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1.
Leek rust, caused byPuccinia allii Rudolphi, is an important disease of leek (Allium porrum L.) in the Netherlands. For the development of a practical sampling method for early detection of leek rust in commercial fields, information on the spatial distribution of the disease is necessary. In this study, the spatial distribution of diseased plants during three naturally occurring epidemics of leek rust was observed. The observations were analysed with the Black-White join-count statistic. The spatial distribution of rust-infected leek plants was different for each of the three epidemics, ranging from random to highly clustered. These results show, that in the development of a practical sampling method for detection of leek rust, it is necessary to take into consideration a possibly clustered distribution of diseased plants.  相似文献   

2.
采用浸渍法研究了分别取食韭菜、大葱、圆葱和大蒜的韭菜迟眼蕈蚊4龄幼虫对大蒜油、苦参碱和辛硫磷的敏感性,用生化分析法测定了敌敌畏和大蒜油对幼虫体内乙酰胆碱酯酶和主要代谢酶活性的影响.结果表明:大蒜油对取食韭菜、大葱、圆葱和大蒜4龄幼虫的LC50分别为825.14、1202.2、1274.3和1412.4mg/L;辛硫磷分别为0.5437、1.1921、1.7713和1.9224mg/L,两种药剂对取食大蒜和圆葱幼虫的毒力较取食韭菜的差异显著.取食大蒜和圆葱的幼虫较取食韭菜的其体内乙酰胆碱酯酶活力降低,羧酸酯酶的活力明显提高,谷胱甘肽-S-转移酶的活力也有一定提高.寄主植物所含的硫醚类化合物对乙酰胆碱酯酶和代谢酶的诱导或抑制可能是引起药剂敏感性差异的主要原因.  相似文献   

3.
美洲斑潜蝇的为害及生物学特性研究   总被引:5,自引:0,他引:5  
研究表明,美洲斑潜蝇的寄主植物主要有茄科、豆科、葫芦科,其次有十字花科、菊科、锦葵科等。受害严重的作物,平均单叶有虫道100.4个,单叶有幼虫46.3头,被害叶率达85.2%,有虫株率和被害株率均达100%;研究还表明,美洲斑潜蝇从植株下部开始为害,且以植株中上部虫量最多,而被害叶位多逐叶上移;通过室内饲养和田间观察获知美洲斑潜蝇在茄子、西葫芦和地芸豆上各虫态的发育历期,并描述了其习性  相似文献   

4.
ABSTRACT Arrhenotokous and thelytokous populations of Thrips tabaci from tobacco or leek plants were evaluated for their ability to transmit Tomato spotted wilt virus (TSWV) and for their host preference. Transmission efficiencies were comparatively studied using leaf disks of Petunia hybrida, Datura stramonium, and Nicotiana tabacum cv. Basmas. Adults of arrhenotokous populations collected on infected tobacco plants in the field were efficient transmitters (up to 48.5% transmission) and remained so when maintained on tobacco for several generations. Arrhenotokous T. tabacipopulations from leek plants were poor transmitters (up to 3.1% transmission), whereas no transmission was obtained with thelytokous populations from leek. All populations could infest leek, however none of the arrhenotokous and thelytokous populations from leek plants was able to infest tobacco. TSWV could be acquired by both first and second larval instars of a T. tabacipopulation from tobacco. However, the transmission by adults decreased with the age at which the virus was acquired by larvae. The highest efficiencies (61% of males and 51% of females transmitted) were obtained when newborn (0- to 24-h old) larvae acquired the virus. The majority of thrips started to transmit after becoming adult and rates were positively correlated with the temperature at which the thrips were kept. The median latent period values found for adults decreased with increasing temperature. The median acquisition access period (AAP50) of the population was 41 min, whereas the AAP(50) was 65 min for males and 35 min for females. The median inoculation access period of males was 246 and 365 min on tobacco and petunia, respectively, and 96 and 345 min for females. The results show that T. tabaci forms a complex in terms of host preference, reproductive strategy, and ability to transmit TSWV. The transmission parameters show that the thrips of arrhenotokous populations infesting tobacco are highly efficient vectors.  相似文献   

