2013 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 Delaware and New Jersey in a cooperative project with the NJ Dept. of Agriculture. This research addresses objective 3. Field surveys were made with the help of cooperators in several states to obtain specimens of a previously established related species, PERISTENUS DIGONEUTIS, in support of an ongoing retrospective population genetics study of its establishment. This research addresses objective 2. 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 APHELINUS GLYCINES were initiated this year (see complementary project 1926-22000-024-00D). This research addresses objectives 1 and 3. Populations of the brown marmorated stink bug (BMSB) have developed into a significant pest in soybeans and various tree fruits in the eastern and western 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, including identification of specimens. Additional foreign exploration during July and August in China and Korea was conducted to identify BMSB biocontrol agents of the target and Asian non-target stink bugs in support of ongoing host range evaluations and new spotted-wing drosophila natural enemies to enable host range evaluations with cooperators. This research addresses objective 1. Through subordinate projects 1926-22000-026-12R (BIOLOGY, ECOLOGY,A ND MANAGEMENT OF BROWN MARMORATED STINK BUG IN ORCHARD CROPS, SMALL FRUIT, GRAPES, VEGETABLES AND ORNAMENTALS), 1926-22000-026-12R (WHOLE FARM ORGANIC MANAGEMENT OF BMSB AND ENDEMIC PENTATOMIDS THROUGH BEHAVIOR-BASED HABITAT MANIPULATION) and 1926-22000-026-19R (HOST-SPECIFICITY TESTING OF NATURAL ENEMIES OF THE BROWN MARMORATED STINK BUG (BMSB), HALYOMORPHA HALYS (STÅL) (HEMIPTERA: PENTATOMIDAE) support was provided for ongoing host range evaluations for exotic and native natural enemies of the stink bug. This research addresses objective 1. A second workshop on identification of native and exotic BMSB parasitoids was organized to help educate research collaborators and local extension specialists. ARS researchers compiled and updated a master key for the identification of BMSB parasitoids commonly found in North America. This research-related activity addresses objective 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.
Origin of U.S. populations of brown marmorated stink bug identified. The invasive brown marmorated stink bug (BMSB), native to northeast Asia, has become a principal agricultural pest in the US and is responsible for crop failures on many mid-Atlantic farms. Current control efforts rely on heavy insecticide applications because no other options are available. To examine the genetic diversity and identify the source region of the US introductions, ARS researhers at Newark, Delaware sequenced portions of several genes in BMSB from populations in the US, China, South Korea and Japan. We observed high levels of genetic diversity in native Asian populations but very low genetic diversity in introduced US populations, and we traced the origin of US BMSB populations to the Beijing area in China. A single introduction of a very small number of founding individuals explains the invasion history in the US. For effective control of the US populations, our results suggest that surveys for effective natural enemies and for evidence of insecticide resistance in native populations should focus on the Beijing area in China.