 2009 and 2010 tests. In 2009, the yarrow selections and the ornamental goldenrod did not attract Tiphia wasps except for two times at each location when one wasp was observed on one of the yarrows (Figs. 4 and 5 in full report). In spite of not attracting Tiphia spp., the ornamental plants selected did attract a variety of beneficial insects including several types of syrphid flies, bees and bumble bees. The orders most often represented in the data collected were the hymenoptera and diptera. In conclusion, the wild carrot attracted a high number of Tiphia wasps often as high or higher in number compared to all of the other hymenoptera observed visiting those flowers. Field observations indicate that Tiphia spp. are commonly found on wild carrot plants and occasionally on wild goldenrods. In this experiment, the ornamental goldenrod S. cutleri did not attract any Tiphia wasps. In 2010, the yarrow and the apiaceae species selected did not attract any Tiphia wasps. These results follow the same pattern observed in 2009 when only the wild carrot attracted the most Tiphia over any of the other ornamental plants tested (Figs. 6 and 7 in full report). Wild carrot is considered a weed so its usefulness for conservation biocontrol in settings like golf courses or public landscapes might be limited. However, it is an aesthetically pleasing plant (its popular name is Queen Annes Lace) that some homeowners or other private entities might find useful for conserving Tiphia wasps present in summer time. Objective 4. Tiphia vernalis and T. popilliavora surveys T. vernalis were found in all of the Massachusetts counties and in two out of three New Hampshire counties visited (Table 3 in full report). In 1950, the USDA had monitored the wasp presence in three of the five counties were T. vernalis had been originally released. At that time, wasps were not recovered from these locations. Wasps were not collected from Cheshire county in New Hampshire but only one location was visited in this county. Nevertheless, wasps were found in the neighboring Hillsborough county, NH to the east and Worcester county, MA in the south. T. vernalis adults were observed weekly in Ware, Spencer and Athol, MA. Wasps were observed starting in May 14 and the last adults observed in Ware and Athol were recorded on June 19th and June 26th, respectively. T. popilliavora wasps were found in three of the seven Massachusetts counties visited (Table 4 in full report). The timing for the survey could have influenced the results since collections started in August 20 and the survey dates in September could have been late for 2012 wasp activity. However, it is significant to note that the species is found in northernmost Massachusetts locations such as Athol in Worcester county and Methuen in Essex county. The results from the New Hampshire survey indicate that T.popilliavora is present in all of the counties visited along the northern border with Massachusetts (Table 4 in full report). The 2012 survey documents the natural spread of this wasp to northern locations where it had not been released by the USDA. Outputs The results from the project have been reported through various publications and presentations including the following that are in print or have been presented. Other materials are in preparation. Legrand, A. 2009. Drubbing Grubs Naturally. TurfGrass Trends Sept. 1, 2009. Pg. 49-52. Legrand, 2009. Evaluation of landscape ornamental plants as nectar plants for Tiphia vernalis and as host plants for pest scarab beetles. p. 73-76. In K. Guillard (ed), 2009 Annual Turfgrass Research Report, College of Agriculture and Natural Resources, University of Connecticut. Legrand, 2009. Evaluation of ornamental plants as nectar sources for summer Tiphia. p. 77-79. In K. Guillard (ed), 2009 Annual Turfgrass Research Report, College of Agriculture and Natural Resources, University of Connecticut. Legrand, 2010. Evaluation of landscape ornamental plants as nectar plants for Tiphia vernalis and as host plants for pest scarab beetles. Entomological Society of America EB Meeting, March 2010. Annapolis, MD. Legrand, A. 2010. Evaluation of landscape ornamental and herb plants as nectar sources for Tiphia parasitoid wasps. In K. Guillard (ed), 2010 Annual Turfgrass Research Report, College of Agriculture and Natural Resources, University of Connecticut. Legrand, A. 2010. Color preference of the Japanese beetle parasitoid Tiphia vernalis. In K. Guillard (ed), 2010 Annual Turfgrass Research Report, College of Agriculture and Natural Resources, University of Connecticut. Legrand, A. 2010. Evaluation of landscape ornamental plants as nectar plants for Tiphia vernalis. UConn Turfgrass Field Day Research Summaries. July 2010. College of Agriculture and Natural Resources, University of Connecticut. Legrand, A. 2010. Evaluation of landscape ornamental plants as host plants for pest scarab beetles. UConn Turfgrass Field Day Research Summaries. July 2010. College of Agriculture and Natural Resources, University of Connecticut. Legrand, A. 2010. Evaluation of ornamental plants as nectar sources for summer Tiphia parasitoid wasps. UConn Turfgrass Field Day Research Summaries. July 2010. College of Agriculture and Natural Resources, University of Connecticut. Legrand, A. 2010. Evaluation of landscape ornamental plants as nectar sources for beneficial Tiphia wasps. UConn Turfgrass Field Day. July 20 2010, Storrs, CT. Legrand, A. 2010. Parasitism rates of Tiphia vernalis in Connecticut. IPM Program. Biocontrol of White Grubs Fact Sheets. August 2010. Legrand, A. 2010. Evaluation of ornamental plants as nectar sources for Tiphia parasitoids. Entomological Society of America Annual Meeting. San Diego, CA. December 2010. Legrand, A. 2011. Evaluation of ornamental plants as nectar sources for Tiphia parasitoids. Connecticut Conference on Natural Resources, Storrs, CT. March 2011. Legrand. A. 2011. May is the time for the Spring Tiphia. UConn Turfgrass Update. May 2011. Legrand, A. 2011. Tiphia parasitic wasps take on Japanese and oriental beetle grubs. Home & Garden News, May/June 2011. Home and Garden Education Center. College of Agriculture and Natural Resources, University of Connecticut. Legrand, A. 2012. Use of peonies to increase Tiphia vernalis parasitism on white grubs. Turfgrass Field Day Research Summaries. July 2012. College of Agriculture and Natural Resources, University of Connecticut. Legrand, A. 2012. Survey of Tiphia parasitoids of the Japanese and oriental beetles in Massachusetts and New Hampshire. Display Presentation, Plant-Insect Ecosystem Section. Entomological Society of America Annual Meeting. Knoxville, Tennessee. November, 2012. Information on Tiphia wasps and their nectar plants has been provided through educational displays at public events such as: Celebrating Agriculture Fair, Cornucopia Fest, IPM for the home landscape, Berlin Library Spring Gardening Series; and Biological control of the Japanese beetle, Master Gardener Program Farm Tour.

