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近年来,鱼台县茄子栽培面积逐年扩大,2000年全县栽培面积达606hm2。茄子叶霉病发生较普遍,常年病田率20%~49%,为害损失逐年上升,成为本地区的主要病害。1症状茄子叶霉病主要为害叶片。先中、下部发生,然后逐渐向上蔓延。严重时也为害叶柄和嫩茎。叶片染病,叶片正面出现圆形或不规则形淡黄色褪绿斑点和斑块,叶背面病部生出霉层,初为白色,后渐变为紫灰色或灰褐色,霉层十分明显,为病菌的分生孢子梗和分生孢子。环境条件合适时,叶片正面的病斑上也可长出霉层。叶柄和茎部发病症状与叶部相同。2病原经镜检观测,… 相似文献
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叶用菾菜霜霉病过去在四川省未见报导,但1961年发现其为害较普遍。邛崃东安公社发病严重田块发病率达100%,死亡率达42%,雅安43—90%,天全15—100%。1962年调查蒲江发病率为5—100%,平均发病率为28%。受害植株叶形较健叶细小肥厚,质地脆硬,叶缘向后翻卷,心叶及幼嫩叶片出现褪绿症状。病株心叶部分往往成簇生状(图1),病叶背面有紫灰色霉层。留种植株发病时,花苔不能伸长而成短缩花茎,花、花苞都密集于茎上,被害部分显著褪绿呈肥厚现象,多不产生种球或产生很少(图2)。患病株易得軟腐病。 相似文献
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郁金香瘤瘿螨(Aceria tulipae Nalepa)1990年发现在我县小麦上发生,给小麦生产造成了一定的损失。郁金香瘤瘿螨在小麦拔节至灌浆期均可发生为害以孕穗至破口抽穗期为害最盛。小麦拔节期为害,心叶生长正常,主要为害心叶以下第2、3叶。孕穗至破口抽穗期主要为害剑叶和倒2叶。受害麦叶叶色褪淡,从叶片一边向内纵卷,为害轻的麦叶纵卷1/3至1/2,半边呈管状。为害重的叶片纵卷3/4 相似文献
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番茄病毒病是番茄上发生最普遍、为害最严重的病害之一,也是最难防治的病害。发病田块一般减产20%~30%,重者可减产50%以上。番茄病毒病还可使番茄品质下降,风味降低,严重影响经济效益,是番茄生产中的重大障碍。1田间主要症状1)花叶症状。叶片上出现黄绿相间或深浅相间的斑驳,明脉叶片略有皱缩,病株较健株略矮。露地番茄在5月中旬至6月中旬发生,春季温室里番茄发病以烟草花叶病毒(TMV)为主。2)条斑症状。在高温强光照条件下TMV与马铃薯X病毒混合侵染而产生。茎、果的病斑只发生在表皮组织上。3)蕨叶症状。由… 相似文献
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小麦细菌性条斑病是小麦上的主要病害之一。2000~2002年在塔额垦区大面积发生,3a受害面积4000hm2以上,小麦发病株率达85%~100%,平均病株率98%,减产20%~30%,并且造成品质和等级下降。1症状小麦细菌性条斑病主要为害叶片,其次是叶鞘、茎秆和穗。被害叶片初期呈水渍状半透明斑点或条斑,再沿叶脉向上下扩展,变成长条状,呈现油渍发亮褐色斑。湿度大时,可从病组织溢出黄白色菌脓,干缩后呈黄色菌胶粒。以抽穗和扬花期最重,使被害株提前枯死,穗形变小,籽粒干秕,造成减产。2病原及侵染循环小麦细… 相似文献
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1985年安大略省西南地区的马齿玉米和甜玉米发生了由细菌 Erwinia stewartii(E.F.Smith)引起的玉米细菌性枯萎病。在病叶上分离到的呈格兰氏阴性反应黄色的细菌,在渔宝接种到玉米苗上,引起了玉米细菌性枯萎病褪绿条斑的典型症状。通过对安大略省玉米发病的试验调查表明在 Essex 县和 Kent 县的玉米叶部呈中等至严重症状。在该省的较冷凉地区发病较轻。Essex 县的病害严重度比1984~1985年期间按冬季温度指数为77,比所预料的病害 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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调查了甘肃省临洮县为害百合的地下害虫种类, 并以主要发生为害种类为供试对象, 采用拌土法测定了几种生物(源)农药对主要害虫的室内毒力和致死中时。调查发现小云斑鳃金龟Polyphylla gracilicornis、棕色鳃金龟Holotrichia titanis为主要发生及为害种类, 不同时间发生种类存在差异, 9月份以小云斑鳃金龟幼虫发生为害为主, 发生量占地下害虫总数的66.16%, 平均种群密度为10.48头/m2, 10月份, 则以棕色鳃金龟幼虫发生为主, 发生量占地下害虫总数的96.86%, 平均种群密度为7.79头/m2, 主要取食百合根系和鳞茎, 造成根系数量减少, 鳞茎出现不规则褐色缺口或凹陷斑。药剂筛选结果表明, 1.8%阿维菌素乳油、200亿孢子/g球孢白僵菌粉剂对两种蛴螬均具有较高的杀虫活性和速效性, 药后7 d时, 校正死亡率在82.22%以上, 对小云斑鳃金龟幼虫和棕色鳃金龟幼虫的LC50分别为0.161、0.060 mg/g和5.558×107、0.362×107孢子/g, LT50分别为2.237 d(2.2 mg/g)、1.393 d(2.2 mg/g)和6.645 d(40.0×107孢子/g)、4.940 d(2.0×107孢子/g), 这两种生物(源)农药对两种蛴螬的LC50和LT50值均略大于两种化学农药25%二嗪磷乳油、40%辛硫磷乳油处理的, 且对小云斑鳃金龟幼虫的杀虫活性均低于对棕色鳃金龟幼虫的杀虫活性, 致死中时则长于对棕色鳃金龟幼虫的致死中时。 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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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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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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为了研究青稞种子外部和内部携带真菌情况,比较不同杀菌剂对青稞种子的带菌消毒效果和对幼苗生长的影响,为青稞种子播前包衣处理和种传真菌病害防控提供依据,采用离体平皿法对云南迪庆‘云青1号’、‘云青2号’和‘短白青稞’3个主栽品种进行带菌检测,并对种子进行拌种或浸种处理测定6种杀菌剂对种子消毒效果,分析杀菌剂对种子发芽和幼苗生长的影响。结果表明:供试青稞种子表面携带的优势菌群为青霉(Penicilliumspp.)、镰刀菌(Fusariumspp.);种子内部寄藏的真菌主要为镰刀菌、核腔菌(Pyrenophoraspp.)、附球菌(Epicoccumspp.)、丝核菌(Rhizoctoniaspp.)、链格孢(Alternariaspp.)和木霉(Trichoderma spp.)。青稞不同品种的种子表面及内部携带的真菌种类差异较大。致病性测定表明,镰刀菌对种子萌发和幼苗生长影响最大,后期出现幼苗坏死现象。45%咪鲜胺EW、75%百菌清WP、50%福美双WP对青稞种子携带真菌均有显著抑制作用和消毒效果,50%福美双WP消毒效果最优,达100%;45%咪鲜胺EW、75%百菌清WP、50%福美双WP处理对青稞种子发芽和幼苗生长均无显著影响。 相似文献
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