Evaluation of four entomopathogenic nematodes againstSpodoptera littoralis (Lepid., Noctuidae) larvae under different temperatures

The efficacies of four strains of entomopathogenic nematodes on infecting and killingSpodoptera littoralis were tested in the laboratory concerning soil temperature, nematode dose and emergence from the insect cadavers. All the tested nematodes attained almost 100% insect mortality at 4, 10 and 25 °C but at 35 °C,Heterorhabditis bacteriophora (HP88) achieved the least (64%). As soil temperature rise to 35 °C, the most adversely affected nematode in terms of recycling efficiency wasH. bacteriophora (EASD98) followed bySteinernema riobravis, H. bacteriophora (HP88) and finallyH. indicus (EAS59). Although all nematodes could infect and kill the host insects at 35 °C, those ofH. bacteriophora (EASD98) could not emerge from the cadavers. Differences in the numbers of emerging infective juveniles as related to nematode concentration and different degrees of soil temperatures were obvious and may be considered in developing a biocontrol strategy for the management of the cotton leaf-worm.With 4 tablesThis research was supported by the NARP project No. H-035 and is a part of a M. Sc. thesis by Mr. Atwa Ahmed Atwa.     

Evaluation of the effectiveness ofBacillus thuringiensis var.entomocidus as a pest control agent to replace chemical pesticides in alfalfa fields in Israel

The Egyptian cotton leafworm,Spodoptera littoralis Boisd., is the main important pest of alfalfa in Israel. Population levels of other pests usually do not reach the economic threshold. Nine chemical insecticide applications (7 spray applications and 2 granular fluorosilicate baits) were required to controlS. littoralis during the season of 1984 (in which infestation level was high) whereas only 5 applications of aBacillus thuringiensis var.entomocidus (Bte) preparation (3 sprays and 2 baits) produced the same effect. During 1983 and 1985 pest populations were moderate and only 6 chemical pesticide applications were required. A bait ofBte on wheat bran, Coax^®, developed in the present study was effective in the control of large larvae (instars 4–6). Hay yields of fields treated withBte were similar to the yields of a conventionally treated field. The best control of large larvae was obtained by applying the bait preparation under the wind row during the alfalfa cutting.     

江南油杉容器育苗基质筛选

用椰糠、泥炭土、塘泥、过磷酸钙和钙镁磷肥与南方普遍用作育苗基质的黄心土进行不同体积比或质量比混合作为育苗基质,开展江南油杉容器苗育苗基质试验,以期筛选出适合南方培育江南油杉的理想育苗基质.结果表明:育苗基质对江南油杉容器苗有较显著的影响,对苗木苗期的主要生长指标苗高、地径、根粗、保存率和生物量进行综合分析,筛选出较适合南方培育江南油杉容器苗的基质配方体积比为黄心土66.7％+椰糠33.3％,其次是黄心土50％+椰糠50％和黄心土80％+塘泥20％.     

Effect of storage temperature on the insecticidal activity of a wettable powder formulation ofBacillus thuringiensis var.israelensis onCulex pipiens molestus larvae

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.     

八种防霉剂对橡胶木和竹材霉菌及蓝变菌的毒性试验

霉菌和蓝变菌是橡胶木和竹材变质的主要原因之一。八种防霉荆对上述木竹材霉菌及蓝变菌的毒性试验结果表明：祛霉乐防霉剂对霉菌的最低抑制浓度为２～１０ＰＰｍ，和ＭＥＣＴ相当，对蓝变菌有特效，防治橡胶木或竹材霉菌和蓝变菌的最低有效浓度为０．２％，可替代五氯酚钠和进口防霉剂。     

北方酸枣种子质量实验室检测方法研究

对北方酸枣采用不同的种子预处理方法进行实验室质量检测。结果表明:经层积处理后砸破外壳(内果皮)取出种仁的酸枣种子,发芽速度快、出苗整齐、发芽时间短,此处理方法是酸枣种子理想的实验室质量检测预处理方法。     

Sustained-release formulations ofBacillus thuringiensis serotype H-14 and plastic formulations of Abate for long-term control of mosquito larvae

The larvicidal activity of sustained-release formulations ofBacillus thuringiensis H-14 (Bactimos briquets) and controlledrelease plastic formulations of Abate against mosquito larvae ofAedes aegypti (L.) has been evaluated. The test formulations provided continuous effective control with 90–100% larval mortality for several weeks. The presence of suspended soil constituents was associated with a lowering of larval mortality and tended to reduce the durations of effective control of Bactimos and Abate plastic pellets against mosquito larvae by about 1.8 and 2.2 times, respectively. Treatments with such formulations did not appear to prevent hatch of eggs which oviposited after application, but all newly hatched larvae failed to develop beyond the second instar.     

