Effect of early oviposition experience on host acceptance in Trichogramma (Hymenoptera: Trichogrammatidae) and application of F₁ sterility and T. principium to suppress the potato tuber moth (Lepidoptera: Gelechiidae)

Abstract

Laboratory experiments with Trichogramma principium Sugonyaev and Sorokina females offered potato tuber moth Phthorimaea operculella (Zeller) eggs demonstrated that wasps’ rates of oviposition were highest the first day and decreased gradually thereafter. In addition, when T. principium females were sequentially offered eggs from 250 Gy irradiated parents or obtained from non-irradiated moths, the probability of host acceptance was not influenced by treatment of host eggs. In a concurrent laboratory study, a large cage test with combinant releases of T. principium and 250 Gy irradiated moths produced the greatest reduction in potato tuber moth F₃-emerged progeny. Reductions obtained with irradiated moths alone, single release of irradiated moths with T. principium, and one or three releases of parasitoids were significantly higher than those in the control. From a pest management perspective, T. principium releases would synergistically complement the effects of F₁ sterility against potato tuber moth infestation.

Keywords:

• Phthorimaea operculella
• Trichogramma
• F₁ sterility
• pest management
• nuclear techniques
• gamma radiation

Acknowledgements

I thank Dr. I. Othman (General Director) and Dr N. Sharabi for their help and support. Technical and financial assistances were provided, in part, by contract no. 10781 of the International Atomic Energy Agency, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria.