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《滁州学院学报》2018,(5):44-47
烟粉虱Bemisia tabaci (Gennadias)属微型刺吸式害虫,其形态和发育历期难以准确鉴别。本文利用NK-300体视解剖镜和扫描电镜观察烟粉虱成虫、各龄期若虫和卵的形态及各虫态的发育历期。结果表明,若虫随龄期的增加,虫体浑浊变化显著但红色复眼逐渐清晰。1龄若虫周缘有30-40根刚毛;2龄时刚毛消失,周缘可见少量缘齿;3龄时,缘齿最多,在取食点固定的最稳定;至4龄时,缘齿退化消失。在温度25±1℃,相对湿度60%-80%,光周期14L:10D下,用盆栽烟草饲养,各虫态历期为卵期7.08d,若虫期共14.92d,成虫期38.25d;各虫态存活率顺序为成虫>若虫>卵。 相似文献
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《安徽科技学院学报》2020,(2)
目的:以2代褐飞虱为例,探究不同波长对不同虫态不同性别的褐飞虱趋光性的影响,并确定2代长翅型成虫(♀♂)、2代短翅型成虫(♀♂)的趋光性和2代5龄若虫(♀♂)趋光性的最佳波长。方法:利用紫外分光光度计设置波长340、345、350、355、360、365、370、375、380 nm等9个波长处理来模拟测定大田自然散射光,分别对长、短翅型雌雄成虫(♀♂)和雌雄若虫(♀♂)的影响。结果:2代5龄褐飞虱雌雄若虫(♀♂)、2代短翅型褐飞虱雌雄成虫(♀♂)以及2代长翅型褐飞虱雌雄成虫(♀♂)的趋光性最佳波长范围均为360～365 nm;2代5龄褐飞虱雄若虫、2代长翅型褐飞虱雄成虫、2代短翅型褐飞虱雄成虫均比其雌性表现出对最佳波长具有较强的趋光性;2代褐飞虱趋光性强弱依次为:2代长翅型雌雄成虫(♀♂)﹥2代短翅型雌雄成虫(♀♂)﹥2代5龄雌雄若虫(♀♂)。结论:不同虫态和性别间的2代褐飞虱趋光性略有差异,不同虫态的雄性褐飞虱均比雌性表现出对最佳波长较强的趋光性;其趋光性强弱依次均为:2代长翅型雌雄成虫(♀♂)﹥2代短翅型雌雄成虫(♀♂)﹥2代5龄雌雄若虫(♀♂),但其趋光性最佳波长范围集中在360～365 nm。 相似文献
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张秀华 《闽西职业技术学院学报》2008,10(2)
单剂生物药剂及对各生物化学药剂进行正交试验设计的室内毒力测定,结果表明：单剂生物药剂0．6％阿维菌素水剂在敏感性和毒力上时2龄幼虫有较好效果：混合生物化学药剂室内药效试验的最优组合为16000IU／mg苏云金杆菌粉剂2000倍＋25％灭幼脲三号悬浮剂3000倍＋20％氰戊菊酯乳油30000倍．这两种药剂可选用于林间对幼虫的防治。 相似文献
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张秀华 《Journal of Zhangzhou Technical Institute》2008,10(2):26-29
单剂化学药剂和对各药剂进行正交试验设计的混合药剂的室内毒力测定结果表明,单剂化学药剂20％氰戊菊酯乳油和0．6％溴氰菊酯乳油在敏感性和毒力上对2龄幼虫有较好效果;混合化学药剂的室内药效试验的最优组合为20％氰戊菊酯乳油10000倍＋0．6％溴氰菊酯乳油4000倍＋80％敌敌畏乳油2000倍。这2种单剂化学药剂和一组混合化学药剂可选用于林间对幼虫的防治。 相似文献
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槭树绵粉蚧在甘肃庆阳地区1年发生1代,以3龄若虫越冬。以若虫和雌成虫吸食苹果树的叶片、嫩枝的汁液,在20年以上老果园内发生严重。采用诱集越冬虫态,铲除越冬场所,消灭越冬虫源,结合药剂防治能有效地控制其发生危害。 相似文献
