Based on former studies on weather simulator modules in IPMist laboratory, study on visual programming of stochastic weather generator(VS-WGEN)was continued. In this study, Markov Chain, Monte Carlo, Fourier Series, a...Based on former studies on weather simulator modules in IPMist laboratory, study on visual programming of stochastic weather generator(VS-WGEN)was continued. In this study, Markov Chain, Monte Carlo, Fourier Series, and weak stationary process were used to generate the daily weather data in software Matlab 6. 0, with the data input from 40 years' weather data recorded by Beijing Weather Station. The generated data includes daily maximum temperature, minimum temperature, precipitation and solar radiation. It has been verified that the weather data generated by the VS-WGEN were more accurate than that by the old WGEN, when twenty new model parameters were included. VS-WGEN has wide software applications, such as pest risk analysis, pest forecast and management. It can be implemented in hardware development as well, such as weather control in weather chamber and greenhouse for researches on ecological adaptation of crop varieties to a given location over time and space. Overall, VS-WGEN is a very useful tool for studies on theoretical and applied ecology.展开更多
Transgenic plants expressing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) were grown on over 22.4 million ha worldwide in 2004, nine years after their first commercial use in 1996. Insect resis...Transgenic plants expressing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) were grown on over 22.4 million ha worldwide in 2004, nine years after their first commercial use in 1996. Insect resistance management (IRM) is critical for the sustainable use of Bt plants. Theoretical models suggest that plants expressing two dissimilar Bt toxins in the same plant have the potential to delay insect resistance more effectively than single toxin plants used sequentially or in mosaics. Transgenic cotton plants expressing two Bt toxins are now registered for use in the US and Australia, and several companies are developing new varieties of Bt corn, Bt cotton and Bt brassicas with dual Bt genes for commercial use in the coming years. We conducted two greenhouse studies using a unique model system composed of broccoli plants transformed to express different Bt toxins (Cry1Ac, Cry1C or both) combined with populations of diamondback moth, Plutella xylostella, carrying resistance to each Bt toxin, with over 20 generations of selection in each study. The results from the first study indicated that resistance to two-gene plants was significantly delayed compared to single gene plants deployed sequentially or in mosaics. The second study proved that using two-gene plants alone is better for sustainable IRM than concurrent use of one-and two-gene plants in the same region. These results have important implications for the development, deployment and regulation of transgenic insecticidal plants.展开更多
Behavior and olfactory responses of grasshopper hatchlings, Melanoplus sanguinipes (F.), to odours from plant foliage and volatile compounds were tested using a glass Y-tube olfactometer and electroantennogram (EAG)te...Behavior and olfactory responses of grasshopper hatchlings, Melanoplus sanguinipes (F.), to odours from plant foliage and volatile compounds were tested using a glass Y-tube olfactometer and electroantennogram (EAG)techniques respectively. In single choice trials, newly hatched hoppers were much more sensitive to the odour from intact leaves and chopped foliage of ryegrass and wheat than other plants. Chopped sorghum leaves, but not stem-cut sorghum,were also significantly attractive. The orientation responses of grasshopper hatchlings to these plants were highly consistent with those of last instar hoppers and adults. When ryegrass was employed as the control, the odour from stem-cut alfalfa was more attractive. There was no significant difference in hopper orientation responses to the odours from chopped seedlings of sorghum, alfalfa, wheat or ryegrass.However, significantly more hoppers preferred the chopped ryegrass control to chopped Louisanna sage. Measurement of the EAG response of first instar hoppers to these plant odours showed that the odour of Louisanna sage elicited the greatest response amplitudes. In olfactory tests using different volatile components, Z-3-hexenol, E-3-hexenol,Z-hex-3-enyl acetate, E-2-hexenal and hexenal gave greater EAG responses than geraniol and 1-octen-3-ol. These results are also consistent with comparable data from adults. Newly hatched grasshoppers had similar EAG response profiles to plant materials and chemicals to those of adults, although the absolute EAG values of young hoppers were much lower than those of adults. Therefore, newly hatched hoppers were able to distinguish plants from an air control, and even host plants from non-host plants, and the feeding experience of hoppers probably has little influence on their subsequent ability as adults to identify and locate food plants.展开更多
The effect of temperature on the development of the Plutella xylostella （Linnaeus） （Lepidoptera： PluteUidae）, was evaluated at eight constant temperatures （10, 15, 20, 25, 28, 30, 32.5 and 35~C）, with relative ...The effect of temperature on the development of the Plutella xylostella （Linnaeus） （Lepidoptera： PluteUidae）, was evaluated at eight constant temperatures （10, 15, 20, 25, 28, 30, 32.5 and 35~C）, with relative humidity of 65% and a photoperiod of 14：10 （L： D） hours on two host plants, cauliflower, Brassica oleracea var. botrytis and cabbage, Brassica oleracea var. capitata. The low temperature threshold was estimated to be 7.06℃ and 7.84℃ and the thermal constant was 263.74 and 261.58 degree-days for P. xylostella on cauliflower and cabbage, respectively, using the linear model. Data were fitted to various nonlinear temperature-dependent models, and the low and high temperature thresholds, as well as the optimum temperature for development, has been estimated. Criteria of choice from the literature were used to evaluate models and to select the most suitable equation for P. xylostella development on each host plant. Conclusively, linear and Briere-2 models are recommended for the description of temperature-dependent development of P. xylostella on two host plants.展开更多