森林鼠害造成樟子松人工林林木生长损失量的评估

在遭受鼠害的樟子松人工林中随机选择67株被害样株,按危害程度分为0（对照）、I、Ⅱ、Ⅲ、Ⅳ、V6个等级,通过解析木分析,求出林木高生长与材积增长损失率。结果表明：林木高生长率与受害级别除v级以外呈负相关,受害级别越高,生长率越小,而受害第三年则相反。林木材积损失率与被害级别成正相关,被害级别越高,材积损失率越大;按年度分析,I、Ⅱ两级受害第二年损失率最大,Ⅲ、Ⅳ两级则持续逐年增高,V级在第二年即全部死亡;各受害年度不同级别的材积增长损失率曲线分别为：Y1=-3．950524＋53．117143X;Y2=-6．308095＋81．492857X;Y3=-11．019048＋87．191429X。     

Cycloartane glycosides from Astragalus plumosus var. krugianus and evaluation of their antioxidant potential

The methanol extracts of Astragalus plumosus var. krugianus Chamb. & Matthews afforded sixteen cycloartane glycosides among which krugianoside A, was never reported before. All compounds were evaluated for their cytotoxic activity in human skin fibroblast WS1 cells. For compounds exhibiting no significant effect on WS1 viability, the antioxidant potential was examined. Compounds 1 and 8 prevented elevation of ROS induced by t-BOOH, suggesting the potential activity of these compounds to protect fibroblasts from oxidative stress.     

樟子松人工林在辽东山区的生长评价

辽东山区20世纪80年代开始从内蒙古红花尔基引种樟子松营造人工林。20多年的实践表明,樟子松人工林在15 a生前生长较快;直径、树高连年生长量15 a生后呈下降趋势,20 a生后下降显著;直径、树高平均生长量20 a生后下降明显;15 a生前针叶量正常,而15 a生后针叶量明显下降,生长势弱,保存率低,纬度愈低生长愈差;生长量明显低于同龄的日本落叶松、红松,亦低于冷杉和云杉。因此,樟子松在辽东山区只适宜在较差立地上营造生态公益林,不宜作为培育用材林的树种。     

毛红椿优树自由授粉子代生长性状的早期测定

对来自3个省的58个毛红椿家系在安徽南陵进行了造林试验。3年生幼林的生长结果表明,毛红椿的树高、胸径2个性状在家系间均存在极显著差异;树高、胸径2个性状在不同重复间表现出极显著差异;毛红椿幼林期树高和胸径2个性状变异系数分别为21.1%和28.8%,其变异比较丰富,树高、胸径2个性状具有中等以上的广义遗传力。以树高和胸径为选择对象,选择出10号、15号、19号、27号和39号等5个在幼林期表现较为优异的家系。     

Antibiotic properties of the glucosinolates of Brassica oleracea var. acephala similarly affect generalist and specialist larvae of two lepidopteran pests

Glucosinolates may deter generalist insect feeding as their toxicity causes fitness damage, whereas insects specialized in brassicaceous plants may circumvent the toxic effect. By using no-choice leaf tests, we investigated whether larval development time, body weight, mortality and feeding rate of the generalist Mamestra brassicae (Lepidoptera, Noctuidae) and the specialist Pieris rapae (Lepidoptera, Pieridae), were affected by six genotypes of Brassica oleracea var. acephala, selected for having high or low concentration of sinigrin, glucoiberin (aliphatics) and glucobrassicin (indole). Two phenological plant stages were used. On young plants, M. brassicae most consumed the high sinigrin and low glucoiberin genotypes. Larvae weighed more on the high sinigrin plants. Development time took longer on the low glucoiberin genotype. On mature plants, consumption rate decreased on the high glucoiberin genotype. Larval weight decreased on the high sinigrin, glucoiberin and glucobrassicin genotypes, and development time increased with high glucobrassicin concentration. Pupal weight and mortality rate increased on mature plants, irrespective of the genotype. Pieris rapae fed most on young plants with high sinigrin, and larval weight increased on the high glucoiberin genotype. Mortality increased with low glucoiberin and low glucobrassicin. On mature plants, larval weight decreased with high sinigrin and glucoiberin. The high glucoiberin genotype was the less consumed and also induced a longer development time. High content of aliphatic glucosinolates offered mature plants significant antibiosis defence against both the lepidopterans, whereas the indole glucosinolate was marginally effective. Young plants were more consumed and increased larval weight likely because glucosinolate concentration was still not optimal.     

