Biological Potential Variability to Field-Temperature Conditions Of Nine Trichogramma strains

• Elisabeth Tabone(1) Céline Bardon(2), and Claude Alauzet(2)
• (1) INRA, 1382 Route de Biot, 06560 Valbonne, France.
• (2) UPS LADYBIO, 118 Route de Narbonne, 31062 Toulouse, France
• The Third International Conference onIPM Role in Integrated Crop management and Impacts on Environment and Agricultural Products. 26-29 November 2005, Giza, Egypt.

Abstract

In order to select the best parasitoid to control the diamondback moth Plutella xylostella Linnaeus (Lepidoptera: Plutellinae) in France, we studied, in laboratory, nine Trichogramma strains (Hymenoptera: Trichogrammatidae). Two studies permitted us to determine their adaptability to field-temperature conditions. The first study consisted to measure the fecundity, offspring percentage emergence and offspring sex ratio under three temperatures (15, 25 and 35°C). A female (24 h old, fed and mated) of each Trichogramma strain parasitized Ephestia kuehniella Zeller eggs (Lepidoptera: Pyralidae) in a glass tube during 48 h. Fecundity was maximal at 25°C. Trichogramma laid generally more eggs at 15°C than at 35°C. The second study measured the female survival after a thermal shock at 5°C during 6 h and at 40°C during 2 h. No mortality appeared after the shock at 5°C. The strains reacted differently after the shock at 40°C with 60% to 0% of survival according to the strain.