坝上高原地老虎种类和分布

为了澄清坝上高原地老虎种类,给防治工作提供依据,1984—1986年连续调查三年,获得大量标本,经西北农大卢筝先生签定,共隶属于16个属38种.其中以切夜蛾属Euxoa和地夜蛾属Agrotis种类最多,其次为鲁夜蛾属Amathes,狼夜蛾属Ochropleura,多为农作物上的主要害虫.具有东北,蒙新,青藏区的分布特点.查清其种类及为害,在生产上具有重要意义     

Physiological effect of chitinase purified from Bacillus subtilis against the tobacco cutworm Spodoptera litura Fab.

An extracellular chitinase was purified from Bacillus subtilis. The lethal concentration (LC₅₀) was determined by using chitinase in first, second, and third instars of Spodoptera litura Fab. Chitinase showed the highest insecticidal activity at 6 μM concentration within 48 h. The nutritional indices were also significantly affected by the 6 μM concentration (P < 0.05). Food consumption, efficiency of conversion of ingested and digested food, relative growth rate, and consumption values declined significantly while approximate digestibility was increased. Our study indicates that treatment of host plant leaves with the chitinase can regulate (reduce) larval growth and weight, and enhance the mortality. This may serve as an effective biocide and alternative to Bt toxin.     

Phenology and pest status of Agrotis segetum in a changing climate

Insects are strongly dependent on climatic factors, especially temperature. For this reason, changes in insect phenology are predicted to be one of the many effects of climate change. We analysed the effect of climate warming on Agrotis segetum (Denis & Schiffermüller) in Denmark. Agrotis segetum is an agricultural pest that causes root crop damage. Extensive registers of root crop damages by A. segetum in Denmark were kept between 1905 and 1980. These records show a correlation between A. segetum outbreaks and hot, dry summers. The last outbreak in Denmark, in 1976, prompted the implementation of pheromone trap monitoring. Data from these pheromone traps, for the periods between 1981–1991 and 1997–2009, show a decline in the number of A. segetum individuals during 2000–2009. We used this pheromone trapping data to test the hypothesis that temporal changes in phenology and abundance are correlated with temperature and precipitation patterns. As phenological fixed points, we use the time of capture (first, 10%, 50%, 90% and last) of 1st generation A. segetum together with the 10%–90% capture period and the total capture per location for a statistical comparison of the period 1981–1990 versus 2000–2009. We also analysed the effect of temperature on the timing of fixed points and the effect of precipitation on the mean total capture from the summer and the preceding winter. Our analyses showed an earlier occurrence of A. segetum during 2000–2009 than during 1981–1990: all phenological fixed points advanced by 6–9 days. Trap captures of the 1st generation roughly halved from the 1981–1990 decade to the 2000–2009 decade, and a much larger 2nd generation of moths developed in the latest decade. When a second generation occurs, populations in following years decrease because the larval offspring of the 2nd generation cannot successfully overwinter. Our analyses further indicated that increased precipitation during the summers and mild winters contributed to an overall decline in the populations of this pest. The presence of A. segetum remains sufficient to be a potential threat to yields. Forecasting an economically important attack of A. segetum is challenging because of the early emergence of A. segetum and more variable local weather conditions than 20 years ago; forecasting relies on the timely and correct delivery of monitoring results. Farmers are a vital source of information for monitoring, for estimating control requests and for timing the emergence of A. segtum. However, the growing frequency of no-risk forecasts has reduced the interest and lowered the motivation of farmers to participate in monitoring programs.     

转双价基因(Cry1 Ac+CpTI)抗虫棉(ZGK 9 71 2)对小地老虎抗虫性研究

室内测定了转 Cry1 Ac基因抗虫棉和转双价基因 (Cry1 Ac+Cp TI)抗虫棉对小地老虎的存活、生长发育、繁殖及营养效应的影响。结果表明 ,两种转基因抗虫棉对小地老虎幼虫均有一定的抗性 ,转 Cry1 Ac基因抗虫棉对低龄幼虫的抗性好于转双价基因抗虫棉 ,而转双价基因抗虫棉对高龄幼虫的抗性好于转 Cry1 Ac基因抗虫棉 ,但两种转基因抗虫棉对小地老虎幼虫的控制作用均不理想。两种转基因抗虫棉对小地老虎幼虫的生长发育、繁殖和营养效应均有较大的影响。表现为发育历期延长 ,虫重和蛹重减轻 ,羽化率、化蛹率、产卵量和卵孵化率降低 ;相对生长率、相对取食量、近似消化率、食物转化率和利用率明显降低 ,而相对代谢速率明显增加。转双价基因抗虫棉的影响更为明显