樟子松天然林资源的保护措施

樟子松(Pinus sylvestris var．mongolica)是我国北方珍贵用材、防护、绿化速生针叶树种，其天然林资源已呈渐危状态，因此，建立不同类型的樟子松天然林资源保护区具有重大的经济意义、生态意义和科学研究价值。     

樟子松优良家系选择

对大、小兴安岭及呼伦贝尔沙地4个产地的樟子松优树在4个地点进行了多年多点重复的半同胞子代测定。根据子代林定植后28年的观测结果,按着家系综合评定标准,对237个樟子松优树子代进行测定评选,评选出罕达盖优良家系11个,卡伦山产地优良家系14个,古莲产地优良家系4个,塔尔根优良家系3个,为建立高世代种子园提供优良物质材料,并为樟子松优良家系生产推广应用提供技术依据。     

河西绿洲樟子松育苗技术

针对酒泉地区开展樟子松育苗存在的许多不利自然因素条件，从圃地选择、整地作床、播种、苗期管理、越冬、壮苗培育等育苗环节，系统总结了河西绿洲樟子松育苗的技术措施与方法。     

野杏SSR-PCR反应体系优化

为建立稳定可靠的野杏SSR-PCR反应体系,以3个野杏无性系170号、240号、263号和1个西伯利亚杏无性系508号为试验材料,采用L16(45)正交试验设计对影响野杏SSR-PCR反应的5个因素在4个水平上进行优化。结果表明:各因素对反应体系的影响由大到小依次为DNA模板浓度、引物、dNTP、Mg2+、Taq聚合酶。野杏SSR-PCR最佳反应体系(总体积20μL):dNTPs 0.45 mmol/L、Mg2+2 mmol/L、Taq酶1.125 U、引物0.125μmol/L、DNA模板20 ng。选用引物X128和60个野杏样木对该体系进行稳定性验证,扩增产物集中在100～200 bp,稳定度高,多态性良好,该体系可应用于野杏分子标记辅助育种等方面的研究中。     

钟花樱组织培养再生体系的建立

对钟花樱组织培养再生体系进行研究,结果表明,BA／NAA约为10时,即取BA 0．8-1．0mg／L,NAA0．08- 0．1mg/L(单位下同),对芽的诱导有较好的效果,培养基组合为MS BA 1．0 NAA0．1。在芽的增殖与伸长方面,筛选出较优的培养基组合为1／2MS 6-BA 1．0 NAA0．1 GA30．5 肌醇25,芽的增殖系数为4．7,芽均高1．314 cm。在此基础上通过5次连续继代培养,芽的增殖系数达到了7．31,丛生芽诱导率81．0％。钟花樱根的诱导试验表明, 通过暗培养3 d,以1／2MS NAA 0．2 IBA 0．8 6-BA 0．01的培养成份组合最适宜根的诱导,生根率达90％。试验中低浓度的细胞分裂素6-BA对提高生根率是必要的。     

预防樟子松插穗干旱的方法

樟子松采穗最佳季节为母树休眠期和7月10－7月15日。在母树枝条上环割生根率可提高30％；插穗切口采取“劈切”，其生根率可提高12．5％。地温控制在20－25℃；插壤水分管理标准是PF值2，空气相对温度控制在85％以上，插床遮荫度控制在70％为宜。     

新疆杨芽接快繁新技术

新疆杨、银中杨是东北地区仅能栽培的白杨派品种。其抗性强,速生、干形好,树姿优美等特点,深受广大群众青睐。但由于新疆杨扦插繁殖困难,限制了该树种的大面积推广应用。用开原青杨、当地小钻杨作砧木,采用"丁字形芽接"和"嵌芽接"的方法培育新疆杨,比常规扦插苗繁殖快,成苗率高,适应性强,成本低,经济效益高,是充分利用有限的资源,快速繁殖新疆杨的好方法。     

南方红豆杉SSR-PCR扩增体系的建立

为了建立适合于南方红豆杉(Taxus chinensis var.mairei)种群遗传多样性分析的SSR-PCR扩增体系,在单因素试验确定各因素浓度范围的基础上,采用正交试验设计,对影响南方红豆杉SSR-PCR扩增的主要因素浓度进行了筛选。结果表明,南方红豆杉SSR-PCR最佳反应扩增体系为:20μL反应体系中含有1.50mmol/L Mg2++0.2 mmol/L d NTP+0.5U Taq DNA聚合酶+0.3μmol/L引物+75 ng DNA模板。