共查询到20条相似文献,搜索用时 78 毫秒
1.
棉蚜多以孤雌胎生蚜在室内花卉寄主上越冬,冬季窖藏石榴上的棉蚜卵能正常孵化,1月搭起的蔬菜大棚棉蚜末见发生;秋季至冬前,次生寄主棉田棉杆上的有翅孤雌蚜始终保持一定比例,棉田翻田耕后棉杆上棉蚜越冬卵未见存活,而立于地面棉杆上的越冬卵可孵化。下雪丧,原生寄主黄金树上有翅弧雌蚜基本消失,春季原生寄主与次生寄主上棉蚜卵的饱满率及其孵化率均较低。 相似文献
2.
小麦叶蜂在信阳一年发生一代。成虫初见于2月上旬,盛见于2月下旬到3月下旬;卵初见于2月中旬,盛见于3月上旬到4月上旬;幼虫五龄,初见于3月下旬,盛见于4月到5月上旬。以幼虫越夏,和以幼虫和蛹越冬。幼虫入土越夏深度在20cm以下的占97.5%。幼虫喜适湿度较干燥的环境中生存为害,四到五龄为暴食期。防治的有利龄期为三龄。在m ̄2内有三龄幼虫25头为防治指标。防治幼虫的有效农药有50%辛硫磷、50%甲胺磷、40%水胺硫磷以及4.5%甲敌粉等。 相似文献
3.
本文证明了羊角藓为枣铁倍蚜和蛋铁倍蚜新冬寄主,且寄生越冬率高,在溪沟两岸的岩面和灌丛粉岩土面,其枣铁倍蚜的寄生率比蛋铁倍蚜的寄生率高123%,在阴坡山地的石灰岩面和煤渣陀上的粘性土面,其蛋铁倍蚜的寄生率比枣铁倍蚜的寄生率高94.4%,羽化的有翅性母成蚜有较强的生命力,可迁飞上树正常产生干母,在红麸杨小叶上致瘿分别形成枣铁倍和蛋铁倍。 相似文献
4.
突缘拟凹背蝗生物学特性初步研究 总被引:1,自引:0,他引:1
突缘拟凹背蝗Pseudoptygonotus prominemarginis Zheng et Mao在云南大理地区1年发生1代,产于土中的虫卵于9月中,下旬开始孵化,卵期平均90.5d;蝗蝻5龄,历时184.5d,主要以3龄蝗蝻越冬;次年5月上,中旬开始羽化,不久即交配交卵,每雌虫平均产卵24.9个,成虫寿命18-23d,于6月下旬至8月上旬相继死亡,已知有多种天敌。 相似文献
5.
戈壁琵甲(鞘翅目:拟步甲科)生物学特性的研究 总被引:2,自引:0,他引:2
戈壁琵甲2年发生1代,世代不整齐,以成虫和不同龄期的幼虫越冬,成虫4月上旬至9月下旬产卵,卵期为8~12d.幼虫一般为12龄.幼虫期为1~1.5a.越冬幼虫于次年6月下旬至9月上旬化蛹.蛹前期为40~45d,蛹期为12~20d.羽化成虫后经280~300d性成熟,开始交配产卵,戈壁琵甲食性杂.不喜光.活动有明显的节律性.成虫具有利用防御腺进行自卫的特性,其防御腺分泌物可成为医学上的天然药物,该幼虫各项营养成分较高,是一种很有开发价值的昆虫资源。 相似文献
6.
落叶松球果种蝇生物学特性及防治的研究 总被引:1,自引:0,他引:1
落叶松球果种蝇在庙尔山地区一年一代或一年两代,以蛹在地被物下越冬。翌年5月初开始羽化,5月下旬产卵并出现幼虫,7月初幼虫老熟脱果落地化蛹。害虫发育与温度和寄主物候有相关性;成虫羽化始期是由4月10日算起积温达152℃的日期,日平均气温需达11℃左右,产卵始期日平均温度需达15℃,成虫羽化与雄花粉散落,产卵始期与种鳞开张,幼虫老熟与种鳞硬化具有一致性,防治试验表明;树冠喷洒40%氧化乐果乳油800倍 相似文献
7.
本文证明了羊角藓为枣铁倍蚜和蛋铁倍蚜新冬寄主,且寄生越冬率高,在溪沟两岸的岩面和灌丛粉岩土面,其枣铁倍蚜的寄生率比蛋铁倍蚜的寄生率高123%,在阴坡山地的石灰岩面和煤渣陀上的粘性土面,其蛋铁倍蚜的寄生率比枣铁倍蚜的寄生率高94.4%,羽化的有翅性母成蚜有较强的生命力,可迁飞上树正常产生干母,在红麸杨小叶上致瘿分别形成枣铁倍和蛋铁倍. 相似文献
8.
对杨叶锈病在上海的发生状况、病原菌冬孢子、夏孢子的形态及其越冬后的萌发和侵染能力进行研究。研究中未发现病菌的转主寄主,且冬孢子作用不明;在病叶上越冬的夏孢子能够萌发,用越冬夏孢子接种杨树可以导致发病。初步研究表明杨叶锈病在上海无转主寄主,初侵染源为病叶上越冬的夏孢子堆。 相似文献
9.
通辽地区捕食性瓢虫一年发生三或四代,3月上旬出哲,首先出现在易感蚜虫的植物上觅食,第一代发生于5月下旬~7月中旬,第二代于6月上旬发生,第三代于6月下旬发生,第四代于7月中下旬发生,世代重叠现象严重,9月下旬10月初以二、三或四代成虫越冬七星瓢虫、异色瓢虫越冬有群集性.捕食性瓢虫食性广,食量大,对蚜类发生有追随性,攻击取食,有卵食习性.温度、湿度、光照、风雨对成幼虫活动、取食、个体发育有影响.无孤雌生殖现象.捕食性瓢虫是本地区蚜虫等害虫的很好天敌,应加以保护. 相似文献
10.
苜蓿蚜在西宁1年发生10 ̄14代,主要为害蚕豆,以卵在蜀葵,酸模,苦苣菜等杂草根茎处或地表干枯的草籽荚壳上越冬。翌年4月温度达10 ̄12℃开始孵化,每雌平均产蚜量为30头,15℃左右完成一代需8 ̄10天,20℃左右只需3 ̄4天,取食为害季节无翅胎生雌蚜平均存活7天左右,孪斑瓢虫和蚜茧蜂是其主要天敌。 相似文献
11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness. 相似文献
12.
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly. 相似文献
13.
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well. 相似文献
14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation. 相似文献
15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。 相似文献
16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death. 相似文献
17.
Miao Maosheng 《华南师范大学学报(自然科学版)》2014,(6)
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula- 相似文献
18.
Yang Weitao 《华南师范大学学报(自然科学版)》2014,46(6):137-138
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re- 相似文献
19.
Bernard Kirtman 《华南师范大学学报(自然科学版)》2014,(6)
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that 相似文献
20.
《上海师范大学学报(自然科学版)》2014,(5):550
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with 相似文献