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麦长管蚜在思南县晚稻田大发生１９９５年１０月中旬，在思南县塘头镇双季晚稻田发现麦长管蚜大量聚集水稻穗部危害，这一现象属历史罕见。据１０月１６～１８日调查，发生一般的稻田，有蚜株率达１５％～２１％，百株蚜量７８０头～１３５０头；发生严重的稻田，有蚜株率... 相似文献
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2003年6月2日,在海门市德胜镇水稻育秧基地发现麦长管蚜[Sitobionavenae(Fabricius)]为害水稻叶片,使秧苗叶色轻度发黄。据调查,当时有蚜株率为62%,平均百株蚜量459.7头,最高百株1135头。麦长管蚜是长江中下游麦区麦蚜的优势种,也能使长江流域部分晚稻受害,但在海门市发现麦长管蚜为害水稻尚属首次。据调查,该田块为麦稻两熟,多年连作,品种为“5566”(安徽),育秧基地四周为成片的蜡熟末期小麦,未防治过蚜虫。分析麦长管蚜转移为害水稻的原因,可能是随着小麦逐渐成熟,麦长管蚜食料条件恶化,陆续就近迁入水稻育秧基地为害。普查本市其余稻区,… 相似文献
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笔者于1992年10月中下旬，在临川县湖南乡及七里岗乡二晚田（灌浆乳熟期）中，发现麦长管蚜Macyosipnumgranariumo的无翅成蚜（少数有翅成蚜）和若蚜群集于稻穗枝梗和谷粒脐部刺吸为害，每穗平均有蚜虫数60～70只，最高210只，同时也发现有蚜虫为害在处于抽穗打苞初期植株的茎秆基部，有蚜虫数平均100～120只，最多302只，为害轻者导致受害穗梗变褐，半凋萎，谷粒呈现褐色斑点。重者则使谷粒干瘪。茎秆变黑，具烟煤状物，对水稻产量及品质影响很大。麦长管蚜猖獗为害二季晚稻@吴德水$江西省抚州农校@方良$江西省抚州农校@许胜吉$江西省抚州… 相似文献
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1994年全州县种植晚稻44.3万亩,晚稻后期禾(黍)缢管蚜大发生,发生面积31万亩,占种植面积的70％。据调查,有蚜株率达50％～75％,一般每株有蚜量为25～40头,高的上百头,严重影响水稻正常生长,经积极防治后,仍损失稻谷约80万公斤。 9月下旬开始至10月中旬初,水稻灌浆至黄熟期,大量的成、若蚜集结在稻穗上,也有的集结在叶背、叶鞘上取食为害。蚜虫体 相似文献
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１９９５年崇义县晚稻稻蚜大发生１９９５年崇义县晚稻上稻蚜（麦长管蚜）继１９８３年以来又一次大发生。９月１１日调查，每兜虫量为２０～１３０只，一般为４０～６０只，均以若虫为多，群集在稻丛基部叶片上为害，据统计全县发生面积１０００ｈｍ２。９月２６日调查，... 相似文献
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麦蚜是我县沿江圩田三麦上重要害虫,尤以晚小麦受害更重。对其发生危害及防治进行了初步研究,结果报道如下。 一、麦蚜种类和发生特点 沿江圩田三麦上蚜虫有二种:禾谷缢管蚜(又名黍蚜)Rhopalosiphum padi[Linnaeus]及麦长管蚜Macrosiphum avenae[Fabricius]。 定点田系统观察结果:前期以麦长管蚜较多,后期禾谷缢管蚜所占比例逐渐上升,最高可占到99％以上(见表1)。 大田调查,禾谷缢管蚜比例占59.2—96.4％。禾谷缢管蚜所以能占绝对优势,主要因为这种蚜虫生长势强,繁殖速度快,5月下旬单个蚜虫繁殖平均达45只,而麦长管蚜虫只有4.2只。 相似文献
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1发生特点 松滋市是全国商品粮基地县(市),常年种植水稻近5．33hm^2。随着优质稻的推广,晚稻稻瘟病在丘陵山区发生逐年加重,近几年已上升为晚稻上的主要病害,特别是2004年晚稻穗颈瘟的发生为害给晚稻生产造成了较大损失。 相似文献
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福寿螺配偶个体大小选择性初步观察 总被引：7，自引：0，他引：7
通过野外观察与实验研究,掌握了福寿螺的婚配体制及其配偶选择性规律。福寿螺与多数低等动物一样,其婚配属于乱交制,无固定配偶;雌螺对与其交配的雄螺个体大小没有选择性,而雄螺对雌螺的个体大小有选择性,倾向于与较大个的雌螺交配。 相似文献
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F.M. Ashton O.T. de Villiers R.K. Glenn W.B. Duke 《Pesticide biochemistry and physiology》1977,7(2):122-141
Time- and concentration-course studies were conducted to determine the effect of thirteen herbicides on photosynthesis, respiration, RNA synthesis, protein synthesis, and lipid synthesis using isolated single leaf cells. Each herbicide was from a different chemical class. Appropriate 14C-substrates and product purification procedures were used for each process prior to liquid scintillation counting. The most sensitive metabolic site of inhibition was photosynthesis for atrazine, bromacil, dichlobenil, monuron, and paraquat; RNA synthesis for dalapon and dinoseb; protein synthesis for chlorpropham; and lipid synthesis for CDAA, chloramben, 2,4-D, EPTC, and trifluralin. However, with several herbicides, one or more process was almost as sensitive as the one mentioned above. All herbicides inhibited more than one process, and the most sensitive site of inhibition may not be the same process that was inhibited the greatest at the maximum concentration and maximum exposure time used. Therefore, a concept of metabolic sites of action, rather than a primary site of action, appears to be more meaningful for herbicides. 相似文献
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Effects of timing and method of application of Penicillium oxalicum on efficacy and duration of control of Fusarium wilt of tomato 总被引：3，自引：0，他引：3
The effects of timing and method of application of Penicillium oxalicum on the control of fusarium wilt of tomato were investigated. Application of P. oxalicum to tomato seedlings in seedbeds reduced disease caused by Fusarium oxysporum f.sp. lycopersici in a growth chamber by 45–49% and in glasshouse experiments by 22–69%. Disease suppression was maintained for 60–100 days after inoculation with the pathogen in the glasshouse. No disease reduction was observed in tomato plants where P. oxalicum was applied to seeds. Treatment with P. oxalicum did not affect the population of F. oxysporum f.sp. lycopersici in the rhizosphere. 相似文献
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E. LIMPERT B. C. CLIFFORD A. DREISEITL R. JOHNSON K. MÜLLER A. ROELFS C. WELLINGS 《EPPO Bulletin》1994,24(1):109-112
A variety of systems of designation has evolved to name pathotypes of plant pathogens. The systems were evaluated to determine those best suited for particular purposes. Virulence and avirulence/virulence formulae of pathotypes have advantage over the use of consecutive numbers or letters given in chronological order of pathotype discovery. As soon as pathotype information exceeds a certain level of complexity, mathematical codes are most advantageous, in particular two codes, octal notation and coded triplets. A more universal adoption of the most appropriate codes is recommended to ease communication and comparisons of results. 相似文献
