The cold storage effect on biological characteristics of Trichogramma brassicae Bezd
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عنوان دوره: سومین کنگره بین المللی حشره شناسی ایران
نویسندگان
Biological Control Research Dept., Iranian Research Institute of Plant Protection, AREEO, Tehran, Iran,
چکیده
A study was carried out to obtain the optimum temperature, stage and storage time of Trichogramma brassicae Bezd. (Hym.: Trichogrammatidae). Two pupal stages of the parasitoid viz. white-eyed (WP) and red-eyed (RP) as parasitized eggs of Sitotroga cerealella (Olivier) were stored at 4, 8 and 12 °C (all at 70 ± 5% RH and 16:8 h L:D). Thereafter, based on weekly interval, about 150 parasitized eggs of each treatment were randomly selected and transferred to growth chamber at 25 ± 1 °C, 70 ± 5% RH and 16:8 h L:D. Upon adult eclosion in each treatment, male and female adults were confined in glass tubes (10 × 2 cm) in pair and exposed to ~100 S. cerealella eggs daily until the death of parasitoids. The parasitized eggs were kept at above mentioned condition till progeny emergence. Longevity of adults, daily fecundity and sex ratio of progeny were recorded, separately. Data was analyzed based on life table method. The values of net reproductive rate (R0), intrinsic rate of increase (r) and finite rate of increase (λ) were estimated to be 31.33 offspring, 0.2800 day-1, and 1.3100 day-1, respectively, for 5 weeks storage at 4°C and in the white-eyed pupal stage. The values of the mentioned parameters were obtained as 3.30 offspring, 1.0700 day-1 and 1.0800 day-1 for 14 weeks storage at the same temperature and pupal stage. It is concluded that the optimum temperature and storage stage for the T. brassicae would be 4 ºC and the white-eyed pupal stage for 5 weeks.
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