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唐养璇 《商洛师范专科学校学报》2002,16(1):80-82
核桃苗茎腐病（CyAospoza Julandiev la Ell et BasAh)已成为影响商洛核桃苗质量的一个主要因素；经调查发展：（1）核桃苗期茎腐病在商洛地区已普遍发生（有病病圃占调查圃的100％）。（2）苗期茎腐病的发病程度与核桃苗的栽植密度和苗圃地的耕作方式有直接关系，苗地密度大发病率则高，密度小则发病率低，苗地连作（核桃苗）的发病率高，隔年间作的则发病率低。 相似文献
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核桃苗期地下害虫是影响优良核桃苗木生产的主要因素之一.经调查发现:（1）核桃苗地地下害虫主要类群为金龟叩头虫甲（chckchafers and skipjacks）;（2）核桃苗地下害虫在商洛全区普遍发生并逐年加重;（3）地下害虫多,为害加重的主要原因是育苗连作,未腐熟农家肥的施用和防治不力. 相似文献
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唐养璇 《商洛师范专科学校学报》2002,16(2):50-52
核桃苗期地下害虫是影响优良核桃苗木生产的主要因素之一，经调查发现：（1）核桃苗地地下害虫主要类群为金电叩头甲（chckchafers and skipjacks）；（2）核桃苗地下害虫在商洛全区普遍性并逐年加重；（3）地下害虫多，为害加重的主要原因是育苗连作，未腐熟农家肥的施用和防治不力。 相似文献
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核桃生产是商洛地区林果三大主导产业之一,在我国的核桃生产中商洛地区占有相当重要的地位。年产量在历史上曾达到全国核桃年总产量的1/4—1/5、年出口量曾达全国核桃年出口量的1/6强。核桃的生产发展对商洛地区及全陕西省农村经济的发展有着非常重要的作用。但是,在近年来由于病虫害,树龄老化以及品种等方面的原因使全区核桃生产出现了严重的下滑和倒退。核果产量和质量逐年下降,截止目前,商洛核桃已丧失了国内市场的30％—50％和国际市场的60％左右。对商洛经济的发展已造成了巨大的损失。对此,我们进行了全面的调查,调查范围包括全区一市六县、十八个乡、三十四个自然村、三百零二户核桃栽种果农调查面积4300余亩调查总株数为21347竹从我们调查掌握的情况看商洛阳的区的核桃生产存在的问题不少在病虫害防止方面的问题尤为突出具体包括以下几个方面: 相似文献
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《河南职业技术师范学院学报(职业教育版)》2016,(5)
为研究粉红粘帚霉对玉米茎基腐病的抑菌防病作用,采用PDA平板和水琼脂对峙培养法测定粉红粘帚霉的抑菌作用,采用扣皿法测定挥发性代谢产物的抑菌作用,采用含毒介质法测定发酵液的抑菌作用,测定孢子液对玉米种子的促生作用,通过室内盆栽试验测定粉红粘帚霉的苗期防病效果.结果表明:粉红粘帚霉对玉米茎基腐病具有生防潜力.病菌菌落扩展受到明显抑制,粉红粘帚霉菌丝重寄生病菌菌丝,导致菌丝细胞原生质颗粒化、溃解;挥发性代谢产物对病菌菌丝生长无抑制作用;JM发酵滤液对病菌菌丝生长具有抑制作用,且第9天的抑菌活性最好,菌丝生长抑制率为50%;孢子液可以在一定程度上提高种子萌发率和单株鲜质量;粉红粘帚霉对苗期玉米茎基腐病具有一定的防病效果. 相似文献
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目的 为了综合控制白牡丹害虫危害,对商洛白牡丹苗期害虫区系及发生动态进行了研究.方法 采用随机抽样的方法在白牡丹种植园对害虫进行统计分析.结果 通过调查发现在商洛危害白牡丹幼苗的主要害虫共有18种,主要害虫种群为网目拟地甲、叶甲等.结论 商洛白牡丹害虫区系构成复杂且种群有较大波动. 相似文献
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玉米新组合茎腐病抗性鉴定的分析 总被引：2，自引：0，他引：2
本试验对56个玉米新组合采用田间人工接种玉米茎腐病菌(腐霉菌)的方法进行了抗性鉴定。结果表明,B-26和BJ1-58抗性最好,达到R(抗)水平,发病率分别为5.3%和10%;有19个组合达中抗(MR)水平,发病率在15%～30%之间。 相似文献
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对核桃苗期(实生苗)金针虫的危害现状做了全面调查并进行了大田防治试验,筛选出了以"胃毒诱杀"为主的防治方法,取得了显著的防治效果. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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唐芳 《读与写:教育教学刊》2008,5(6)
During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context. 相似文献