Biocontrol Science and Technology (2008) 18, 903-912

Nasser Said Mandour, Mahmoud Farag Mahmoud, Mohamed Abdel-Naiem Osman and Baoli Qiu (2008)
Efficiency, intrinsic competition and interspecific host discrimination of Copidosoma desantisi and Trichogramma evanescens, two parasitoids of Phthorimaea operculella
Biocontrol Science and Technology 18 (9), 903-912
Abstract: Trichogramma evanescens West. (Hymenoptera: Trichogrammatidae) and Copidosoma desantisi Annecke and Mynhardt (Hymenoptera: Encyrtidae) are potential parasitoids of the potato tuber moth (PTM), Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) in Egypt. Discrimination of a parasitized host from an unparasitized host would prevent wasting of time, eggs and reduce competition with conspecifics or heterospecifics. Therefore, we evaluated interspecific host discrimination, multiparasitism and intrinsic competition between the two wasp species. In a choice test, females of T. evanescens showed high interspecific host discrimination only when they were offered 2-day-old C. desantisi parasitized and unparasitized PTM eggs. In contrast, C. desantisi showed high host discrimination and preferred unparasitized eggs to PTM eggs harboring 2-h- or 2-day-old T. evanescens ' eggs. We also evaluated the effect of different introduction sequences on the efficacy of the two wasps. Dissection data indicated that the two parasitoids had a negative impact on each other. There was a significant reduction in the total number of deposited eggs as well as total number of parasitized hosts by each parasitoid. Regarding the rearing experiment, the total number of T. evanescens-induced black eggs or C. desantisi formed mummies in combined treatments was significantly lower than in single parasitoid treatments (control). Moreover, C. desantisi was inferior and did not develop from any multiparasitized host regardless of oviposition order. It was suggested that combined release of the two wasps would not elevate rate of parasitism over that of single parasitoid treatments and competition between them would reduce their efficacy.
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Link to article at publishers website
Database assignments for author(s): Mandour Nasser, Mahmoud Farag Mahmoud, Mohamed A.M. Osman, Bao-Li Qiu

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution
environment/habitat manipulation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Phthorimaea operculella		Egypt
Trichogramma evanescens (parasitoid)	Phthorimaea operculella		Egypt
Copidosoma desantisi (parasitoid)	Phthorimaea operculella		Egypt