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斜纹夜蛾属鳞翅目夜蛾科,是一种间歇性暴发危害的害虫。自90年代以来,由于其暴发频次高、危害大,已上升为本地桑树的主要害虫。为了科学地监测预报斜纹夜蛾的发生情况,抓住有利时机,有效防治桑园斜纹夜蛾,近两年笔者对桑园斜纹夜蛾的发生规律及防治方法进行了初步探讨。 相似文献
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为了筛选适于草坪害虫斜纹夜蛾（Prodenia litura）防治的绿色农药,采用浸叶法测定比较了5个不同化学类别共20种绿色杀虫剂对斜纹夜蛾3龄幼虫的室内活性。结果表明,7种常用农用拟除虫菊酯类杀虫剂的杀虫效果不及常规有机磷农药毒死蜱,而2种新型拟除虫菊酯四氟醚菊酯和四氟苯菊酯的杀虫效果相当或优于毒死蜱;苯甲酰脲类药剂虱螨脲、氟啶脲和氟铃脲,双酰肼类虫酰肼,杂环类茚虫威和虫螨腈,以及生物源类杀虫剂甲氨基阿维菌素苯甲酸盐7种药剂对斜纹夜蛾的活性高,均符合绿色无公害农药的基本要求,是值得进一步试验开发用于草坪斜纹夜蛾等夜蛾类害虫防治的候选药剂。 相似文献
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斜纹夜蛾是一种分布广、食性杂、间歇性暴发的害虫,不但在桑叶上危害,而且在棉花、蔬菜、山芋、黄豆等多种作物上危害,桑园靠近这些作物的田块极易暴发,严重影响蚕桑生产。1发生原因1.1认识上的错位。斜纹夜蛾成虫产卵时,成堆产在叶背上,幼龄幼虫集中在叶背啃食叶肉,仅留下表皮,2龄后分散为害,将叶吃成孔洞、缺刻。斜纹夜蛾世代重叠,一年发生4～5代,在2龄前如果不注意摘除卵块和捕捉幼虫,或忽视药剂防治,后期将有可能暴发成灾。1.2防治上的死角。斜纹夜蛾高龄幼虫无论使用那种农药,效果均不理想,虽说桑园现在都是集中连片,但组织统一防治难… 相似文献
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斜纹夜蛾属鳞翅目夜蛾科,是世界性分布的暴食性害虫,为害十字花科、茄科、葫芦科、豆科及粮、棉等99科290多种农作物.斜纹夜蛾食性广,繁殖快,长江中下游地区在20世纪90年代以来几乎连年暴发成灾,已成为十字花科蔬菜、城市绿化地花草的最主要害虫之一.斜纹夜蛾在桑树上间歇暴发为害,严重影响蚕桑生产.长期以来化学药剂的大量使用,不仅使害虫的抗药性增强,而且对生态环境带来了很大影响.在桑树上应用农药防治,更易引起家蚕中毒,造成蚕茧减产. 相似文献
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2007年是斜纹夜蛾在海安县有史以来在桑园内发生量最多的一年,危害严重,损失较大。2008年,为有效控制斜纹夜蛾在桑园内危害,海安于8月上旬及时发出虫情报告,研究部署防治策略,贯彻落实技术措施,取得了较好的防治效果。 相似文献
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修饰羟基可提高大多数抗菌药物的药效,研究中一般对羟基进行以下4种修饰：酰化为酰胺或酯类;烷化或烷氧化;用卤素取代;直接将羟基去除.经这些修饰后,可起到增强抗菌活性、对抗耐药性、方便制剂的作用,但羟基的修饰并非对所有的抗菌药物都是有利的,所以在修饰羟基时应视具体情况而定. 相似文献
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《蚕桑通报》2003,(4)
题目期(页)桑树桑树转基因植株的叶片蛋白质含量分析1(14)桑螟对氨基甲酸酯类农药的抗性调查1(20)过度用药诱发桑园叶螨成灾原因分析1(43)山区载培农桑品种冻害及其防御技术1(47)新一代桑品种产质量比较试验2(16)毒死蜱取代甲胺磷防治桑园害虫效果探讨2(20)桑园省力化栽培试验2(29)桑树嫁接体育苗的生产应用及技术要点2(34)夏季桑树小苗移栽新技术2(51)桑树的夏季芽接技术2(54)袋接体塑料薄膜小拱棚建园技术应用简报2(55)丘陵山地栽种果桑大10的主要技术2(57)桑花叶病病原及化学药剂治疗的研究3(13)我场桑园主要病虫害的综合防治3(42)杭州市… 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献
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以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献