جستجوی مقالات مرتبط با کلیدواژه "constant temperatures" در نشریات گروه "گیاهپزشکی"

The two-spotted spider mite Tetranychus urticaeKoch, the date palm dust miteOligonychus afrasiaticus(McGregor), and the citrus brown mite Eutetranychus orientalis(Klein) of family Tetranychidae are key pests of fruit trees, field crops, and ornamentals that cause significant yield losses. The purpose of this research wasto assess the effect of three constant temperatures (22, 27, and 32 °C) on the developmentaltime, life-table parameters, and consumption rate of the predatory beetle Stethorus gilvifrons (Mulsant) on maize leaf disks with T. urticae, O. afrasiaticus, and E. orientalisas food. The results indicated a significant difference between the three different temperatures and prey types. The shortest developmental time was recorded on T. urticae(9.30 and 10.10 days) at 32 °C, while the longest was on E. orientalis(23.34 and 22.50) at 22 °C for females and males, respectively. The shortest female longevity was on E. orientalis (21.14 days) at 32 °C, and the longest was 39.12 days on T. urticaeat 22 °C. The fecundity increased as temperature increased, from 114.6 eggs with a daily rate of 3.81 eggs per female/day at 22 °C to 235.0 eggs with a daily rate of 10.78 eggs per female/day at 32 °C on T. urticae.The highest net reproductive rate (R0), intrinsic rate of natural increase (rm), and finite rate of increase (λ) were recorded at 32 °C, whereas the lowest values were recorded at 22 °C when predatory beetles S. gilvifrons were fed on three prey diets. Gross reproduction rate (GRR) recorded the highest value (132.8 offspring/individual) when fed on T. urticae at 32 °C and the lowest value (55.30 offspring/ individual) when fed on E. orientalisat 22 °C. The highest consumption rate of adult males and females was 226.8 and 245.4 individuals when fed on O. afrasiaticusat 22 °C, while the lowest was 123.6 and 133.8 individuals on E. orientalisat 32 °C. Thus, the results obtained here revealed that temperature and prey diets influence the developmental rate and reproduction of S. gilvifrons. Additionally, T. urticaeis better for mass rearing of S. gilvifronsthan O. afrasiaticusand E. orientalisas food.

The foraging behavior of a natural enemy is greatly affected by temperature. The influence of different constant temperatures on the functional response and prey consumption of the mated female of Neoseiulus barkeri Hughes on nymphal stages of Tetranychus urticae Koch was evaluated. Four ambient temperatures (20، 25، 30 and 35 ± 1°C) and six prey densities (2، 4، 8، 16، 32 and 64 individuals) were used during a 24-h period in functional response experiments. The effect of seven constant temperatures (15، 20، 25، 27، 30، 35 and 37 ± 1°C) on prey consumption of N. barkeri on nymphal stages of T. urticae was also determined. Using the logistic regression، the type II functional response was determined for adult female of N. barkeri at all temperatures. The type II Rogers'' model was used to estimate the values of the searching efficiency (a) and handling time (Th). The value of the searching efficiency increased with increasing temperature from 20 to 30°C (0. 0364 to 0. 0731 h-1 respectively)، then decreased at 35°C (0. 0646 h-1). The handling time of this predator decreased when the temperature increased from 20 to 35°C، and the minimum value was observed at 35°C (0. 5548 h). Similarly، temperature had a significant effect on the prey consumption of adult females of N. barkeri over the range of 15-37ºC. The minimum and maximum daily prey consumption of whole immature stages of N. barkeri was observed at 15°C and 35°C respectively. The highest and the lowest number of total preys consumed by all immature stages of N. barkeri were 14. 61 and 8. 79 preys that occurred at 20°C and 15°C respectively. During the oviposition period، the total prey consumption increased with increasing temperature from 15 (160. 43 preys) to 30°C (286. 71 preys) and then declined and reached to 191. 57 preys at 37°C. The results of this study underscore the effect of temperature on searching efficiency and prey consumption of N. barkeri.