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1.
The aim of this research was to compare the effectiveness of mineral oil with rapeseed oil in the protection of potato seeds against Potato virus Y (PVY) and Potato virus M (PVM) infection. The research was carried out under field conditions in the north of Poland, in the Department of Potato Protection and Seed Science of the Plant Breeding and Acclimatization Institute??National Research Institute at Bonin. The effects of oil protection on potato seed infection by viruses, yield, and its structure and phytotoxity were assessed. Two rapeseed oils and one mineral oil were used: Olejan 85 EC (85% of natural rapeseed oil), alimentary oil Marlibo (100% of natural rapeseed oil) and Sunspray 850 EC (98.8% mineral oil+1.2% emulsifier). The effectiveness of oils in protection against PVY and PVM tuber infection was tested on two cultivars (Clarissa and Rosalind), which have a different level of resistance to the two viruses. The assessment of phytotoxicity was carried out on 10 potato cultivars from different earliness groups (Augusta, Bryza, Cekin, Clarissa, Impala, Krasa, Rosalind, Satina, Velox). Two oil concentrations, 2% and 4% were applied. During the growing period, eight to nine oil treatments were applied at 7-day intervals. The effectiveness of rapeseed oils against PVY and PVM was much weaker than that of the mineral oil and for the susceptible cultivar the percentage infected tubers did not differ significantly from untreated crops. However, Olejan 85 EC deserves attention as it significantly reduced PVY infection across years in the more resistant cultivar, especially in the case of a lower concentration (2% vs. 4%). When there are no other means of protection to use on organic seed plantations, this oil can be used as an alternative, especially in the case of cultivars which are moderately resistant to PVY. A disadvantage of its application may be the fact that in some years symptoms of phytotoxicity on potato plants were recorded and a lowering of tuber yield.  相似文献   

2.
In the 2014 and 2015 crop seasons, the efficacies of different types, rates and combinations of mineral oil and insecticide foliar sprays for reducing Potato virus Y (PVY) spread were tested in controlled field trials in New Brunswick (NB), Canada. Experimental plots were planted with certified PVY-free Goldrush, supplemented with known virus-infected seed to raise PVY inoculum to 2.3% and 3% at the beginning of the 2014 and 2015 seasons, respectively. Treatments consisted of mineral oil-only sprays at different application rates, insecticide-only sprays of differing numbers, and several combined mineral oil and insecticide spray regimes, all compared to a no-spray control treatment. PVY spread to 18% (2014) and 22% (2015) of initially virus-free plants in no-spray control plots, with significant reductions observed in PVY spread in several treatments. Greatest PVY reductions, as low as 4% (2014) and 12% (2015), were in combined mineral oil and insecticide spray treatments, followed by oil-only sprays; while insecticide-only sprays did not significantly reduce PVY spread. As well as measuring PVY spread to marked test plants and randomly collected post-harvest tuber sample from the plots, exhibited similar treatment pattern for PVY incidence. Multiple logistic regression modeling confirmed the relative efficacy of combined oil and insecticide sprays for reducing PVY spread, while accounting for variable inoculum and aphid factors. Modeling also highlighted the importance of planting low-PVY seed initially, and of early application of foliar sprays. Local best management practice recommendations for reduction of in-field PVY spread were discussed.  相似文献   

3.
Potato virus Y (PVY) is a major pathogen of potato and transmitted non-persistently by aphids. Aphis fabae is the main vector of PVY in the High Grade Seed Potato Production Area (HG area) in Finland, where the number of aphids and infection pressure with PVY are rather low, but problems with PVY occur in PVY-susceptible cultivars. The aim of the study was to test straw mulch, mineral oil, birch extract, and insecticides for control of PVY in small-scale field experiments and, additionally, at farm level in growers’ fields in the HG area of Finland. The insecticide esfenvalerate reduced the incidence of PVY in the progeny tubers by 29% in one of the 3 years, whereas other chemical treatments or birch extract had no significant effect on PVY incidence. Spraying foliage with mineral oil (Sunoco 11 E/3) reduced the incidence of PVY in 2 years by 43 to 58%, respectively. Straw mulch spread to the field at the time of plant emergence reduced PVY incidence in all 3 years by 50–70%. At farm level, straw mulch reduced the incidence of PVY in the progeny tubers by 25–47%, respectively, in both years tested; however, combining application of straw mulch and mineral oil did not further reduce incidence of PVY. Successful control of PVY in the HG area of Finland using straw mulch may be explained by transmission of PVY early in the growing season at the time of plant emergence and the relatively low number of vector aphids.  相似文献   

