贵州省发现南美斑潜蝇为害小麦

贵州省发现南美斑潜蝇为害小麦南美斑潜蝇是我省１９９６年新发现的危险性害虫,属列入贵州省植物检疫对象补充名单的害虫之一。南美斑潜蝇以幼虫潜入叶肉为害,叶正反两面均可遭为害,虫道多沿叶脉弯曲、叶肉被食后成白色或褐色,从而影响作物的光合作用,受害叶片早枯脱...     

拉美斑潜蝇残留毒力测定法

拉美斑潜蝇(L.huidobrensis)属双翅目、潜蝇科,是一种重要的杂食性害虫,主要在温室或温暖地区为害蔬菜、花卉、装饰植物和杂草。因发现较晚,其生物学特征还不十分清楚。但它作为斑潜蝇的一个种,有其共性,如卵和幼虫都在叶肉内为害,幼虫发育期短,成虫小而灵活,这种共性给化学防治带来了很大困难。因为化学药剂可能杀死其天敌,而它却接受了一个不致死的农药剂量,刺激了它的生长,也促进了它对农药产生抗药性。但它也有个性,如为害特点、生命周期、对寄主植物的偏食性及对药剂的敏感性等,这些因素使适合其它种的综合治理策略不完全适合于它。如Macdonald 1991年比较三叶草斑潜蝇和拉美斑潜蝇对几类药剂敏感性时,发现适合防治三叶草斑潜蝇的综合治理策略要作适当修改才能适合于防治拉美斑潜蝇。因此,为了制定适合于拉美斑潜蝇的综合治理策略,     

斑斑蝇类害虫药效调查方法——查蛹法

斑潜蝇类害虫以幼虫在作物叶片内取食叶肉 ,计数其叶内幼虫的死活非常困难 ,以前所采用的一些调查统计方法 ,误差大不能真实反应药效 ,或调查太复杂、工作量大 ,在几年来的试验中 ,根据实际情况采用了查蛹法进行药效的调查统计 ,该法科学、准确、简捷 ,解决了难于确定斑潜蝇幼虫死活的问题 ,能很好地反映防治效果。现将查蛹法简介如下１试验原理美洲斑潜蝇和南美斑潜蝇幼虫老熟后爬出虫道在叶外化蛹 ,幼虫死亡后就不能化蛹 ,可根据化蛹量判断其幼虫的存活情况 ,从而评价药剂的防治效果。２药剂选择与处理设置斑潜蝇以危害蔬菜为主 ,应选择内…     

55%扑甲灵乳油对黄曲条跳甲的防效试验

正值2004年秋季,合浦县沿海一带天气干旱少雨,给生产带来了严重的损失,加上气候适合黄曲条跳甲(狗虱虫)的大量发生,对菜农来说无疑是雪上加霜。黄曲条跳甲食量大而杂,以甘蓝、白菜、萝卜、油菜等十字花科蔬菜为主,但也为害茄果类、瓜类、豆类蔬菜。其成虫食叶成孔洞而致枯萎,幼虫啃食根部,可使菜苗枯死,成虫善于跳跃,高温时还能飞翔,有假死的特性,因此对防治带来很大的难度。为了探索有效防治黄曲条跳甲的药剂,笔者引进扑甲灵等3种产品进行药效试验,取得了较理想的效果。现将试验结果报告如下。1材料与方法1·1供试药剂55%(扑甲灵)敌畏·马…     

拉美斑潜蝇的发生与防治

拉美斑潜蝇(Liriomyza huidobrensis)又称南美斑潜蝇是一种为害多种蔬菜和观赏植物的检疫性害虫,属双翅目(Diptera)、潜蝇科(Agromyzidae)、斑潜蝇属(Liriomyza)。1995年初,昆明动植物检疫局在云南口岸,从进口的农产品中截获,如果该虫传人我国,将对我国的农业造成重大损失,严重影响我国农产品的出口。美国就是因为对进口农产品检疫不当,使得该虫传人加利福尼亚州,然后又传到其它几个州,严重影响了当地的农业生产。拉美斑潜蝇最早是在阿根廷发现的,80年代初才被认为是属于新北区,或新热带区的昆虫。成虫利用产卵器将卵产于叶片,孵化后的幼虫在叶片中取食叶肉,使叶片产生坑道,影响植物光合作用,导致叶片枯萎,致使作物减产,农产品品质下降,甚至整株死亡。     