5.
In an effort to expand the spectrum of larvicides effective against the pea leafminer,Liriomyza huidobrensis (Blanchard), we studied the effects of a neem-based insecticide (Neemix-45) on the development of the leafminer under laboratory conditions. Bean plants were treated with a soil drench of 1, 5, 10 or 25 ppm azadirachtin or by dipping leaves in 1 or 15 ppm azadirachtin at various times before or during the development of the leafminer. Treating the plants with the neem insecticide before exposure to egg-laying adults had a greater effect on inhibiting the development of pupae and adult eclosion than treatment at the 1st-instar larval stage. The systemic effects from a soil drench had a greater adverse effect on pupation and adult eclosion than leaf dipping. Drenching plants with 1 ppm azadirachtin 24 h before exposure to adults had a greater effect (0% adult eclosion) than leaf dipping at the same time period and concentration (15. 6% adult eclosion). Similar results were obtained when drenching plants infested with lst-instar larvae with 1 ppm azadirachtin (11. 7% eclosion)vs dipping leaves at the same time period and concentration (44. 7% eclosion).  相似文献   

6.
In an effort to expand the spectrum of larvicides effective againstLiriomyza huidobrensis (Blanchard), the effect of spinosad was studied on the mortality of the leafminer under laboratory conditions. Bean plants infested with various leafminer stages (egg through third instar) were treated by dipping leaves in a liter of water containing 24, 48 or 96 mg a.i. spinosad or by drenching the soil of plants with 200 ml of water containing 12 mg, 24 mg or 48 mg a.i. spinosad. In general, leaf dipping was more efficacious and adverse effects were observed sooner than with soil drench. All concentrations of spinosad significantly reduced the number of adults that emerged except leaf dip of third instar; only the highest concentration caused significant reduction of pupae and adults. Spinosad would likely be a valuable insecticide for control of the pea leafminer,L. huidobrensis. http://www.phytoparasitica.org posting Nov. 4, 2005.  相似文献   

7.
Eight species belonging to the Family Cruciferae were classified to lafminer resistant, tolerant and susceptible on the basis of leafminer infestation. They were analyzed for the glucosinolate content and correlated with leafminer infestation. Total glucosinolate content in general and sinigrin content in particular appeared to have the ability to repel the attack ofLiriomyza brassicae, while gluconapin appeared to attract them. The percentage of infestation, the number of mines and the number of living larvae were estimated for evaluating the glucosinolate efficacy againstL. brassicae on cabbage.  相似文献   

8.
Eight species belonging to the Family Cruciferae were classified to lafminer resistant, tolerant and susceptible on the basis of leafminer infestation. They were analyzed for the glucosinolate content and correlated with leafminer infestation. Total glucosinolate content in general and sinigrin content in particular appeared to have the ability to repel the attack ofLiriomyza brassicae, while gluconapin appeared to attract them. The percentage of infestation, the number of mines and the number of living larvae were estimated for evaluating the glucosinolate efficacy againstL. brassicae on cabbage.  相似文献   

9.
The pea leafminer,Liriomyza huidobrensis (Blanchard), recently introduced into Israel, has proven to be extremely proliferous and difficult to control. It is a much more serious pest of vegetable and flower crops than the previously introducedLiriomyza trifolii (Burgess). Photosynthesis is reduced and cosmetic damage is incurred when adult flies stipple plant leaves with feeding punctures and larvae mine the leaves. This paper will review briefly the history, biology and potential control measures of the pea leafminer.  相似文献   

10.
BACKGROUND: Recently, the leafminer Cameraria ohridella Deschka & Dimic has caused heavy damage to the white‐flowering horse chestnut in Europe. Among the Aesculus genus, A. pavia L. HBT genotype, characterised by red flowers, showed an atypical resistance towards this pest. Its leaves, shaken in water, originated a dense foam, indicating the presence of saponins, unlike the common horse chestnut tree. The aim was to isolate and identify these leaf saponins and test their possible defensive role against C. ohridella. RESULTS: Spectroscopic analyses showed that A. pavia HBT genotype leaves contained a mixture of saponins, four of which were based on the same structure as commercial escin saponins, the typical saponin mixture produced by A. hippocastanum and accumulated only within bark and fruit tissues. The mixture showed a repellent effect on C. ohridella moth. The number of mines detected on the leaves of A. hippocastanum plants treated with A. pavia HBT saponins through watering and stem brushing was significantly lower than the control, and in many cases no mines were ever observed. CONCLUSION: The results showed that the exogenous saponins were translocated from roots/stem to the leaf tissues, and their accumulation seemed to ensure an appreciable degree of protection against the leafminer. Copyright © 2010 Society of Chemical Industry  相似文献   

