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1.
The development, longevity, fecundity and sex ratio of the predatory miteAmblyseius longispinosus (Evans) were studied at different constant and alternating temperatures withTetranychus cinnabarinus as prey. Alternating temperatures had no significant effect on the developmental times, in comparison with optimal constant temperature. At the alternating temperature of 33/23°C the mean duration of the life cycle from egg to adult was obvious longer with 5.0 and 4.4 days forA. longispinosus females and males than at alternating temperature of 30/20°C with 4.2 and 4.1 days for females and males. At 25°C constantly the egg stage was the longest during development and required a mean of 2.2 days.A. longispinosus females and males remained in larval stage for 0.5 and 0.6 days. The protonymphal and deutonymphal stage lasted for 0.7 and 1.1 for females and for 0.7 days for males, respectively. At all temperatures the development of females required significantly longer than of males. Longevity ofA. longispinosus adults was variable to tested temperatures: At 25°C females lived for 33.1 days, at 30/20°C for 30.6 days and at 33/23°C for 29.9 days. At 25°CA. longispinosus females produced a mean total progeny of 48.8 eggs and the mean duration of oviposition period was 21 days; at 30/20°C and at 33/23°C a mean number of 49.1 and 48.2 eggs was laid during an oviposition period of 20 days. Temperature had no effect on the sex ratio of predatory mites, about 70% of mites became females at all temperatures.  相似文献   

2.
Bactimos was incubated for 30 days under 7 constant temperatures (i. e. ?20, ?10, 5, 25, 35, 40 and 45°C). The insecticidal activity of the compound was evaluated against 2nd and 4th instar larvae ofCulex pipiens molestus after 1, 3, 7, 10, 15 and 30 days of storage. No loss in the insecticidal activity of the Bactimos was detected after 30 days at ?20, ?10 and 5°C. At temperatures above 25°C the insecticidal activity reduced as the storage period increased. The LT50 value of Bactimos for the 2nd and 4th instar larvae at 24 h and 48 h exposure was found to decrease as the temperature increased.  相似文献   

3.
对喜马拉雅长叶松种子进行24小时GA3和H2O2浸泡预处理和15d的2-3℃低温预处理后,研究了在20℃,25℃和30℃萌发条件下,21个不同种源的喜马拉雅长叶松种子的萌发情况。结果表明,H2O2（1%v/v）和GA3（10mg/L）浸泡预处理,种子萌发率分别是82.39%和78.19%,而未经预处理的种子平均萌发率为70.79%。GA3和H2O2浸泡预处理分别使种子萌发时间缩短了8d和10d。在超过21天的20℃萌发条件下,湿冷处理提高了种子萌发率和缩短了萌发时间 而在25℃和30℃萌发条件下,总的萌发率未受到影响。喜马拉雅长叶松种子因缺少休眠而表现出很好的萌发,但是因为越来越多的造林项目需要大量的种子,播种预处理有利于提高种子萌发率和萌发速率,有助于满足种子需求。  相似文献   

4.
Studies on the biology of the predaceous mite Cunaxa capreolus Berl. (Acari, Prostigmata, Cunaxidae) During life cycleCunaxa capreolus Berlese passes through egg, larva, three nymphal stages and adult. Each moving stage is proceeded by a quiescent one. Biological process such as hatching, moulting and mating were investigated. Female usually deposites its eggs singly in protected places. Number of deposited eggs per female, when fed on book lice (Psocoptera), was positively correlated with temperature. It averaged 24.6, 30.7, 40.7, and 43.5 eggs at 15°, 20°, 25° and 30 °C. Incubation period as well as duration of immature stages and adult longevity were negatively effected with temperature. The generation period (from egg to egg) ranged from 24.8 to 64.2 days when temperature changed from 30° to 15 °C. Within these limits of temperature, the simple regression indicated that an increase of 1 °C decreased the generation period for about 2.6 days.  相似文献   

