LIFE TABLE ANALYSIS TO MEASURE THE IMPACT OF PARASITOIDS ON EMERALD ASH BORERS IN THE US
Beneficial Insects Introduction Research
2012 Annual Report
1a.Objectives (from AD-416):
The purpose of this agreement is to quantify the impact of introduced parasitoids on the survival of emerald ash borer (EAB), Agrilus planipennis Fairmaire, populations. The work will be done in the US, using one species of American ash (Fraxinus pennsylvanica). Evaluations will be based on life tables developed from marked cohorts of eggs and larvae at six field sites in natural forests where the parasitoids imported to the US to control EAB either have already been released or will be released in the first year of the study. Specific objectives will be:
1. Locate 3 control and 3 treatment sites. At the treatment sites, release the three EAB parasitoids imported from China (Oobius agrili, Tetrastichus planipennisi , Spathius agrili).
2. At all sites, assess the impact of parasitoids on cohorts of EAB eggs and larvae/pupae in green ash (F. pennsylvanica)
3. Use data from EAB cohort studies to develop life tables for EAB populations and compare stage specific survival rates and other life table parameters.
1b.Approach (from AD-416):
We will test whether parasitoids introduced from China will greatly reduce survival of emerald ash borer cohorts on green ash trees (F. pennsylvanica) in U.S. Work will be done in Michigan at three control and three treatment sites, the latter where three introduced EAB parasitoids either have been or will be released. Cohorts of EAB eggs and larvae/pupae will be created at each site, and used for construction of site-specific life tables for measuring the impact of released parasitoids.
Additional (~500) cohorts of EAB eggs and larvae established in the summer of 2010 at three different study sites in Michigan were sampled in the fall of 2011 and Spring 2012. Preliminary data analysis showed that both North American native and introduced parasitoids appeared to have begun reducing the density of the emerald ash borer in Michigan. However, final life-table analysis will be conducted this fall (FY 2013) to determine the effect of introduced parasitoids on EAB population dynamics.