نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشگاه آزاد اسلامی واحد شیراز
2 گروه حشره شناسی، واحد شیراز، دانشگاه آزاد اسلامی، شیراز، ایران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Nasonovia ribisnigri is one of the important pests of lettuce. Hippodamia variegata with worldwide distribution, feed exclusively on it in Iran. The development, reproduction and life table parameters of H. variegata were studied at three constant temperatures (20, 25 and 30 ± 1°C). 100 eggs of ladybeetle were selected and maintained individually in Petri dishes. Newly emerged larvae were transferred to individual dishes, then development and mortality were assessed. After the emergence of adults, males and females were paired and transferred to new dishes. They were checked daily to record survival and fecundity until death. The data showed that the duration of total pre-adult stage of ladybeetle was found to decrease with increasing temperature from 22.38 days at 20°C to 12.62 days at 30°C. The oviposition period lasted 61.81, 50.06and 35.41days, with females laying an average of 1102.02, 1253.61 and 587.86 eggs at these three temperatures, respectively. The lowest mortality rate was observed 14% at 25°CThe highest intrinsic rate of increase (rm), finite rate of increase (λ) and net reproductive rate (R0) was recorded 0.2413, 1.239 (d–1) and 819.03 (offspring) at 25°C, respectively. But there were no significant differences in these parameters at 25 and 30 ± 1°C. Also, the shortest mean generation time (T) 25.44 (day) was observed at 30°C. According to these results, it seems that the 25-30 ±1°C were the optimum temperature for biological activities of H. variegata and this species has greater efficiency in biological control of lettuce aphid in these temperatures.
کلیدواژهها [English]
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