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    Effect of cold storage on the performance of Telenomus busseolae Gahan (Hymenoptera:Scelionidae), an egg parasitoid of Sesamia nonagrioides (Lefebvre) (Lepidoptera:Noctuidae)
    (Academic Press Inc Elsevier Science, 2005) Bayram, A; Ozcan, H; Kornosor, S
    Cold storage of both pupae and adults of Telenomus busseolae Gahan (Hymenoptera: Scelionidae) was investigated. Firstly, the effect of storage at three temperatures (4, 8, 12 +/- 1 degrees C), for seven time durations (1, 2, 4, 6, 8, 10, and 12 weeks) and four preimaginal ages of T busseolae pupae (9, 11, 13, and 15 day old parasitized eggs) in the eggs of Sesamia nonagrioides (Lefebvre) (Lepidoptera: Noctuidae) was studied. Laboratory performance of emerged parasitoids was measured and compared to that of the unstored (control) parasitoids. Storage had a significant adverse effect on mean adult emergence. T busseolae could be stored for 4 weeks at 4 and 8 +/- 1 degrees C but only 2 weeks storage was possible at 12 +/- 1 degrees C. Furthermore, mean percentage parasitism of host eggs by emerged parasitoids was reduced and F1 progeny sex ratio of the parasitoid became more male biased with increasing length of storage treatment. There was no effect of cold storage on the mean adult emergence of F1 progeny. Secondly, storage of adult T busseolae was investigated at two temperatures (8 and 12 +/- 1 degrees C) and six different storage times (1, 2, 4, 8, 12, and 16 weeks). Percent survival was reduced with longer storage times. Even though parasitoids survived for 12 weeks at both 8 and 12 degrees C temperatures, storage times influenced percent parasitism. Parasitoids stored for 8 weeks or longer parasitized fewer eggs than parasitoids stored for shorter times. Neither percent emergence nor sex ratio of F1 progeny was affected by storage temperatures and storage times. The current study suggests that T busseolae adults were successfully stored up to 12 weeks although some reduction in percent parasitism occurred at both temperatures. The ideal storage temperature for T busseolae adults was 12 +/- 1 degrees C. Results are discussed in relation to potential mass production and release of T busseolae for biological control of S. nonagrioides. (c) 2005 Elsevier Inc. All rights reserved.
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    Egg and larval parasitoids of the beet armyworm Spodoptera exigua on maize in Turkey
    (Springer, 2004) Sertkaya, E; Bayram, A; Kornosor, S
    The present study was conducted to determine egg and larval parasitoids of the beet armyworm Spodoptera exigua Hubner (Lepidoptera: Noctuidae), which is an important but sporadic pest in Turkey. High beet armyworm population levels were recently observed in fields of first and second crop maize in the southeast Mediterranean region of Turkey. The parasitoid species complex and its impact on the pest were analyzed in a 4-year study in first and second crop maize. The braconid larval parasitoids Microplitis rufiventris Kokujev, M. tuberculifer Wesmael, Meteorus ictericus Nees, Chelonus obscuratus (Herrich Schaffer) (an egg-larval parasitoid), Apanteles ruficrus (Haliday); the ichneumonid larval parasitoids Hyposoter didyniator (Thunberg) and Sinophorus xanthostomus Gravenhorst; and the egg parasitoid Trichogramma evanescens (Westwood) were found to be the natural enemies attacking the pest. Among the parasitoid species the solitary endoparasitoid H. didymator was the most prevalent species, being reared from 40.5% of the parasitized larvae found. Higher parasitism rates were recorded on first crop than on second crop maize in every year. Possible reasons for this difference in larval parasitism between two growing seasons include lower population of the pest and reduced insecticide applications in first crop maize fields which permitted higher parasitism. However, parasitoid activity was insufficient to counterbalance the population growth of the pest on subsequent second crop maize.
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    Sex allocation in Telenomus busseolae, a solitary parasitoid of concealed eggs
    (Blackwell Publishing Ltd, 2004) Bayram, A; Salerno, G; Conti, E; Wajnberg, E; Bin, F; Kornosor, S
    Telenomus busseolae Gahan (Hymenoptera: Scelionidae) is an important egg parasitoid of noctuid stem borers of gramineous crops, attacking egg masses of Sesamia spp. Under natural conditions, and whatever the host species attacked, these egg masses are generally concealed under the leaf sheaths or other narrow spaces, and vary greatly in size. In the work presented here, the influence of host patch size (4, 8, 16, 32, 64, or 128 eggs per mass) on the sex ratio and sex sequence pattern of ovipositing T. busseolae was investigated in the laboratory using Sesamia nonagrioides (Lefebvre) (Lepidoptera: Noctuidae) as host. The results are similar to those described for other parasitoids of aggregated hosts, and are in accordance with the Local Mate Competition model. With increasing egg mass size, the overall sex ratio (proportion of males) decreased, although additional males were laid at the end of the sequence in the larger masses (64 and 128 eggs). Sex sequence pattern always followed a males-first strategy, i.e., with a higher proportion of males at the beginning, but the whole sex ratio sequence was influenced by the size of the egg mass. Such results in a parasitoid of concealed eggs are compared to those observed in parasitoids of exposed eggs and discussed in terms of parasitoid reproductive strategies and evolutionary adaptations.