Life table, reproduction, and population growth parameters of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), were determined on nine soybean (Glycine max L.) cultivars ('032', '033', 'Hill', 'M4', 'M7', 'M9', 'M11', 'TMS', and 'Zane') at 25°C. The age-specific survival rate of eggs and immature stages was higher on 033 in comparison with other cultivars. The gross fecundity rate ranged from 911 on M9 to 1,296 on Zane, but the differences were not statistically significant. The net fecundity rate was significantly higher on 033 (1,082 eggs per female) than on other cultivars. The gross fertility rate significantly differed on tested cultivars, and was the highest on Zane (1,257 eggs per female) and lowest on Hill (813 eggs per female). The net fertility rate varied from 532 on M11 to 1,082 eggs per female on 033. Both daily number of eggs and daily number of fertile eggs laid per female varied significantly among the different cultivars, and were the highest on TMS (90 for both parameter) and lowest on M7 (47 and 43), respectively. The values of net reproductive rate, intrinsic rate of increase, and finite rate of increase were significantly higher on 033. The shortest generation time (23 d), shortest doubling time (1.66 d), and highest percentage of female offspring (56%) also were obtained on 033. According to population growth parameters, 033 and Hill partially were susceptible and resistant, respectively, to S. exigua. The results of this study provide direction to design a more comprehensive integrated pest management program for this pest.

The cabbage aphid, Brevicoryne brassicae (L.), is one of the major insect pests of cole crops in Iran. In most instances outbreaks are normally kept under control by application of insecticides. In this study, the sublethal effects (LC30) of three insecticides, acetamiprid, buprofezin, and thiamethoxam-lambda cyhalothrin, (TLC) were evaluated on the population growth rate of the progeny of insecticide-treated cabbage aphid adults. The age-stage, two-sex life table method was used to analyze the collected data. The results indicated that the insecticide applications affected the duration of the preadult period, their survival, reproduction, life span/longevity, and consequently, the population growth rate of the F1 generation. The indicators of the greatest sublethal effects were noted in the progeny of the TLC-treated adults. These included the lowest net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (λ), and the longest mean generation time (T). The highest values of r, λ, R, and the lowest value of T occurred in the control group followed by, in order, the acetamiprid and buprofezin groups. These research findings will be useful in the development and implementation of future aphid management programs.

No abstract

No abstract

No abstract