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United States Department of Agriculture

Agricultural Research Service

Research Project: Biocontrol of Invasive Pests Such As Emerald Ash Borer and Quarantine Services

Location: Beneficial Insects Introduction Research

2013 Annual Report


1a.Objectives (from AD-416):
This project seeks to reduce populations of EAB without adverse effects on the environment via biological control approaches relevant to the knowledge base of the target pest and its natural enemies, and has three objectives representing different aspects and/or stages of classical biological control research and development:

1: Explore for natural enemies (parasitoids) of EAB in its native range and evaluate their suitability for introduction. 1a - Explore for parasitoids of EAB in its native range. 1b - Evaluate the suitability of discovered parasitoid for introduction to North America for EAB control. 2: Evaluate impacts of extant (indigenous) and previously introduced parasitoids on populations of EAB, particularly in northeastern and/or Midwestern states. 3: Develop effective mass rearing technologies for hymenopteran parasitoids of EAB and other invasive pests. 3a - Determine the key life history parameters of the concerned parasitoid species. 3b - Determine the optimal host stage and host density (or host to parasitoid exposure ratio). 3c - Determine the optimal environmental conditions for adult parasitoid survival, oviposition, and progeny development.


1b.Approach (from AD-416):
We will conduct foreign exploration for parasitoids of EAB in its native range including the Far East region of Russia, Korea, and China. In each of the study areas, five to 10 sites will be selected for EAB parasitoid exploration covering a wide range of habitats including upland and riparian natural forests with Oriental Fraxinus spp. and plantations of both North American and Oriental Fraxinus spp. At each selected site, ash trees will be examined for signs of EAB infestation in late summer, fall, and/or spring. Ash trees exhibiting any signs of infestation will then be felled, and debarked for sampling different immature stages of EAB and associated parasitoids. Promising parasitoid species collected from the foreign exploration will then be tested in quarantine against a list of North American Native wood-boring beetles to determine their host specificity. After completing host range studies, we will develop an environmental impact assessment (EIA) of proposed releases of the promising parasitoids, which will be selected based on their efficacy against EAB in the native range (Asia) and host specificity against North American native (nontarget) wood boring beetles, and submit the EIA to USDA APHIS (or other regulatory authorities) for review and approval. Once the selected candidate species are cleared for release by Federal and State regulatory authorities, efforts will be directed towards field release and establishment along with development of mass-rearing technologies and impact assessment.


3.Progress Report:
EMERALD ASH BORER RESEARCH: Additional field surveys of North American green ash (Fraxinus pennsylvanica Marshall) and/or Oriental ashes (F. mandshurica Rupr. and F. rhynchophylla Hance and) were conducted in September of 2012 in the Vladivostok regions of Russia and Northeast China (Heilongjiang Province). Three EAB parasitoids (Spathius galinae, Atanycolus nigriventris, and Oobius agrili) were collected from the survey and subsequently imported to the USDA BIIR quarantine facility. Host specificity testing with one of the parasitoids (S. galinae) was completed and petition for environmental releases of this parasitoid has been submitted to USDA APHIS for regulatory review and approval.

In collaboration with USDA Forest Service (FS) and Animal and Plant Health Inspection Service (APHIS), Maryland Department of Agriculture, University of Maryland, and University of Massachusetts, six study sites in Michigan and four sites in Maryland have been continuously surveyed for evaluation of impacts of three previously introduced parasitoids (Tetrastichus planipennisi, S. agrili, and O. agrili). Results from the field study in Michigan showed that by the fall of 2012, 92% and 83% of sampled trees had one or more broods of T. planipennisi (released between 2007 – 2010) in the parasitoid-release and control plots. The rates of EAB larval parasitism by T. planipennisi were 21.2% in the parasitoid-release plots and 12.8% for the control plots by the fall of 2012. In contrast, no parasitism by S. agrili was detected in both release and control plots, and low rates (2 – 10%) of parasitism by O. agrili was primarily found in the parasitoid-release sites. These findings demonstrate that T. planipennisi is established in southern Michigan and that its populations are increasing and expanding. Data from Maryland field studies also showed that the biocontrol agent T. planipennisi was frequently recovered with a rate of parasitism ranging from 5 – 15% from several release sites, where the adult parasitoids had been released between 2010 and 2011. However, no parasitism by S. agrili or O. agrili was recovered from field samples in spring of 2013. This indicates that more time and releases are needed in Maryland for those newly introduced biocontrol agents to establish increasing populations on EAB.

QUARANTINE SERVICES: A total of 78 permitted consignments were received by the Quarantine Facility, consisting of 15,117 pest specimens, and 688 parasitoids in the genus Oobius. A total of 39 outgoing shipments, 1430 pest specimens, and 11,365 parasitoids in 6 genera. Five identification requests and two paratypes of Trissolcus halyomorphae were provided to the ARS Systematic Entomology Laboratory.


4.Accomplishments
1. Successful introduction and establishment of the larval parasitoid (T. planipennisi) in Michigan for classical biological control of the invasive emerald ash borer (EAB). The emerald ash borer, Agrilus planipennis Fairmaire, is a serious invasive beetle responsible for widespread ash mortality in North America. Between 2007 and 2010, Tetrastichus planipennisi Yang is a gregarious larval endoparasitoid native to China and has been introduced to the United States since 2007 for classical biological control of this pest. Adults of this parasitic wasp (3,311 – 4,597 females and about 1500 males per site) were released into each of six forest sites in three counties (Ingham, Gratiot, and Shiawassee) of southern Michigan. For the first time, results from a study conducted by ARS researchers at Newark, Delaware demonstrated that this introduced biocontrol agent is established in southern Michigan and that its populations are increasing and expanding, and play a critical role in suppressing emerald ash borer populations in Michigan.


Review Publications
Yang, S., Duan, J.J., Lundgren, J., Van Driesche, R. 2012. Multiparasitism by Tetrastichus planipennisi (Hymenoptera: Eulophidae) and Spathius agrili (Hymenoptera:Braconidae): Implication for biological control of the Emerald Ash Borer (Coleoptera: Buprestidae). Biological Control. 65:118-123.

Duan, J.J., Taylor, P.B., Fuester, R.W., Kula, R.R., Marsh, P.M. 2013. Hymenopteran Parasitoids Attacking the Invasive Emerald Ash Borer (Coleoptera: Buprestidae) in Western and Central Pennsylvania. Florida Entomologist. 96:166-172.

Duan, J.J., Bauer, L., Abell, K., Lelito, J., Van Driesche, R. 2013. Establishment and abundance of Tetrastichus planipennisi (Hymenoptera: Eulophidae) in Michigan: potential for success in classical biocontrol of the invasive emerald ash borer (Coleoptera: Buprestidae). Journal of Economic Entomology. 106:1145-1154.

Last Modified: 4/17/2014
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