Location: Beneficial Insects Introduction Research Unit
2018 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 U.S. and are increasing in other regions such as California and southeastern states where their impact is also increasing. ARS-Newark continued to provide technical support to cooperators across the U.S. for sentinel surveys to monitor parasitism of H. halys by resident native stinkbug parasitoids in different crop systems, including survey protocols and identification of specimens. Similar training was provided for new cooperators who will be working with spotted lanternfly, Lycorma delicatula, a potential pest of grapes and tree fruit. Foreign exploration was again conducted during June of 2018 in China (Shandong and Shaanxi provinces and Beijing) for natural enemies of the lantern fly. Foreign collections focused 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 U.S. to the Beneficial Insects Introduction Research Unit (BIIRU) quarantine facility for further studies. At BIIRU larval dryinids emerged from many of these parasitized nymphs and have formed cocoons, which will be held for overwintering studies. 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 initiated. Research was conducted to determine the potential impact of Asian Trissolcus japonicus on non-target species in the U.S. Residence times of the parasitoid on kairomones (chemical footprints) varied significantly with residence times on H. halys footprints being significantly longer (90-144%) than on spined soldier bug footprints. 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. The results showed that although T. japonicus can detect the chemical footprints of the non-target spined soldier bug, they have a 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. The studies indicate that behavioral and ecological responses will likely moderate and reduce the potential non-target impact of this Asian parasitoid. T. japonicus also parasitized H. halys eggs more than 3 times as much as spined soldier bug eggs in cage studies incorporating a greater level of realism (egg masses on caged plants contaminated by hosts); and this was the case when the parasitoid emerged from either species of stink bugs. Finally, T. japonicus from soldier bug eggs were much smaller than those emerging from H. halys eggs. Smaller parasitoid individuals are likely to be less fit and have lower lifetime reproductive success. Field collections in Asia were made of parasitoids of other stink bug species to document the actual host stink bug range of trissolcus in the native range. The data will support a release petition in preparation and nearing completion. Surveys were continued to monitor the overwinter survival, establishment and spread of the Asian parasitoid of H. halys, trissolcus, japonicus. Discovered in the U.S. in 2014, it was newly found in Pennsylvania and Ohio during 2017, bringing the total known distribution to ten states and D.C. This research addresses objective 1. NACAs with Seoul National University (#58-1926-3-012F) and with the Yunnan Academy of Agricultural Science (#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. Speciality 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. Collections of Asian H. halys were made and provided to cooperators for new research to detect parasitic microsporidians and determine their impact on stink bug populations. This research addresses Objective 2. 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
Biondi, A., Wang, X., Miller, J.C., Miller, B., Shearer, P.W., Zappala, L., Siscaro, G., Walton, V.W., Hoelmer, K.A., Daane, K.M. 2017. Innate olfactory responses of Asobara japonica toward fruits infested by the invasive spotted wing Drosophila. Journal of Insect Behavior. https://doi.org/10.1007/s10905-9636-y.
Hajek, A.E., Solter, L.F., Maddox, J.V., Huang, W., Estep, A.S., Krawcyzk, G., Weber, D.C., Hoelmer, K.A., Sanscrainte, N.D., Becnel, J.J. 2017. Nosema maddoxi sp. nov. (Microsporidia, Nosematidae), a widespread pathogen of the green stink bug Chinavia hilaris (Say) and the brown marmorated stink bug Halyomorpha halys (Stål). Journal of Eukaryotic Microbiology. https://doi.org/10.1111/jeu.12475.
Hopper, K.R., Lanier, K., Rhoades, J.H., Hoelmer, K.A., Meikle, W.G., Heimpel, G.E., O'Neil, R.J., Voetglin, D.G., Woolley, J.B. 2017. Host specificity of Aphelinus species collected from soybean aphid in Asia. Biological Control. 115:55-73. https://doi.org/10.1016/j.biocontrol.2017.09.004.
La-Spina, M., Pickett, C.H., Daane, K.M., Hoelmer, K.A., Blanchet, A., Williams III, L.H. 2017. Effect of exposure time on mass-rearing production of the olive fruit fly parasitoid, Psyttalia lounsburyi (Hymenoptera: Braconidae). Journal of Applied Entomology. 142(3):319-326. https://doi.org/10.1111/jen.12478.
Wang, X., Nance, A., Jones, J., Hoelmer, K.A., Daane, K. 2018. Aspects of the biology and developmental strategy of two Asian larval parasitoids evaluated for classical biological control of Drosophila suzukii. Biological Control. 121:58-65. https://10.1016/j.biocontrol.2018.02.010.