5.
The striped stem borer, Chilo suppressalis (Walker), is one of the most economically important rice pests worldwide. However, biological control of this pest using natural enemies has rarely been documented. Indigenous natural populations of four Trichogramma species (i.e., T. japonicum, T. chilonis, T. dendrolimi, and T. ostriniae) were collected from the eggs of C. suppressalis in paddy fields. With the objective of screening suitable candidate species for controlling the striped stem borer, parasitism by these four Trichogramma species of the eggs of their native host, C. suppressalis, was evaluated at five temperatures (18, 22, 26, 30, and 34?°C) and four relative humidity (RH) regimes (30, 50, 70, and 90?%). The temperature and the humidity significantly affected the ability of all of the Trichogramma species to parasitize the eggs of their host. T. chilonis parasitized more eggs at 26?°C than at the other temperatures. By contrast, T. dendrolimi, T. ostriniae, and T. japonicum performed best within a wider temperature range. The host number parasitized was highest at 70?% RH and differed significantly among the Trichogramma species at all of the temperatures and humidities tested, except at 30?°C and 50?% RH. Generally, T. dendrolimi and T. japonicum performed better than the other species at 18–26 and 30–34?°C, respectively, whereas T. ostriniae parasitized the fewest host eggs at 30–70?% RH. Both T. dendrolimi and T. japonicum appear to be promising candidates for augmentative release against C. suppressalis in northeastern China.  相似文献   

6.
Toxicity of dichlorvos, permethrin, and carbaryl to the flesh fly,Parasarcophaga argyrostoma R.-D. was determined at 3 post-treatment temperatures, 15°C, 25°C, and 35°C. Toxicity of dichlorvos and carbaryl to both males and females was significantly greater (P<0.05) at 35°C than at 15°C. However, differences in LD50 values between males and females were not significant (P<0.05). Dichlorvos and carbaryl were respectively 3.75 of 2.03 times more toxic to males and 3.14 and 1.91 times more toxic to females at 35°C than at 15°C. Permethrin was significantly (P<.05) more toxic to both males and females at 15°C than at 35°C. Permethrin was respectively 2.50 of 2.18 more toxic at 15°C than at 35°C to males and femalesP. argyrostoma.  相似文献   

7.
The eggs ofArgas (Argas) reflexus (Fab.) were exposed to 0.05% colchicine on 9th, 15th or 23rd–25th days of embryonic development at 25°C and 30% RH. The eggs on the 15th and 23rd–25th days of development were the most sensitive to colchicine. In these experiments 6.9% and 9.4% embryos died, respectively. The largest number of disturbances of egg hatch (11.5%) were observed after exposure of the eggs to colchicine on 23rd–25th days of embryogenesis.  相似文献   

8.
Pear lace bug, Stephanitis pyri (F.) (Heteroptera: Tingidae) is a pest of apple and pear trees and ornamental Rosaceae plants in Mediterranean countries and palearctic region. The aim of this study is to determine the effects of temperatures on S. pyri in the laboratory. Development and fecundity of S. pyri reared on apple leaves (Pyrus malus L.) were investigated at five constant temperatures (20, 23, 26, 29 and 32 ± 1°C) and a 16L:8D photoperiod. Longevity was determined to be 12.6 days at 32°C and 58.7 days at 20°C for females, and 9.7 and 37.7 days for males. Females laid 186.9 eggs per female with the highest number achieved during 28.5 days of oviposition period at 26°C. Female lifetime fecundity was reduced at 32°C (40.0 eggs per female). While the net reproductive rate (R 0) was highest at 26°C, the intrinsic rate of natural increase (r m ) was highest at both 26 and 32°C. The mean generation time (G) was estimated to be 27.2–78.4 days at 20 and 32°C, respectively. The longest development times for egg and total nymph stages were obtained as 22.0 and 24.9 days, respectively, at 20°C. S. pyri developed fastest from egg to egg in 24.3 days at 32°C. The lower developmental threshold (T 0) was 9.7°C and the thermal constant (K) was 517.3 degree-days for S. pyri. Thus, S. pyri is calculated to have 3.8 theoretical generations in Tekirdag. The optimum developmental temperature for S. pyri was 26°C.  相似文献   

9.
To investigate the reproductive traits and diel activity ofMonochamus saltuarius, 14 pairs of the adults were reared and observed at each of 20°C and 25°C. Both sexes were more active at 25°C than at 20°C irrespective of the presence or absence of light. A diel change in behavior during 24 h was found on 33% of a total of 48 observations of three age classes of both sexes. No significant difference was found in the mean longevity between sexes or between the two temperature conditions. The time required for reproductive maturation showed no significant difference within the same sex when reared at 20°C and 25°C. The mean oviposition period was significantly longer at 25°C (28.8 days) than at 20°C (12.2 days). The mean lifetime fecundity was significantly greater at 25°C than at 20°C. There was no significant difference in the oviposition ratio (number of eggs deposited/number of oviposition wounds excavated), oviposition rate or hatchability for females between the two temperature conditions.  相似文献   

