Optimization of Methods for Mass-Rearing Newly Introduced Parasitoids for Biocontrol of Emerald Ash Borer
Beneficial Insects Introduction Research
2012 Annual Report
1a.Objectives (from AD-416):
1) Determine the effect of host larval stage, density and host to parasitoid ratio on host attack rate and critical fitness parameters of EAB larval parasitoids (Tetrastichus planipennisi and Spathius sp).
2) Determine the optimal temperature and photoperiod for the mass rearing of long-lived parasitoids capable of sustained (survival) high host-attack rates (parasitism).
3) Develop and ring-test Standard Operating Procedures (SOP) for mass rearing high quality EAB parasitoids.
1b.Approach (from AD-416):
We will use the tropical ash-based method to rear EAB larvae for tests with two different species of EAB larval parasitoids: T. planipennisi (a gregarious endoparasitoids) and Spathius sp (a newly imported gregarious, ectoparasitoid). Freshly cut tropical ash logs will be infested with fertilized EAB eggs laid on strips of un-bleached coffee filter paper. EAB egg-infested logs will be then placed into ventilated plastic boxes, and incubated under normal rearing conditions (27oC; RH 45 - 65%, and photoperiod L:D=16:8 hrs) prior to use in different tests for Objectives 1 and 2. A standardized size of the tropical ash logs (2.5 cm in diameter x 20 cm in length) will be used to rear EAB larvae for different tests.
Approximately 350 cuttings of the alternative host plant materials (Fraxinus udhei) were started between October and December of 2011. However, it would take approximately eight to 10 months for those plant cuttings to reach suitable sizes (1. 5 – 2. 5 cm in diameters) for use in various experiments planned in objectives 1 and 2 of the project. Because of the longer-than expected time producing host plant materials (live logs of Fraxinus udhei) for the study, the conduct of experiments with the emerald ash borer larvae and their parasitoids (Spathius galinae or Tetrastichus planipennisi) had to be delayed.