Current control methods for diamondback moth and other brassica insect pests and the prospects for improved management with lepidopteran-resistant Bt vegetable brassicas in Asia and Africa

The diamondback moth (DBM), Plutella xylostella (L.), remains a major pest of brassica crops worldwide. DBM has been estimated globally to cost US$ 1 billion in direct losses and control costs. Chemical control of this pest remains difficult due to the rapid development of resistance to insecticides and to their effect on natural enemies. These problems are especially severe in South Asia and Africa where lack of knowledge, limited access to newer and safer insecticides, and a favourable climate result in DBM remaining a serious year-round pest which substantially increases the cost and uncertainty of crop production. Despite these problems, application of synthetic insecticides remains overwhelmingly the most common control strategy. Biologically-based efforts to control DBM in Africa and Asia have focused strongly on parasitoid introductions. However, despite the identification and deployment of promising parasitoids in many regions, these efforts have had limited impact, often because farmers continue early-season spraying of broad-spectrum insecticides that are lethal to parasitoids and thus exacerbate DBM outbreaks. A significant driver for this pattern of insecticide use is the presence of aphids and other pests whose appearance initiates inappropriate spraying. Despite often extensive training of producers in farmer field schools, many growers seem loath to discard calendar or prophylactic spraying of insecticides. The introduction of an IPM technology that could replace the use of broad-spectrum insecticides for DBM and other key Lepidoptera is crucial if the benefits of parasitoid introduction are to be fully realised. The deployment of DBM-resistant brassicas expressing proteins from Bacillus thuringiensis could help to break this cycle of insecticide misuse and crop loss, but their deployment should be part of an integrated pest management (IPM) package, which recognises the constraints of farmers while addressing the requirement to control other Lepidoptera, aphids and other secondary pests.     

气候变化对湖南主要农作物种植结构的影响

基于湖南省97个地面气象观测站1961－2008年逐日平均气温、最高气温、最低气温、降水量、日照时数等气象观测资料,选择最佳小网格推算模型推算出500m×500m的高空间分辨率的网格序列资料;基于双季稻、油菜、棉花、柑桔、油茶、烟草等主要农作物生长条件及相关区划研究成果,确立相应农作物种植适宜性气候区划指标;结合地理信息资料,运用GIS技术,开展主要农作物种植适宜性动态气候区划。结果表明：气候变化对湖南主要农作物种植结构均有一定的影响,对双季稻的影响主要表现为熟性搭配区的变化,对油菜、油茶、柑桔的影响主要是最适宜种植面积增大,对棉花、烟草的影响主要最适宜种植面积减少。针对气候变化对湖南主要农作物种植适宜性的影响及相应农作物种植适宜性的气候区划结果,提出应对建议为：充分利用滨湖平原、河谷平原和盆地气候资源,扩大复种指数,提高单位面积产量;充分利用山地气候资源,做大做强湖南油茶产业;充分利用区域气候资源,打造湖南柑桔品牌;充分利用小气候资源,发展湘西、湘南特色烟叶。     

蔬菜作物化感作用及其利用

综述了蔬菜作物的化感作用及其作用机理,介绍了蔬菜作物对蔬菜作物或其他非蔬菜作物化感作用的研究现状,总结了蔬菜间化感作用的关系,指出了蔬菜作物化感作用的利用及其前景。     

甜菜夜蛾的化蛹场所及调查方法研究

根据野外实地调查经验,介绍了甜菜夜蛾在十字花科作物和百合科作物田块的化蛹场所及调查方法。以期为测报站等相关部门提供甜菜夜蛾蛹野外调查方法,为提高甜菜夜蛾预测预报的准确率奠定基础。     

Susceptibility of Cry1Ab-susceptible and -resistant sugarcane borer to transgenic corn plants containing single or pyramided Bacillus thuringiensis genes

Multiple independent trials were conducted to evaluate the performance of Cry1Ab-susceptible (Cry1Ab-SS), -heterozygous (Cry1Ab-RS), and -resistant (Cry1Ab-RR) genotypes of the sugarcane borer, Diatraea saccharalis (F.), on eight commercial hybrids and six experimental corn lines. The commercial varieties included two non-Bt and six Bt corn hybrids that expressed a single Bt protein (either Cry1Ab or Cry1F) targeting above-ground lepidopteran pests. The six experimental lines consisted of two non-Bt and four Bt corn lines, two expressing just the Cry1Ab protein and two containing the pyramided-genes Cry1A.105 and Cry2Ab2 (event MON 89034). Larval mortality on non-Bt corn leaf tissue ranged from 6 to 45% after 12 d across insect genotypes. The 12 d mortality of Cry1Ab-SS on leaf tissue of commercial Cry1Ab or Cry1F corn was 96-100%, whereas it was 80-96% for Cry1Ab-RS and 68-78% for Cry1Ab-RR. On intact plants, 39-64% of larvae survived on non-Bt corn plants after 21-25 d. Larval survivorship on intact plants of commercial Cry1Ab or Cry1F corn was 0-8.1% for Cry1Ab-SS, 1.3-34% for Cry1Ab-RS, and 19-51% for Cry1Ab-RR. Larvae of Cry1Ab-RR and -RS also caused significant plant injury to most of the commercial Bt corn hybrids, especially to the Cry1Ab corn. Cry1Ab resistance in D. saccharalis was incompletely dominant on commercial Bt corn hybrids. However, both experimental lines with pyramided genes of Cry1A.105 and Cry2Ab2 provided complete control of all three insect genotypes in both leaf tissue and intact plant tests. Results of this study suggest that MON 89034 should offer a means for Bt resistance management in D. saccharalis.     

