Location: Beneficial Insects Introduction Research Unit
2019 Annual Report
Objectives
1: Discover, characterize, identify, evaluate the efficacy, and determine the ecological safety of exotic predators and parasitoids as classical biological control agents of invasive insect pests, including tarnished plant bug, brown marmorated stink bug, and spotted wing drosophila, and may include other new invasive species, such as kudzu bug.
Sub-objective 1A: Discovery
Sub-objective 1B: Characterization and identification
Sub-objective 1C: Evaluation and risk assessment
2: Develop an improved understanding of factors and processes that influence the successful establishment of introduced biological control agents, such as climate adaptation, release methodologies, genetic variation in source and founder populations, using natural enemies of current target pests as model systems.
Sub-objective 2A: Conduct retrospective analyses of current/past biological control programs (where appropriate).
Sub-objective 2B: Conduct laboratory and field studies of selected biological traits and ecological requirements relevant to the establishment and efficacy of the target biological control agents.
3: Prepare (with collaborators, when appropriate and necessary) petitions to regulatory agencies for field release of candidate agents, conduct field releases for establishment of new agents, and monitor and evaluate the impact of these natural enemies on target pest populations and on non-target species in the field.
Sub-objective 3A: Develop and submit a petition for release that describes the importance of the target pest and the efficacy and safety of the candidate biocontrol agent; and participate in the regulatory decision process as needed.
Sub-objective 3B: Conduct releases and post-release monitoring (with cooperators when necessary) of permitted natural enemies.
Approach
Classical (importation) biological control is a pest management technology that is environmentally safe and sustainable. This project focuses on discovery, evaluation, and establishment of classical biological control agents of selected agricultural pests in the U.S. Previous research continued into this project addresses as targets tarnished plant bugs, brown marmorated stink bug; and spotted wing drosophila. New targets may be added at any time according to national need.
To address objective (1) we will conduct foreign exploration in Asia and other regions as needed to discover, identify and evaluate the biology, ecology, and efficacy of exotic predators and parasitoids as classical biological control agents of the targeted pests. Agents discovered in exploration will be returned to our laboratory and identified using the best available morphological characters in conjunction with molecular sequence data, and evaluated in our quarantine facility for efficacy by measuring attack rates, reproductive output and development rates, and for host specificity by testing both close relatives to target hosts and progressively more distantly related species under choice and no-choice conditions.
Objective (2) will address the role of environmental factors such as climate and photoperiod or inherent genetic variability in determining establishment success. Using a parasitoid of tarnished plant bug that established in some regions of the US but not others as the model subject, we will characterize the genetic variability of populations established in the US and their relation to genetic source populations in Europe. Using parasitoids of any or all target pests, we will test the influence of differing environmental factors such as temperature, soil moisture and photoperiod regimes on parasitoid survival in environmental growth chambers and comparative field exposures.
To address objective (3) we will prepare petitions for field release of qualified candidate agents of all target pests determined to be both effective and safe, based on satisfactory results of evaluation studies. These will be submitted to technical advisory panels and APHIS, in collaboration with relevant project partners as necessary. Supplemental research will be conducted to provide additional information if requested by APHIS. Once permits are received we will participate with cooperators as needed in conducting releases and post-release monitoring of the natural enemies. Where possible the releases will be designed to compare different geographic populations or genetic accessions of the agent for differences in climate adaptation, efficacy or other behavioral characteristics.