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郑勇 《思茅师范高等专科学校学报》2007,23(6):14-17
胭脂虫（Dactylopius coccw Costa）具有重要的经济价值，其干体可制备成胭脂红，进一步提取胭脂红色素，广泛地用于食品染料、化妆品、药品等多种行业中。通过研究湿度对D．coccus孵化和生长发育的影响，在50％、70％、90％三种湿度条件下，观察了湿度对D．coccw孵化和种群生长发育的影响。结果表明，不同湿度对D．coccw卵的孵化、若虫及成虫的生长发育都有一定的影响，随湿度的增加，孵化量及孵化率增大，获得的一龄若虫数随湿度的增加而增加，二龄若虫和雌成虫数都是在90％RH时达到最大。说明高湿度对提高卵的孵化及种群生长是有利的。 相似文献
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不同杀虫剂对小麦蚜虫的防效研究 总被引：6，自引：0，他引：6
通过8种药剂对麦蚜的防效试验,结果表明:6%吡阿合剂乳油、10%吡虫啉乳油、3%啶虫脒乳油的速效性好;10%吡虫啉乳油、3%啶虫脒乳油、0.9%阿维菌素、6%吡阿合剂乳油、5%高效氯氰菊酯乳油、7.5%莫吡乳油的持效性好;6%吡阿合剂乳油、10%吡虫啉乳油、0.9%阿维菌素的长效性好.综合评价,6%吡阿合剂乳油、10%吡虫啉乳油的防效最好,其速效性防效在98%以上,持效性防效在98%以上,长效性防效在50%以上,3%啶虫脒乳油、20%苦皮藤乳油、5%高效氯氰菊酯乳油、0.9%阿维菌素和7.5%莫吡乳油处于中间水平,以上药剂的防效均高于对照药剂氧化乐果. 相似文献
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不同杀菌剂对蜡状芽孢杆菌的抑菌效果研究 总被引：1，自引：0，他引：1
采用抑菌圈法测定了4种杀菌剂对蜡状芽孢杆菌的毒力。结果表明,随着药剂浓度的增加,4种药剂对蜡状芽孢杆菌的抑菌率逐渐升高,其中800.0mg/L福美双、160.0mg/L农用链霉素和640.0mg/L申嗪霉素3种药剂在72 h的抑菌率分别达到94.3%、88.1%和82.0%,160.0mg/L中生菌素的抑菌率在48 h达到最高为78.0%。4种药剂对蜡状芽孢杆菌的毒力依次为农用链霉素中生菌素福美双申嗪霉素,其中农用链霉素和中生菌素的毒力较高,EC50分别为29.92 mg/L和50.69 mg/L。室内毒力测定表明农用链霉素和中生菌素是蜡状芽孢杆菌防控较为理想的杀菌剂。 相似文献
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虫生真菌的生物防治研究进展 总被引：1，自引：0，他引：1
首先从虫生真菌的资源分布论述,在我国已发现的昆虫病原真菌涉及40多个属400多种,其中虫草属真菌80种,捕食和寄生线虫的真菌10种,寄生昆虫的真菌215种,报道的新种有24种,生物防治中应用较广主要为绿僵菌、白僵菌和蜡蚧轮枝菌等;其次概述了入侵及致病机制,虫生真菌的入侵主要分四个阶段,入侵是机械压力和酶共同作用的结果.最后对毒力稳定性,菌株来源对同种昆虫毒力往往差异较大,同一菌株对不司寄主或同一寄主不同虫龄的毒力也有所不同.介绍了虫生真菌的发展的历史、研究现状与展望,对近年来我国虫生真菌的生物防治研究进展也进行了概括. 相似文献
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利用莱氏野村菌对亚洲玉米螟二龄幼虫的室内毒力测定,最高死亡率达86.52%,致死中时间为5.62d,致死中浓度为7.93×105个/ml.莱氏野村菌对亚洲玉米螟幼虫具有较强的毒力效果. 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