天然橡胶产业供给安全研究

以环境要求相类似的橡胶、木薯、甘蔗、油棕为例,在探讨以上作物环境适应性和产量变化的基础上,对世界各主要产胶国的种植选择做出总结,提出中国天然橡胶产业供给安全对策,包括从政策上加大对小胶园的改造管理与扶持力度,进一步加大力度实施天然橡胶良种补贴,对天然橡胶实行指导价收购政策,建立胶农合作社,加强天然橡胶种植区域的基础设施建设等。     

京郊主要作物生产系统磷素养分平衡评价——以顺义区为例

[目的]评价北京市顺义区主要作物生产系统的磷素养分平衡状况。[方法]采用农田养分平衡模型,针对北京市顺义区主要作物生产系统（大田作物、果园和露地蔬菜）的磷素养分平衡进行了评价,并分析了农田磷盈余的主要影响因素。[结果]3种作物生产系统内均出现农田磷盈余现象,蔬菜生产系统农田磷盈余量[491.8 kg/（hm2·a）]显著高于大田作物[82.7 kg/（hm2·a）]和果园[129.5 kg/（hm2·a）]生产系统农田磷盈余量（P〈0.05）,然而后两者之间农田磷盈余量无显著差异（P〉0.05）。大田作物和蔬菜生产系统农田磷盈余量分别与化肥和有机肥磷输入量呈极显著正相关关系（r分别为0.987 7、0.970 1）,果园生产系统化肥和有机肥磷输入量与农田磷盈余量均呈极显著正相关关系（r分别为0.836 3、0.625 2）,但是各系统内作物收获磷养分量与农田磷盈余量不存在显著相关性（P〉0.05）。[结论]顺义区蔬菜生产系统磷素污染潜力较大;大田作物和蔬菜生产系统农田磷盈余量分别主要来源于化肥和有机肥的投入,而化肥和有机肥的投入均显著影响果园生产系统农田磷盈余量。     

中国热带作物产业发展的战略思考

为科学、高效和可持续发展热带作物产业提供参考依据,主要分析中国热带作物产业发展概况,并与世界热带作物产业进行比较,进而探讨热带作物产业发展的思路、目标,提出发展热带作物产业的3个路径选择：（1）国内适度规模发展,做精做强,建立和完善现代热带作物产业体系;（2）实施“引进来”战略,着力提高热带作物产业的综合生产能力;（3）实施“走出去”战略,合作开发境外热带作物资源,积极开辟国际贸易市场。     

麦类作物水肥耦合研究进展

简述了国内外近些年麦类作物水肥耦合研究的结果,总结了水肥耦合的含义、水肥耦合效应对麦类作物生长发育、产量,水肥利用率,光合及生理特性、土壤养分变化及作物品质的影响。提出了今后的研究方向。     

行间生草葡萄园土壤微生物量与土壤养分的通径分析

在酿酒葡萄(Vitis vinifera)园行间播种白三叶草(Trifolium repens L.)、紫花苜蓿(Medicago sativa L.)和高羊茅(Festuca arundinacea Schreb),以清耕为对照,研究了土壤微生物量、土壤微生物呼吸强度和土壤微生物熵的变化及其与土壤养分的关系。结果表明:与清耕(对照)相比,白三叶草和紫花苜蓿处理显著提高了土壤有机质、全氮含量,显著降低了速效磷含量;而高羊茅处理土壤有机质和速效钾含量显著低于清耕。白三叶草、紫花苜蓿和高羊茅处理土壤微生物量C含量分别比清耕增加65.2%,61.6%和6.7%;微生物量N含量分别比清耕增加53.6%,52.4%和15.0%。各生草处理土壤微生物熵均显著高于清耕,但土壤微生物呼吸强度与清耕之间无显著差异。微生物学指标总体与土壤有机质、全氮、碱解氮、速效钾呈显著或极显著正相关,与全磷和速效磷呈显著或极显著负相关。通径分析表明,碱解氮、全氮是影响土壤微生物量C、N和微生物呼吸强度、微生物熵重要的直接作用因子。