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Age-specific life table parameters, survivorship, and extra molting of the beet armyworm, Spodoptera exigua (Hübner), were determined at eight constant temperatures of 12, 15, 20, 25, 30, 33, 34, and 36°C with a variation of 0.5°C on sugar beet leaves. No development was observed at 12 and 36°C. The survivorship of overall immature stages was higher at 25°C than the other temperatures. The highest (0.276 d(-1)) and lowest (0.149 d(-1)) value of the intrinsic rate of increase (r) was observed at 30 and 20°C, respectively. Although the highest value of the net reproductive rate was at 25°C (377.7 female offspring at 25°C and 127.4 female offspring at 30°C), the highest value of r was at 30°C, which indicated the importance of shorter development time (16.9 d at 30°C and 27.2 d at 25°C) in enhancing r. The relationship between temperature and r was modeled using the Lactin-2 model. The lower temperature threshold, the upper temperature threshold, and optimal temperature for the r were estimated at 13.1, 32.2, and 34.1°C, respectively. The mean generation time decreased significantly with increasing temperature, with the longest (35.9 d) and shortest (15.1 d) mean generation time was calculated at 20 and 33°C, respectively.

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Effects of Beauveria bassiana on Andrallus spinidens Fabricius (Hemiptera: Pentatomidae), a predator of lepidopterous larvae in rice fields were investigated. The experiments were conducted at a concentration of 3×10 5 conidia ml -1 (LC 30 ) of B. bassiana on life table and some biochemical parameters of fifth instar nymphs. Insects were infected by dipping in the conidial suspension for 10s. The results showed that pre-oviposition period, fecundity, percent egg hatchability and longevity of treated bugs were not significantly affected compared with the control. Esterase (using β-naphtil as substerate) and glutathione S-transferase activity in A. spinidens increased 48 h after treatment. The fungus did not cause adverse effect on acetylcholinesterase activity. B. bassiana did not cause significant difference on life table parameters of A. spinidens compared to the control. According to the present study, it can be concluded that B. bassiana is compatible with the predatory bug at sublethal concentration (LC 30 ).

Life table studies are essential tools for understanding population dynamics. The life table parameters of Aphis gossypii Glover (Hemiptera: Aphididae) feeding on the host plant, Hibiscus syriacus L. were studied under laboratory (25±1°C and relative humidity of 65±5% and a photoperiod of 16L : 8D h) and field conditions (23-43°C, and relative humidity of 27-95%). The data were analysed using the age-stage, two-sex life table theory. The life table studies were started with 50 and 40 nymphs in laboratory and field conditions, respectively. Under laboratory conditions, A. gossypii reared on H. syriacus had a higher survival rate, fecundity, and longevity than those reared under field conditions. When reared under field conditions, A. gossypii had a longer nymphal developmental time, shorter adult longevity, and lower fecundity than those reared under laboratory conditions. The intrinsic rate of increase (r), net reproductive rate (R 0 ), and the finite rate of increase (λ) under laboratory conditions, were higher than those obtained under field conditions. Nevertheless, there were no significant differences in the mean generation time T (days) between field and laboratory conditions. In the present study, the results clearly showed that life table parameters of A. gossypii were significantly different under field and laboratory conditions. These results could help us to understand the A. gossypii population dynamics under field conditions. The results could also help us make better management decisions for economically important crops.