Chemosensory proteins (CSPs) are identifiable by four spatially conserved Cys-teine residues in their primary structure or by two disulfide bridges in their tertiary structure according to the previously identified ol...Chemosensory proteins (CSPs) are identifiable by four spatially conserved Cys-teine residues in their primary structure or by two disulfide bridges in their tertiary structure according to the previously identified olfactory specific-D related proteins. A genomics- and bioinformatics-based approach is taken in the present study to identify the putative CSPs in the malaria-carrying mosquito, Anopheles gambiae. The results show that five out of the nine annotated candidates are the most possible Anopheles CSPs of A. gambiae. This study lays the foundation for further functional identification of Anopheles CSPs, though all of these candidates need additional experimental verification.展开更多
Mulberry thrips Pseudodendrothrips mori (Niwa, 1908) is a major pest of mulberry trees recorded from different sericultural regions of the world. The thrips infestation affects the qualitative and quantitative charact...Mulberry thrips Pseudodendrothrips mori (Niwa, 1908) is a major pest of mulberry trees recorded from different sericultural regions of the world. The thrips infestation affects the qualitative and quantitative characters of mulberry leaf, by direct feeding damage to leaves and the ingestion of sap, which in turn affects the silkworm cocoon crop. This is most harmful in dry climates and seasons when heavily attacked plants lose moisture heavily. Under these conditions infestation can seriously deplete yields. The seasonal population fluctuation and the degree of damage caused to the host plant are influenced by various environmental factors including climate, host-plant variety, topography, soil type, and management regimes.This article attempts to review all available documents on mulberry thrips and to discuss the practical approaches for best control of this pest.展开更多
Photoperiodic sensitivity for diapause induction of the green lacewing, Chrysoperla sinica (Tjeder) was examined at 22℃. The adult diapause of C. sinica was induced by short-day photoperiods, and the critical photope...Photoperiodic sensitivity for diapause induction of the green lacewing, Chrysoperla sinica (Tjeder) was examined at 22℃. The adult diapause of C. sinica was induced by short-day photoperiods, and the critical photoperiod for its induction was between 12.5L-11.5D and 13L-11D.Adults developed without diapause under long-day conditions, and entered diapause under short-day conditions. The adult stage was the uppermost sensitive stage for adult diapause induction, adults could go into diapause only when the emerging adults were under diapause-inducing short-day photoperiods. The short-day photoperiodic experience by transferring between 15L: 9D and 9L: 15D at preimaginal stages did not result in adult diapause under 15L: 9D photo regime, although some treatments extended the pre-oviposition period in adult stage. The results showed that the 3rd instar larvae and pre-pupae were more sensitive to the photoperiodic change from 15L: 9D to 9L: 15D photo regime than the other preimaginal stages.展开更多
基金supported jointly by the grant of Project“973”:Fundamental Studies on Invasion and Control of Extra Pest(2002CB111400)the grant of Key Project of Ministry of Science and Technology of China:Development of New Technologies for Pest Forecasting(2001BA50PB01).
文摘Based on former studies on weather simulator modules in IPMist laboratory, study on visual programming of stochastic weather generator(VS-WGEN)was continued. In this study, Markov Chain, Monte Carlo, Fourier Series, and weak stationary process were used to generate the daily weather data in software Matlab 6. 0, with the data input from 40 years' weather data recorded by Beijing Weather Station. The generated data includes daily maximum temperature, minimum temperature, precipitation and solar radiation. It has been verified that the weather data generated by the VS-WGEN were more accurate than that by the old WGEN, when twenty new model parameters were included. VS-WGEN has wide software applications, such as pest risk analysis, pest forecast and management. It can be implemented in hardware development as well, such as weather control in weather chamber and greenhouse for researches on ecological adaptation of crop varieties to a given location over time and space. Overall, VS-WGEN is a very useful tool for studies on theoretical and applied ecology.
文摘Transgenic plants expressing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) were grown on over 22.4 million ha worldwide in 2004, nine years after their first commercial use in 1996. Insect resistance management (IRM) is critical for the sustainable use of Bt plants. Theoretical models suggest that plants expressing two dissimilar Bt toxins in the same plant have the potential to delay insect resistance more effectively than single toxin plants used sequentially or in mosaics. Transgenic cotton plants expressing two Bt toxins are now registered for use in the US and Australia, and several companies are developing new varieties of Bt corn, Bt cotton and Bt brassicas with dual Bt genes for commercial use in the coming years. We conducted two greenhouse studies using a unique model system composed of broccoli plants transformed to express different Bt toxins (Cry1Ac, Cry1C or both) combined with populations of diamondback moth, Plutella xylostella, carrying resistance to each Bt toxin, with over 20 generations of selection in each study. The results from the first study indicated that resistance to two-gene plants was significantly delayed compared to single gene plants deployed sequentially or in mosaics. The second study proved that using two-gene plants alone is better for sustainable IRM than concurrent use of one-and two-gene plants in the same region. These results have important implications for the development, deployment and regulation of transgenic insecticidal plants.