11.
Abstract

Egg extrusion patterns were investigated as an inducible defensive mechanism in potato plants against the leafminer Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae). Increased multiplication rates in leaf cells surrounding an egg of L. huidobrensis leads to its exposure through the leaf cuticle, which might increase the risk of mortality. Extrusion rates were evaluated in laboratory tests, in relation to plant and leaf age in Solanum tuberosum L. var. Spunta. Stratified field sampling was also carried out in order to assess leafminer distribution on new and old leaves. Extrusion was higher in young plants, being restricted in older ones to new, still expanding leaves. Plant reaction was independent of egg density. In the field, damage was concentrated in older foliage, in line with the extrusion results. The relevance of egg extrusion for pest management is discussed.  相似文献   

12.
In a study carried out during 2002 and 2004 in Diyarbakıir and Mardin provinces, southeast Turkey, specimens were collected twice a month from cultivated and non-cultivated plants. Sixteen leafminer (Diptera: Agromyzidae) species were identified. Among them,Agromyza abiens Zetterstedt, 1848;Napomyza elegans (Meigen, 1830);Phytoliriomyza dorsata (Siebke, 1864); andPhytomyza aquilonia Frey, 1964 are new records for the Turkish leafminer http://www.phytoparasitica.org posting July 24, 2005.  相似文献   

13.
Increasing international trade in plants has resulted in repeated import of foreign pests into Belgium; Opogona sacchari and Coccotrypes dactyliperda are well known examples. Recently two new pests have been introduced into Belgium, Frankliniella occidentalis and Liriomyza huidobrensis. The thrips F. occidentalis appeared in the summer of 1987, and was first found in chrysanthemums. At present, this insect can be observed in floriculture, as well as in vegetable growing, where it occurs on a wide range of host plants. F. occidentalis is now considered definitely established in glasshouses in Belgium. At the end of 1989, the leafminer L. huidobrensis was found for the first time in Belgium. The damage was observed on chrysanthemums and lettuce. In 1990, this leafminer also attacked other crops, especially tomatoes and celery. Its distribution is still limited, as is the damage it causes.  相似文献   

14.
通过药剂水培法,研究比较了不同培养条件对7种新烟碱类杀虫剂在韭菜中的内吸性及其对韭菜迟眼蕈蚊Bradysia odoriphaga(Diptera:Sciaridae)4龄幼虫的毒力。结果表明:随着水培时间的延长,韭菜中7种杀虫剂对供试幼虫的毒力均呈增强的趋势,其中在100 mg/L下,噻虫胺和吡虫啉产生毒力作用较快,水培72 h时对幼虫的致死率分别为32.38%和36.50%,168 h时,呋虫胺的致死率最高,达96.35%;同一药剂在相同浓度下处理,内吸至韭菜叶部产生的致死作用快于内吸至假茎所产生的作用,并且致死率更高;水培温度及药液浓度越高,内吸后毒力产生越快,且致死率越高。表明新烟碱类杀虫剂可以通过韭菜根部处理防治咀嚼式口器害虫韭菜迟眼蕈蚊。  相似文献   

15.
不同寄主植物对美洲斑潜蝇种群参数的影响   总被引:4,自引:0,他引:4       下载免费PDF全文
在温度为25℃的实验条件下,测定了四季豆(红花架豆和红花地豆)、长豇豆和黄瓜等寄主对美洲斑潜蝇种群参数的影响。结果表明,除卵历期外,美洲斑潜蝇幼虫、蛹、卵-蛹历期、雌成虫寿命和生殖力在四季豆、长豇豆和黄瓜3种寄主植物上均存在极显著的差异(p<0.01),而在四季豆的两个不同品种上差异不显著(p>0.05)。美洲斑潜蝇在选择性强的四季豆上发育历期最短,化蛹率最高,雌成虫寿命最长、生殖力最高;在选择性差的黄瓜上发育历期最长,化蛹率最低,雌成虫寿命最短,生殖力最低。孵化率、羽化率和成虫性比在供试寄主间差异很小。  相似文献   

