Title: INFLUENCE OF REARING HOST ON ADULT SIZE AND OVIPOSITIONAL BEHAVIOR OF MASS PRODUCED FEMALE TRICHOGRAMMA MINUTUM RILEY AND TRICHOGRAMMA PRETIOSUM RILEY(HYMENOPTERA: TRICHOGRAMMATIDAE)
Greenberg, Shoil - TX AGRI EXPER STATION
Wu, Zhixin - TX AGRI EXPER STATION
Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 1997
Publication Date: N/A
Interpretive Summary: Trichogramma spp., which are tiny parasitic wasps that attack the eggs of more than 400 pest species, are among the most widely used biological control agents in the world. The vast majority of the Trichogramma release for biological control programs are reared on factitious hosts. This in vivo rearing increases production costs and limits production capacity. The use of an artificial diet based in vitro rearing system would significantly reduce production costs and health hazards associated with Trichogramma rearing while permitting the use of automated rearing systems, which will significantly increase production capacity. Our findings show that Trichogramma females from larger hosts are larger and that larger females parasitized more artificial host eggs and deposited more eggs than did females from small hosts. These findings indicate the need to provide sufficient artificial diet and prevent overcrowding in an in vitro rearing system.
The size (body length) of Trichogramma pretiosum Riley and Trichogramma minutum Riley adult females is, to a great extent, dependent on the size of the host eggs on which they developed. The size of Trichogramma females is positively correlated with their fecundity. Two kinds of artificial eggs were used, wax artificial eggs (WAEs) and stretched plastic artificial eggs s(SPAEs), with oviposition stimulus to induce females reared on different hosts to oviposit. Trichogramma pretiosum reared on Helicoverpa zea (Boddie) and Manduca sexta (Linnaeus) eggs attacked 80.0 to 83.3% of WAEs compared to the 49.5% of eggs attacked when the parasitoid was reared on Sitotroga cerealella (Oliver) eggs. Trichogramma minutum reared on H. zea eggs, an artificial diet, or S. cerealella eggs oviposited in 76.2, 89.3 or 30.9%, respectively, of SPAEs.