10.
Acyrthosiphon gossypii is a widespread, major pest of cotton in central Asia. Effects of specific temperatures on A. gossypii development and survival are unknown and would be useful in helping interpret population dynamics and devising management tactics for this pest. In this paper, the effect of temperature on the life table of A. gossypii reared on cotton was evaluated under laboratory conditions using temperatures of 18, 21, 24, 27, and 30 °C. The developmental rate of immatures increased exponentially from 18 to an optimum around 27 °C and then declined. The estimated lower developmental threshold was 8.0 °C, and 107.5 degree days were required for development from the first instar to adult. The percentage survival of immature stages varied from 81 to 91 % within the range of 18-27 °C. Survival declined to 27 % at 30 °C. The average longevity of adult females was 15.7, 11.7, 8.2, 5.2, and 2.8 days, and the average number of offspring produced per female was 46, 38, 20, 14, and 0, at temperatures of 18, 21, 24, 27, and 30 °C, respectively. From 21-27 °C, the intrinsic rate of increase of A. gossypii was significantly higher than at 18 °C, indicating that 21–27 °C was within the optimal range for the growth of A. gossypii, and that 30 °C constant is beyond the upper limit for reproduction. The observations will form the basis of a forecasting system and could account for the decline of the species on cotton in central Asia as well as other regions during hot summer months.  相似文献   

11.
Trichogramma spp. are major parasitoids of lepidopteran pest eggs, but there is large variation in efficacy toward a given pest among the numerous described Trichogramma species. It is important to select the Trichogramma species that most effectively parasitize and develop in target pest eggs for biological control. In this context, Trichogramma pretiosum, T. exiguum, T. atopovirilia and T. acacioi were studied in Heliothis virescens eggs under different thermal conditions. The parasitoids were reared at constant temperatures of 20, 25 and 30°C and tested at these respective temperatures, while parasitoids reared at 25°C were also tested at 20 and 30°C, for a total of 20 species–temperature combinations. About 30 H. virescens eggs were offered to the parasitoids for 24 h. Among the four species, parasitism rate by T. atopovirilia was highest at all temperature conditions, whereas T. acacioi had the lowest rates of parasitism at 25°C and 25/30°C. Parasitism ranged from 13.8 to 43.8% among all species–temperature combinations. Viability (emerged parasitoids) ranged from 80.8 to 98.4%, and was deemed satisfactory. The emergence rates of T. exiguum and T. acacioi were affected by temperature. Temperature also affected the sex ratio of T. exiguum at 25/30°C, whereas T. pretiosum and T. acacioi produced females predominantly independent of temperature. Overall, the parasitoid T. atopovirilia was the most efficient in parasitizing H. virescens eggs, though the levels of parasitism obtained might not ensure its successful use in biological control programs. The temperature-related differences in biological traits observed in the four Trichogramma species tested hint at the importance of making careful choices regarding climatic conditions where the parasitoid is going to be used when selecting a species for biological control programs.  相似文献   

12.
The mortality of adults, eggs, larvae and pupae of the cowpea storage bruchid,Callosobruchus maculatus (Fab.) was observed in four different high carbon dioxide (CO2) in air atmospheres (88% CO2, 70% CO2, 60% CO2 and 50% CO2) at 25°C and 32°C respectively, and 70% RH. All the developmental stages ofC. maculatus were completely killed within 5 days in the 88% CO2 in air atmosphere and within 12 days in the other high CO2 atmospheres tested. The adult and egg stages were most susceptible, and the old larvae and pupae, the least susceptible to the high CO2 atmospheres. Mortality ofC. maculatus was significantly influenced by the level of CO2, stage of insect development, exposure period and temperature.  相似文献   

13.
The development of the red palm weevil, Rhynchophorus ferrugineus (Olivier) was investigated on a newly developed semiartificial diet as compared with two natural diets namely sugarcane stem and banana fruit. The weevil was successfully maintained on these diets and duration of the life cycle for males and females, respectively were 164.97 and 194.61 days on the semiartificial diet, 192.5 and 186.5 days on banana, and 172.00 and 170.00 days on sugarcane. The average egg production per female was shown to be significantly higher on the semiartificial diet, being 184.00?±?18.68 eggs compared with an average of 125.00?±?11.97 and 133.00?±?15.21 eggs on banana and sugarcane, respectively. The fertility ranged between 94?–?100?% in those eggs deposited by females previously reared on the tested diets. The developed semiartificial diet was shown to be suitable for maintaining laboratory colonies of the red palm weevil, and it can substitute natural diets.  相似文献   