Progress Report
Populations of the brown marmorated stink bug (H. HALYS) have been significant pests in soybeans, vegetables, nut and various tree fruits in the eastern and northwestern United States for the past decade, and their impact is still increasing in other regions such as California and southeastern states. ARS Newark continued to provide technical support to cooperators across the United States for sentinel surveys to monitor parasitism of H. HALYS by resident native stinkbug parasitoids in different crop systems, including survey protocols, workshops (annual workshops were held in January 2019 in Florida and in April 2019 in Montpellier, France in association with the ARS European Biological Control Laboratory (EBCL) and identification of specimens (Objectives 1B and 3B; Agreement no. 58-8010-7-012). Similar training was provided for new cooperators who have begun regional research on spotted lanternfly, LYCORMA DELICATULA, a newly invasive pest of grapes, hops and potentially of tree fruit. Foreign exploration was conducted for a fourth year during June of 2019 in China (Henan, Jiangsu and Shandong provinces and Beijing) for natural enemies of the lantern fly. Foreign collections in 2019 focused again on natural enemies of lanternfly nymphs, in particular the dryinid wasp, DRYINUS BROWNI. Adult wasps attack young nymphs of lanternfly in early summer. Difficult to spot in the field as adults, a number of wasps were recovered from sticky bands wrapped around trees to trap lanternfly nymphs and were collected for further taxonomic research and identification. Parasitized lanternfly nymphs were found in substantial numbers at several of the surveyed sites, and several hundred live parasitized second and third instar nymphs were successfully hand-carried back to the United States to the Beneficial Insects Introduction Research Unit (BIIRU) quarantine facility for further studies. At the BIIRU, larval dryinids emerged from many of these parasitized nymphs collected during the previous summer of 2018 and were placed into winter temperature regimes and held for overwintering studies still in progress (Objective 2B). Live parasitoids emerged from June 2019 collections will be added to this research. A series of adult wasps from 2018 collections were sent to a dryinid taxonomist for confirmation of their identity. This lanternfly research contributed to Objectives 1A and 1B. Host range studies of the Asian egg parasitoid ANASTATUS ORIENTALIS which attacks lanternfly eggs was initiated through Agreement #58-22000-6-009 with the University of Delaware and APHIS PPQ cooperators which funds a University of Delaware graduate student to collect and rear a range of nontarget planthoppers for host range suitability and taxonomic studies of native United States ANASTATUS egg parasitoids (Objective 1C). Further field collections of TRISSOLCUS parasitoids of Asian stink bugs were obtained for genetic studies in collaboration with the EBCL and the Systematic Entomology Laboratory (Objective 2A).
Laboratory research on the diapause requirements and climatic suitability for different regions of the U.S. of GANASPIS BRASILIENSIS, a larval-pupal parasitoid of the spotted wing drosophila DROSOPHILA SUZUKII, was continued in 2019 (Objective 2B). Research was conducted in the field and the laboratory to assess the potential impact of Asian TRISSOLCUS JAPONICUS on non-target species in the United States. Previous research on the behavioral response of the parasitoid TRISSOLCUS JAPONICUS to its host and to non-target kairomones (chemical footprints) was expanded. The response varied significantly, with residence times on H. HALYS footprints being significantly longer than on spined soldier bug footprints; this response was not significantly different for exposure to either female and to male host stinkbugs. T. JAPONICUS remained the shortest amount of time on leaves that were not contaminated with host chemical footprints. These trends were also reflected in walking velocity of parasitoids, with parasitoids walking fastest on untreated clean leaves and slowest on leaves contaminated by H. HALYS l footprints. Furthermore, the wasp responded in similar manner to immature nymphal stages of H. HALYS, but not to immature spined soldier bugs. The results showed that although T. JAPONICUS can detect the chemical footprints of the adult non-target spined soldier bug, they have a much stronger behavioural response to H. HALYS, and thus are likely to spend more time in searching for stink bug eggs on plants contaminated by H. HALYS. Extracts of the kairomones were isolated and identified in collaboration with the ARS Invasive Insect Biocontrol and Behavior Lab in Beltsville, Maryland. Two compounds, E-2-decenal and tridecane, appear to be the major components of the BMSB kairomone that elicit