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Christopher D. Keating Lindy M. Holden-Dye Robert J. Walker 《Pest management science》1996,46(3):263-266
The neuropeptide AF2 has a complex set of actions on the dorsal muscle strip of Ascaris suum, including a potentiation of the acetylcholine-stimulated muscle contraction. Caffeine at 100 μm and 5 mm inhibited this potentiation, as did 100 μm theophylline in two out of six studies. The cyclic-AMP-potentiating compounds IBMX, dibutyryl cAMP and forskolin had no effect on the AF2-induced potentiation of the acetylcholine-stimulated muscle contraction. These preliminary data suggest that the potentiating action of AF2 is not mediated by a cAMP pathway. 相似文献
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Magdalina I. Luzhnova Lyudmila M. Shekhtman 《Pesticide biochemistry and physiology》1975,5(3):205-210
The effect of meturine on the light processes of photosynthesis was studied.Meturine is a herbicide for weed control in potato and cotton crops. It is a N-phenyl—N-hydroxy—N′-methylurea.The experiments were carried out on isolated pea and spinach chloroplasts.When examining photosystem I, reduced DPIP was used as an electron donor, whereas methyl-viologen served as an electron acceptor. When examining photosystem II, DPIP represented the electron acceptor.The obtained experimental results have pointed to the absence of the effect of meturine upon the photoreaction I.Unlike N-phenyl—N′, N′-dimethylureas (CMU, DCMU) meturine has been a very weak inhibitor of photoreaction II.The authors explain the photoreaction II inhibition of chloroplasts from plants treated with herbicidal doses of meturine by conversion of N-phenyl—N-hydroxy—N′-methylurea into Hill reaction inhibitor(s). N-Phenyl—N′-methylurea can be one of such meturine metabolites.Meturine herbicidal action is accounted for by meturine transformation into Hill reaction inhibitor(s) in the plant tissues. 相似文献
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The mode of action of the 2,4-diphenyl-1,3-oxazoline acaricide/insecticide etoxazole has been argued to be moulting inhibition, but experimental results supporting this hypothesis are lacking. This study investigated the effect of etoxazole on chitin biosynthesis in the fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). Etoxazole induced moulting defects in fall armyworm larvae similar, if not identical, to those caused by benzoylphenylureas, a well-known class of insecticidal chitin biosynthesis inhibitors. Furthermore, in contrast to untreated larvae, the chitin content in the integuments of larvae several days after treatment did not differ from that in freshly ecdysed individuals, thus suggesting strong chitin biosynthesis inhibition in vivo. A more detailed investigation of the inhibitory potential by incubating cultured integument pieces from larvae of S. frugiperda with [14C]N-acetyl-D-glucosamine, a radiolabelled chitin precursor, revealed I50 values of 2.95 and 0.071 microM for etoxazole and triflumuron respectively. The incorporation of radiolabel into potassium hydroxide-resistant material was inhibited by etoxazole in a dose-dependent manner. Based on these results, it is concluded that the acaricidal and insecticidal mode of action of etoxazole is chitin biosynthesis inhibition. 相似文献
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ABSTRACT Conventional models for the durability of resistant cultivars focus on the dynamics of the frequency of resistance genes. This leads to a definition of the durability of resistance as the time from introduction of the cultivar to the time when the frequency of the virulence gene reaches a preset threshold. It is questionable whether this is the most appropriate way to measure durability. Here we use a simple epidemiological model to link population dynamics and population genetics to compare three measures of durability: (i) the expected time until invasion of the virulent genotype, by mutation or immigration, and subsequent establishment of a population (T(invasion)); (ii) the virulence frequency related measure of the time for the virulent genotype to take-over the pathogen population ( T(take-over)); and (iii) the additional yield, measured by the additional number of uninfected host growth days (T(additional)). Specifically, we show how the measures of durability are affected by deployment and epidemiological parameters. We use a combination of numerical solution and analytical approximation of a model for the population dynamics of avirulent and virulent genotypes of a pathogen growing in dynamically changing populations of resistant and susceptible cultivars. The three measures of durability are compared. Some consequences of the results for durable resistance in multilines and mixtures and the regional deployment of resistant cultivars are discussed. 相似文献