14.
Seeds of Albizia chinensis(Osb.) Merr. in addition to water were also treated with different treatments by incubating in ethyl alcohol, acetone, and petroleum ether at room temperature for different du...  相似文献   

15.
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16.
Pagiocerus frontalis produced offspring on maize between 13°C and 30°C. Below and above these temperatures development was not completed. The optimum developmental temperature was 25°C.P. frontalis was able to produce F1 between 20% and 75% r.h. though the mortality at lower rel. humidities was high.  相似文献   

17.
Abies lasiocarpa (Hook.) Nutt. seeds germinated and the seedlings grew on under controlled environments (18 h photoperiod and 16/8 h thermoperiods; 10/10oC, 20/20°C, 20/10°C, and 25/10°C). The experiment was concluded after 180 days, and the seedlings were scored for stem diameter and length. Four provenances were included: Colorado “high elevation”; (CO), Oregon 1 600 m a.s.l. (OR), British Columbia 1200 m a.s.l. (BC), and Finland (BCF; originally from British Columbia 1800 m a.s.l.). A cold‐moist pretreatment for 30 days improved germination and seedling growth in the BC and BCF seed lots, while the CO and OR seed lots were less affected. Daily fluctuating temperatures improved germination in the BC and BCF seed lots, the widest fluctuation 25/10°C producing the greatest germination. The average length of the seedlings was 34 mm at 20/20°C, 33 mm at 20/10°C, and 37 mm at 25/10°C; differences in hypocotyl length being most important. There were small but significant differences between the provenances in their reaction to temperature regime. The major part of the seedlings produced 2 or 3 flushes of growth in the 180 days period, the CO provenance having the most stabile buds and the OR provenance being the most labile.  相似文献   

18.
The effects of seed moisture content (MC), gibberellic acid (GA3) concentration, chilling and priming pretreatments on the germination of common alder (Alnus glutinosa) and downey birch (Betula pubescens) seeds were examined. After treatment, the seeds were allowed to germinate for 42 days at 15 °C or 20 °C (dark)/30 °C (light). Treatment responses were similar at both temperatures and in both species. GA3 treatment of seeds in fully imbibed (FI) state for 30 days, or at the lower, target moisture content (TMC) for 30–90 days, significantly improved germination, but longer treatment periods reduced it (FI seeds) or had no effect (TMC seeds). Priming for two days improved germination in the FI seeds, but more than 4 days reduced it. Priming for up to 14 days had little effect on the germination of the TMC seeds.  相似文献   

19.
The predatory mite Typhlodromus pyri Scheuten (Acari, Phytoseiidae) has been reported as an important predator of the European red mite, Panonychus ulmi (Koch) (Acari, Tetranychidae) in apple culture and vineyards at below 25?°C. However, sufficient biological data was lacking on its efficiency at temperatures above 25?°C. Therefore, the purpose of the present laboratory work was to obtain experimental data on prey consumption during development as well as longevity and reproduction of T. pyri on apple leaf discs and in Plexiglas cells at constant temperatures of 25?±?2?°C and 30?±?2?°C with P. ulmi as prey.  相似文献   

20.
Temperature effects on developmental period, survival rate, and reproductive capacity of Aphis rumicis L. were studied on Broadleaf dock and Swiss chard at four constant temperatures (17.5°C, 20°C, 22.5°C, and 25°C). The developmental time of immature stages ranged from 10.9 days at 17.5°C to 6.5 days at 25°C on Broadleaf dock, and 11.8 days at 17.5°C to 6.5 days at 25°C on Swiss chard. The total percentage of survivorship of immature stages varied from 54.2% and 67.6% 17.5°C–25°C on Broadleaf dock, and 49.7% and 62.4% at 17.5°C–25°C on Swiss chard. The largest r m value occurred with 0.2845 at 25°C on Broadleaf dock and with 0.2785 at 25°C on Swiss chard. The results obtained on this study indicated that Swiss chard was a less favorable host of the A. rumicis than Broadleaf dock. The optimal temperature for A. rumicis growth, developmental time, and reproduction was 22.5°C–25°C.  相似文献   

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