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Pemsl D.E.,Leibniz University of Hanover | Voelker M.,Leibniz University of Hanover | Wu L.,National Agro technical Extension and Service Center | Waibel H.,Leibniz University of Hanover
International Journal of Agricultural Sustainability | Year: 2011

Bt cotton has been cultivated in China for a decade. Studies have been conducted to assess theimpact on productivity and pesticide use. Limitations of these studies are the short time period considered and the reliability of data. This paper presents findings from monitoring 150 Bt cotton farmers in Shandong province in 2002 and 2005. Descriptive analysis reveals that pesticide use increased while seed price and Bt toxin concentration decreased. The Bt variable was consistently insignificant in the estimated production function with damage control specification and a fixed effects model. There is indication that poor standards in Bt varieties have caused this result. Due to market imperfections and emergence of a largely unregulated seed market for genetically modified crops, Bt toxin levels may be below the threshold required to effectively control target pests. Furthermore, rising cotton prices may have created additional incentive to increase pesticide applications. The emergence of secondary pests calls for further in-depth studies that should include local agro-ecological conditions. Our results indicate that farmers with more experience in Bt cotton cultivation apply less pesticides, confirming the findings of other studies that farmer knowledge and understanding of the Bt technology is an important condition for its success. © 2011 Earthscan. Source


Han Y.,China Agricultural University | Shan X.,National Agro technical Extension and Service Center | Zhu D.,China Agricultural University | Zhang X.,China Agricultural University | And 3 more authors.
Communications in Computer and Information Science | Year: 2011

This Paper is mainly focused on the Locust Data Collecting System based on Android platform, and designs the structure of data acquisition and data transmit system. The system includes data acquisition unit, data transmission unit and process unit in the server. In addition, the paper discusses the implementation of the Data Collection in mobile and the realization of the programming. The experiment indicates that the method is feasible and effective. © 2011 Springer-Verlag. Source


Feng H.,Chinese Academy of Agricultural Sciences | Feng H.,North Carolina State University | Feng H.,Henan Academy of Agricultural science | Gould F.,North Carolina State University | And 4 more authors.
Ecological Modelling | Year: 2010

The cotton bollworm Helicoverpa armigera (Lepidoptera: Noctuidae) is one of the most serious crop pests in northern China, calling for accurate prediction of pest outbreaks and strategies for pest control. A computer model is developed to simulate the population dynamics of H. armigera over a wide area in northern China. The area considered covers 12 provinces where serious outbreaks of H. armigera have been observed. In this model, pest development is driven by local ambient temperature, and adults migrate long distances between regions and select preferred hosts for oviposition within a region. Six types of host including cotton, wheat, corn, peanut, soybean and a single category composed of all other minor hosts are considered in this model. Survival rates of eggs and larvae are based on life-table data, and simulated as a function of host type, host phenology and temperature. The incidence of diapause depends on temperature and photoperiod experienced during the larval stage. Survival rate of nondiapause pupae is a nonlinear function of rainfall, and overwinter survival rate is a nonlinear function of temperature. Insecticide is applied when population density exceeds the economic threshold on a host crop within a region. Comparisons of model output with light-trap data indicate that our model reflects the pest population dynamics over a wide area, and could potentially be used for testing novel pest control strategies in northern China. © 2010 Elsevier B.V. Source


Zhang L.,Chinese Academy of Meteorological Sciences | Huo Z.-q.,Chinese Academy of Meteorological Sciences | Wang L.,Chinese Academy of Meteorological Sciences | Jiang Y.-y.,National Agro technical Extension and Service Center
Chinese Journal of Ecology | Year: 2012

Based on the 527 meteorological stations observation data as well as the diseases and pests data and planted crop areas data in China agricultural areas in 1961-2010, and by the method of correlation analysis, this paper analyzed the effects of the changes of meteorological elements on the occurrence of insect pests. Under the background of climate change, the mean annual air temperature and mean precipitation intensity increased at a rate of 0.27 °C·10 a-1 and 0.24 mm·(d·10 a)-1, respectively, while the annual sunshine hours decreased at a rate of 47.40 h·10 a-1. The annual precipitation intensity increased at a rate of 0.14 mm·10 a-1, but had great fluctuations. There were significant positive correlations between the rate anomaly of insect pests' occurrence area and that of mean annual air temperature and precipitation intensity. When the mean annual air temperature increased by 1°C, the increasing rate of insect pests' occurrence area would be 0.648, and the occurrence area would be increased by 0.96×108 hm2·time; when the mean annual precipitation intensity increased by 1 mm·d-1, the increasing rate of insect pests' occurrence area would be 0.713, and the occurrence area would be increased by 1.06×108 hm2·time. The rate anomaly of insect pests' occurrence area had a significant negative correlation with that of annual sunshine hours. When the annual sunshine hours decreased by 100 h, the rate anomaly of insect pests' occurrence area would be increased by 0.40, and the occurrence area would be increased by 0.59×108 hm2 time. Overall, the rate anomaly of insect pests' occurrence area had little correlation with that of annual precipitation, but significant negative correlations with the rate anomaly of mean annual small precipitation, days of micro-precipitation, and days of small precipitation. When the mean annual small precipitation, days of micro-precipitation, and days of small precipitation decreased by 1 mm, 1 d, and 1 d, the rate anomaly of insect pests' occurrence area would be increased by 0.014, 0.066 and 0.052, and the occurrence area would be increased by 0.02×108, 0.10×108, and 0.08×108 hm2·time, respectively. Source


Lu Y.,Chinese Academy of Agricultural Sciences | Wu K.,Chinese Academy of Agricultural Sciences | Jiang Y.,National Agro technical Extension and Service Center | Guo Y.,Chinese Academy of Agricultural Sciences | Desneux N.,French National Institute for Agricultural Research
Nature | Year: 2012

Over the past 16 years, vast plantings of transgenic crops producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) have helped to control several major insect pests and reduce the need for insecticide sprays. Because broad-spectrum insecticides kill arthropod natural enemies that provide biological control of pests, the decrease in use of insecticide sprays associated with Bt crops could enhance biocontrol services. However, this hypothesis has not been tested in terms of long-term landscape-level impacts. On the basis of data from 1990 to 2010 at 36 sites in six provinces of northern China, we show here a marked increase in abundance of three types of generalist arthropod predators (ladybirds, lacewings and spiders) and a decreased abundance of aphid pests associated with widespread adoption of Bt cotton and reduced insecticide sprays in this crop. We also found evidence that the predators might provide additional biocontrol services spilling over from Bt cotton fields onto neighbouring crops (maize, peanut and soybean). Our work extends results from general studies evaluating ecological effects of Bt crops by demonstrating that such crops can promote biocontrol services in agricultural landscapes. © 2012 Macmillan Publishers Limited. All rights reserved. Source

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