Impacts The project results have increased our understanding of Tiphia wasps and of the type of plants that can be used to attract them. First, peonies consistently attracted Tiphia vernalis (spring Tiphia) and are the best choice of plants for this purpose. The viburnum and elderberry do not attract as many wasps and Japanese beetles feed on these plants to greater extent than on peonies. Based on previous studies and on this project, one can conclude that the Tiphia vernalis will utilize extrafloral nectaries as a source of nectar and it is not likely to feed directly from flowers as other beneficial wasps do. Thus, peonies will be a good choice for persons wishing to provide nectar sources for the Spring Tiphia and aid in their conservation. The peonies Big Ben, Festiva, Bowl of Beauty and Sarah Bernhardt will be good selections for a landscape design that included plants to attract and feed T. vernalis. These plants also will not suffer from Japanese beetle feeding. Second, the results of evaluations involving summer Tiphia species clearly showed that only wild carrot attracts these wasps out of several plants tested. In addition to the above, we have new information on the distribution of these wasps in the Northeast. We have confirmation that both T. vernalis and T. popilliavora are found in several Massachusetts counties and are found as far north as in Hillsborough and Rockingham counties in New Hampshire. The knowledge generated by the project is being distributed to the target audiences (homeowners, groundskeepers, landscape managers, extension staff, etc) through publications, presentations and public displays. The goal is to have audiences learn about Tiphia wasps and other natural enemies of scarab beetles and how to conserve them. The long term impact will be to safeguard human health and the environment by providing a diverse set of tactics that can be promoted for IPM of scarab beetle pests such as the Japanese and oriental beetles.

Report Appendices Legrand Partnership Grant Full Report [PDF]

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