防治韭蛆药剂筛选试验

韭蛆是韭菜迟眼蕈蚊的幼虫,在地下部为害韭菜鳞茎和根,导致地上部叶片变黄枯死,一般药剂难以凑效,防治该虫是韭菜生产上的一大难题。根据保质、保产、保环境的要求,     

南美斑潜蝇成虫产卵特性分析

南美斑潜蝇Ｌｉｒｉｏｍｙｚａｈｕｉｄｏｂｒｅｎｓｉｓ是危害许多蔬菜和花卉的重要检疫性害虫,近几年在昆明地区已对蔬菜、花卉、造成严重危害。南美斑潜蝇对许多化学农药具有抗药性,单纯依靠化学防治难以控制。因此,摸清其生物学特性,掌握其发生危害规律,可更好地防治其危害。本文就拉美斑潜蝇成虫产卵特性进行分析,旨在为采取其它有效的防治手段提供参考。1　材料与方法1.1　芹菜:1997年4月4～6日,每天用一株芹菜供成虫产卵,虫量约100头,连续接虫3天,3株芹菜苗平均株高约20ｃｍ,按植株高度分上中下三层分别测量叶面积,采用Ｐａｒｒｅｌ…     

防治检疫性斑潜蝇田间药剂筛选试验初报

为及时找出高效、低毒、低残留的防治药剂 ,指导全省大面积生产防治。近几年 ,我站组织各地、州、市开展了防治检疫性斑潜蝇对路农药的筛选试验。１田间药效调查方法１．１查蛹法４次重复。每小区在施药前和施药后２４ｈ各采摘有虫叶片５～１０片（叶片数量根据作物而定 ,保证每样本幼虫数量在５０头以上） ,用塑料袋分别装好写明标签带回室内 ,于处理后第５ｄ ,７ｄ ,９ｄ各查１次 ,计数每袋内正常蛹个数 ,计算防效。要求各小区施药前后采摘叶片数量相同 ,受害程度接近 ,保证每样品活虫数量相当。１．２幼虫死亡率调查法在斑潜蝇幼虫１～２…     

不同色彩及改装的飞虫诱捕器对斑潜蝇的田间引诱性研究

通过测定不同色彩和改装的飞虫诱捕器对斑潜蝇的田间引诱效果,以实现更好的田间防治效果。在供试的6种诱虫板中,黄色板对斑潜蝇成虫的引诱力最强,紫色板和蓝色板对斑潜蝇成虫也有一定的引诱力,但比黄色板明显要差。在供试的8种双色诱虫板中,黄色+紫色板对斑潜蝇成虫的引诱性最好。黄色+蓝色板对斑潜蝇成虫也具有较强的引诱性,且与黄色+紫色板相比,其引诱力无显著差异。改装后的风吸式诱捕器安装在垄间与作物苗尖齐平的高处时,能显著提高诱捕器对斑潜蝇成虫的诱杀效果。     

辽西山区谷田5种叶甲发生规律及防治方法

叶甲科昆虫,又叫“金花虫”,幼虫和成虫绝大多数为害叶片。近年来,谷田叶甲在北方山区为害加重,食叶、蛀茎、咬根等。叶甲分布广,成虫为害期长,数量多,对幼苗为害严重。对叶甲应采取科学有效的防治策略,同时合理耕作,规避为害,提高植株的抗逆性或耐受能力。对为害较重的田块,除及时药剂防治外,还应补水、补肥,加快作物生长,减轻损失。     

福寿螺配偶个体大小选择性初步观察

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。     

Localization of metabolic sites of action of herbicides

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.     

厚朴病虫害种类的初步调查

采用标准地法和线路调查法,对湖北恩施市新塘乡双河厚朴基地的厚朴病虫害进行了系统调查,记录主要虫害13种,其中叶部害虫9种,枝干害虫2种,根部害虫2种。厚朴主要病害5种。藤壶蚧、厚朴枝角叶蜂和厚朴新丽斑蚜为湖北省首次报道,小绿叶蝉为厚朴新寄主记录种。同时记录了藤壶蚧的天敌6种,其中寄生小蜂2种,瓢虫4种;厚朴新丽斑蚜的天敌昆虫8种。对藤壶蚧、厚朴枝角叶蜂和厚朴苗木根腐病等重要病虫害的发生规律进行了初步调查,同时提出了防治建议。     

青稞种子带菌检测及杀菌剂消毒处理效果

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。     

百合地下害虫主要种类调查及生物（源）农药筛选

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。     

Effects of timing and method of application of Penicillium oxalicum on efficacy and duration of control of Fusarium wilt of tomato

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.     

Mode of action of meturine

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.     

Mode of action of etoxazole

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.     

Measures of durability of resistance

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.