16.
Phytophthora porri was isolated from onion leaves causing leaf spots which resemble those of the white tip disease of leek. This is the first report of onion plants being attacked and damaged byP. porri.  相似文献   

17.
The tomato leafminer Tuta absoluta is an important insect pest of tomato crops worldwide. Biological control using entomopathogenic viruses such as isolates of Phthorimaea operculella granulovirus (PhopGV) can be a promising tool for suitably controlling this pest. However to date, few viral isolates from T. absoluta have been reported. Therefore, the aim of this study was to develop an economic, fast and accurate immunological technique for granulovirus detection and to evaluate viral presence in T. absoluta larvae from field samples collected in Colombia. Polyclonal antibodies against PhopGV were produced by using hens and rabbits. The production system in hen was selected as the most efficient and simple method. Then, a dot-blot test was developed, demonstrating the ability of antibodies to recognize granulovirus. Finally, granulovirus presence in 1186 T. absoluta larvae collected in the most important tomato production areas in Colombia was evaluated, and eight isolates were found in Boyacá and Cundinamarca (0.7% of occurrence). These results constitute the first report of a granulovirus isolated from T. absoluta larvae which had been naturally infected in Colombia's tomato producing-fields, and thereby validates the use of the immunological technique to detect granulovirus in field conditions.  相似文献   

18.
Neither Cladosporium allii nor C . allii-cepae was detected in seed samples of 46 commercial cultivars of leek and nine of onion.
In glasshouse tests where flower inflorescences of onions and leeks were dusted with conidia of C. alliicepae and C. allii , respectively, few onion seeds and no leek seeds became contaminated. In field crops of leeks some spathes and inflorescences became diseased and gave 0 002% C. allii contaminated seeds. No infected onion seeds were obtained from naturally-infected plants in the field.
Conidia of both fungi survived for less than 6 weeks in sterile and non-sterile soil (during which time the temperature varied from -8 to +11 C); pseudothecial bodies survived longer.
Both pathogens survived for 3 months in debris of onion or leek on the surface of soil in pots under similar conditions. In debris buried at a depth of 7 cm in sterile or unsterile soil they survived for 2 months. Although C. allii survived only 1 month in debris on the soil surfaces following a leek crop, conidia of the fungus were trapped from the air above the area for at least 6 months and healthy leeks transplanted into this area developed the disease. No leaf blotch developed in leeks grown on land which had not previously borne that crop.  相似文献   

19.
广东美洲斑潜蝇寄生性天敌初步研究   总被引:19,自引:2,他引:17  
曾玲  吴佳教 《昆虫天敌》1999,21(3):113-116
本文对广东菜区美洲斑潜蝇Lirionyza sativae寄生性天敌的种类及寄生情况进行了初步调查。结果表明,常见的美洲斑潜蝇寄生蜂有5种,其中以底比斯釉姬小蜂Chrysocharis rentheus和冈崎釉姬小蜂Chrysonotomyia okagakii为优势种。  相似文献   

20.
New mite-borne virus isolates from rakkyo,shallot and wild leek species   总被引:2,自引:0,他引:2  
Flexuous viruses were transmitted from rakkyo (Allium chinense) and wild leek species (especiallyA. commutatum) to plants of crow garlic (A. vineale), by transfer of dry bulb mites. By electron microscope decoration tests using three antisera and by inoculations onto test plants, it was concluded that from each of the two natural host species at least two viruses were isolated. The viruses from wild leeks are both pathogenic onAllium spp. and may be of economic importance. Decoration tests on a virus mixture from shallot obtained earlier, revealed another new mite-borne virus in this species. The mite-borne viruses ofAllium spp. appear to be very common; they are largely diverse and their identification remains difficult.  相似文献   

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