文摘Behavior and olfactory responses of grasshopper hatchlings, Melanoplus sanguinipes (F.), to odours from plant foliage and volatile compounds were tested using a glass Y-tube olfactometer and electroantennogram (EAG)techniques respectively. In single choice trials, newly hatched hoppers were much more sensitive to the odour from intact leaves and chopped foliage of ryegrass and wheat than other plants. Chopped sorghum leaves, but not stem-cut sorghum,were also significantly attractive. The orientation responses of grasshopper hatchlings to these plants were highly consistent with those of last instar hoppers and adults. When ryegrass was employed as the control, the odour from stem-cut alfalfa was more attractive. There was no significant difference in hopper orientation responses to the odours from chopped seedlings of sorghum, alfalfa, wheat or ryegrass.However, significantly more hoppers preferred the chopped ryegrass control to chopped Louisanna sage. Measurement of the EAG response of first instar hoppers to these plant odours showed that the odour of Louisanna sage elicited the greatest response amplitudes. In olfactory tests using different volatile components, Z-3-hexenol, E-3-hexenol,Z-hex-3-enyl acetate, E-2-hexenal and hexenal gave greater EAG responses than geraniol and 1-octen-3-ol. These results are also consistent with comparable data from adults. Newly hatched grasshoppers had similar EAG response profiles to plant materials and chemicals to those of adults, although the absolute EAG values of young hoppers were much lower than those of adults. Therefore, newly hatched hoppers were able to distinguish plants from an air control, and even host plants from non-host plants, and the feeding experience of hoppers probably has little influence on their subsequent ability as adults to identify and locate food plants.
文摘The effect of temperature on the development of the Plutella xylostella （Linnaeus） （Lepidoptera： PluteUidae）, was evaluated at eight constant temperatures （10, 15, 20, 25, 28, 30, 32.5 and 35~C）, with relative humidity of 65% and a photoperiod of 14：10 （L： D） hours on two host plants, cauliflower, Brassica oleracea var. botrytis and cabbage, Brassica oleracea var. capitata. The low temperature threshold was estimated to be 7.06℃ and 7.84℃ and the thermal constant was 263.74 and 261.58 degree-days for P. xylostella on cauliflower and cabbage, respectively, using the linear model. Data were fitted to various nonlinear temperature-dependent models, and the low and high temperature thresholds, as well as the optimum temperature for development, has been estimated. Criteria of choice from the literature were used to evaluate models and to select the most suitable equation for P. xylostella development on each host plant. Conclusively, linear and Briere-2 models are recommended for the description of temperature-dependent development of P. xylostella on two host plants.
文摘Chemosensory proteins (CSPs) are identifiable by four spatially conserved Cys-teine residues in their primary structure or by two disulfide bridges in their tertiary structure according to the previously identified olfactory specific-D related proteins. A genomics- and bioinformatics-based approach is taken in the present study to identify the putative CSPs in the malaria-carrying mosquito, Anopheles gambiae. The results show that five out of the nine annotated candidates are the most possible Anopheles CSPs of A. gambiae. This study lays the foundation for further functional identification of Anopheles CSPs, though all of these candidates need additional experimental verification.
文摘Mulberry thrips Pseudodendrothrips mori (Niwa, 1908) is a major pest of mulberry trees recorded from different sericultural regions of the world. The thrips infestation affects the qualitative and quantitative characters of mulberry leaf, by direct feeding damage to leaves and the ingestion of sap, which in turn affects the silkworm cocoon crop. This is most harmful in dry climates and seasons when heavily attacked plants lose moisture heavily. Under these conditions infestation can seriously deplete yields. The seasonal population fluctuation and the degree of damage caused to the host plant are influenced by various environmental factors including climate, host-plant variety, topography, soil type, and management regimes.This article attempts to review all available documents on mulberry thrips and to discuss the practical approaches for best control of this pest.
文摘Photoperiodic sensitivity for diapause induction of the green lacewing, Chrysoperla sinica (Tjeder) was examined at 22℃. The adult diapause of C. sinica was induced by short-day photoperiods, and the critical photoperiod for its induction was between 12.5L-11.5D and 13L-11D.Adults developed without diapause under long-day conditions, and entered diapause under short-day conditions. The adult stage was the uppermost sensitive stage for adult diapause induction, adults could go into diapause only when the emerging adults were under diapause-inducing short-day photoperiods. The short-day photoperiodic experience by transferring between 15L: 9D and 9L: 15D at preimaginal stages did not result in adult diapause under 15L: 9D photo regime, although some treatments extended the pre-oviposition period in adult stage. The results showed that the 3rd instar larvae and pre-pupae were more sensitive to the photoperiodic change from 15L: 9D to 9L: 15D photo regime than the other preimaginal stages.
