2012 Annual Report
1a.Objectives (from AD-416):
1: Discover, identify and evaluate the biology, ecology, and efficacy of exotic predators and parasitoids as classical biological control agents of invasive arthropod pests of agricultural crops. Determine their ecological safety for release as classical biological control agents. Current targets include soybean aphid, tarnished plant bug, brown marmorated stink bug, and spotted wing drosophila.
Sub-objective 1A: Discovery.
Sub-objective 1B: Identification.
Sub-objective 1C: Evaluation and risk assessment.
2: Develop an improved understanding of mechanisms that influence successful establishment of introduced biological control agents, using parasitoids and predators of current target pests such as tarnished plant bug 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 biological control agents.
3: With collaborators, conduct field releases, monitor for establishment and evaluate the impact of natural enemies on target pest populations (such as soybean aphid, tarnished plant bug, and brown marmorated stink bug) as well as non-target effects 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.
Sub-objective 3B: Participate in the regulatory decision process as needed.
Sub-objective 3C: Participate with cooperators in conducting releases (with permits from State and APHIS) and post-release monitoring of the natural enemy.
1b.Approach (from AD-416):
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 mirid plant bugs, soybean aphid, and brown marmorated stink bug; and a fourth target, spotted wing drosophila, has been added for evaluation of its biological control potential. 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 U.S., but not others as the model subject, we will characterize the genetic variability of populations established in the U.S. and their relation to genetic source populations in Europe. Also using lygus parasitoids, 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.
To combat a key multi-crop pest, continued field releases of the tarnished plant bug parasitoid PERISTENUS RELICTUS were made in the MidAtlantic states in a cooperative project with the NJ Dept. of Agriculture. Field surveys were made in several states to obtain specimens of a previously established related species, PERISTENUS DIGONEUTIS, in support of a retrospective population genetics study of its establishment. Since its establishment in North America a decade ago the invasive soybean aphid has become a key pest of soybeans. Field releases by cooperators in the Midwestern states of the soybean aphid parasitoid BINODOXYS COMMUNIS are ongoing. Three additional species in the genus APHELINUS new to science discovered in foreign exploration were described and named and, based on quarantine evaluation results, petitions for field release of two of the species in the genus APHELINUS were approved. Populations of the brown marmorated stink bug have developed into a significant pest in soybeans and various tree fruits in the eastern U.S. and are still spreading to other states. ARS Newark provided technical support to cooperators for expanded sentinel surveys to monitor parasitism of BMSB by resident native stinkbug parasitoids in different crop systems. Additional foreign exploration during late summer in Asia was planned to obtain new BMSB biocontrol agents for ongoing host range evaluations.
New species of biological control agents have been approved for field release against soybean aphid. Soybean aphid has become a major pest in the US, damaging as many as 70 million acres of soybeans per year. Biological control using Asian parasitoids specific to soybean aphid is a promising approach for control of this invasive soybean pest. Exploration was conducted in Asia by ARS researchers at Newark, Delaware, to find natural enemies of soybean aphid. Three species that are new to science were discovered, and research at Newark identified these species as effective and safe for introduction. Field releases of two of these natural enemies recently received regulatory approval. Introduction of these biological control parasitoids will help to reduce damage by soybean aphid to US soybeans.
Day, W.H., Hoelmer, K.A. 2012. Impact of the introduced parasitoid Peristenus digoneutis (Hymenoptera: Braconidae) on tarnished plant bug (Hemiptera: Miridae) infesting strawberries in northwestern New Jersey, USA. Biocontrol Science and Technology. 22:975-979.