a TRISSOLCUS response. The studies indicate that behavioral and ecological responses will likely moderate and reduce the potential non-target impact of this Asian parasitoid (Objective 1C). A similar approach was used to assess the behavioral response of the lanternfly egg parasitoid ANASTATUS ORIENTALIS to lanternfly eggs (manuscript submitted to journal). Field collections in Asia were continued of parasitoids of other stink bug species to document the actual host stink bug range of TRISSOLCUS in the native range. The data is important for a United States release petition nearing completion. A similar petition was submitted in FY19 and is undergoing regulatory review for field releases in Canada, for which we contributed our research data (Objective 3A). Surveys were continued to monitor the overwinter survival, establishment and spread of TRISSOLCUS JAPONICUS, the Asian parasitoid of H. HALYS. Discovered in the United States in 2014, it was newly found in Michigan and California during 2018, bringing the total known adventive distribution to twelve U.S. states, the District of Columbia, and several adjacent Canadian provinces. It has also now been found adventively in Europe. This research addresses Objective 1. In Delaware, the adventive TRISSOLCUS was redistributed within the state to accelerate its establishment and expand its range of occurrence (Objective 3B). Non Assistance Cooperative Agreements with Seoul National University (Agreement #58-1926-3-012F) and with the Yunnan Academy of Agricultural Science (Agreement #58-0212-3-006F with ARS/EBCL) provided local assistance in Asia for foreign exploration for natural enemies of H. HALYS and DROSOPHILA SUZUKII and fund continuing studies on natural enemies of these invasive pests in their native range. Through subordinate projects 8010-22000-030-01R (Management of Brown Marmorated Stink Bug (BMSB) in U.S. Specialty Crops) and 8010-22000-026-29I (CLASSICAL BIOLOGICAL CONTROL OF THE BROWN MARMORATED STINK BUG) extramural support was received for ongoing biological studies and host range evaluations for exotic and native natural enemies of the stink bug. 8010-22000-030-10R (Sustainable Spotted Wing Drosophila Management for United States Fruit Crops - Coordinated Agricultural Project) provides support for foreign exploration and host range testing of candidate natural enemies of spotted wing drosophila. This research addresses Objectives 1 and 3. The overall impact of the research is that producers will have new biological control agents available that will help them manage key insect pests by reducing chemical pest management inputs, thereby maximizing profits and sustaining yield.
Accomplishments
Review Publications
Kaser, J.M., Akotsen-Mensah, C., Talamas, E.J., Nielsen, A.L. 2018. First report of Trissolcus japonicus parasitizing Halyomorpha halys in North American agriculture. Florida Entomologist. 101(4): 680-683. https://doi.org/10.1653/024.101.0406.
Buffington, M.L., Talamas, E., Hoelmer, K.A. 2018. Team Trissolcus: Integrating taxonomy and biological control to combat the brown marmorated stink bug. American Entomologist. 64:224-232.
Giorgini, M., Wang, X., Wang, Y., Chen, F., Zhang, H., Chen, Z., Cascone, P., Formisano, G., Carvalho, G.A., Buffington, M.L., Hoelmer, K.A., Guerrieri, E. 2018. Exploration for native parasitoids of Drosophila suzukii in China reveals a diversity of parasitoid species and narrow host range of the dominant parasitoid. Journal of Pest Science. 92:509-522. https://doi.org/10.1007/s10340-018-01068-3.
Hopper, K.R., Oppenheim, S.J., Kuhn, K.L., Lanier, K., Hoelmer, K.A., Heimpel, G.E., Meikle, W.G., O'Neil, R.J., Voegtlin, D.G., Wu, K., Woolley, J.B., Heraty, J.M. 2019. Counties not countries: Variation in host specificity among populations of an aphid parasitoid. Evolutionary Applications. 12(4):815-829. https://doi.org/10.1111/eva.12759.
Lee, J.C., Wang, X., Daane, K.M., Hoelmer, K.A., Isaacs, R., Sial, A., Walton, V. 2019. Biological control of spotted-wing drosophila (Diptera: Drosophilidae) - Current and pending tactics. Journal of Integrated Pest Management. 10(1):1-9. https://doi.org/10.1093/jipm/pmz012.
Sabbatini Peverieri, G., Talamas, E., Bon, M., Marianelli, L., Bernardinelli, I., Malossini, G., Benvenuto, L., Roversi, P., Hoelmer, K.A. 2018. Two Asian egg parasitoids of Halyomorpha halys (Stal) emerge in Northern Italy : Trissolcus mitsukurii (Ashmead) and Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae). Journal of Hymenoptera Research. 67: 37-53. 2018. https://doi.org/10.3897/jhr.67.30883.
Stahl, J., Tortorici, F., Pontini, M., Bon, M., Hoelmer, K.A., Marazzi, C., Tavella, L., Haye, T. 2019. First discovery of adventive populations of Trissolcus japonicus (Ashmead) in Europe. Journal of Pest Science. 92:371-379. https://doi.org/10.1007/s10340-018-1061-2.