4.
Field potato plants sprayed with a mixture of a pyrethroid (cypermethrin at 40 g a.i./ha) and a paraffinic oil (Sunoco Sunspray 7E at 7 l/ha) were colonized by fewer aphids and were less frequently diseased by potato virus Y (PVY) than unsprayed plants or plants sprayed with either cypermethrin or the oil alone; aphids given access to leaves of PVY-infected field plants sprayed with the mixture were also less likely to transmit PVY to laboratory test plants than aphids given access to leaves of plants sprayed with either chemical alone, or to untreated leaves. When alate aphids were confined above virus-infected and healthy plants, combined oil and cypermethrin treatment also gave greater protection against virus inoculation than either chemical alone. Electrostatic charging of spray droplets increased chemical deposits on field plants, especially when the plants were small and on upper leaves. These greater deposits improved control of PVY by the oil and the cypermethrin, individually or in combination, and enhanced the aphicidal action of the cypermethrin.  相似文献   

5.
Tests were made at Presque Isle, Maine, from 1963 through 1965 to measure the effect of oil sprays on the spread of potato virus Y (PVY) in Green Mountain potatoes. In 1963, 4 weekly applications of a 1% mineral oil emulsion at 1.25 gal oil/acre(4.71/.41 ha) did notaffect significantly (P = 0.05) the spread of PVY. In 1964, the 64% control of PVY spread from 5 weekly applications of mineral oil emulsion at 1.25 gal/acre was not significantly different at that level from the 55% control from 5 weekly applications of the oil emulsion at 2.5 gal/acre (9.5 1/.41 ha). Three or 5 weekly applications of an alkylated naphthalene (Velsicol AR-60®) spray at 1.25 gal/acre significantly increased spread of PVY compared to that from 5 applications of the oil at 1.25 or at 2.5 gal/acre. In 1965, from 69 to 75% control of PVY spread resulted from 6 weekly applications of a paraffin oil emulsion at 2.5 gal/acre. The percent spread from the 6 weekly applications was smaller, but not significantly so (P = 0.05), than from 3 weekly applications made during the first half of the same 6-week period. In these tests, relatively light spread of PVY occurred, and control of spread was rather variable but the results indicate that oil emulsion sprays offer promise for protecting potato plants from PVY infection.  相似文献   

6.
The focus of this study was to evaluate two mineral oils (Superior 70 and Vazyl-Y) in reducing the seasonal spread of Potato Virus Y (PVY). Three concentrations of oil (0, 5, and 10 L ha?1 of Superior 70; 0, 7.5, and 15 L ha?1 of Vazyl-Y) and three spray regimes for both oils (every 3–4, 7, and 10–11 days) were tested. Two weeks after top-kill, two tubers from each of 49 plants free of virus at emergence were harvested from treatment plots, sprouted, and tested for PVY with enzyme-linked immunosorbent assay (ELISA). Results revealed that in the case of Superior 70, PVY spread in mineral oil treated plots ranged from 2.1 to 12.2 %, while in the control plots it ranged from 20.4 to 37.7 % across three cultivars. In the case of Vazyl-Y, PVY spread in mineral oil treated plots ranged from 2.1 to 26.5 %, while in the control plots it ranged from 49.9 to 85.7 % across three cultivars. These data show that there was a significant reduction in PVY due to spray of mineral oils. In addition, mineral oil was quantified in plants from the Superior 70 treated and the control plots to understand the dynamics of mineral oil during the season. While there was little to no oil measured in the leaves at the early stages of plant growth, a considerable amount of mineral oil was detected close to plant maturity. A basic model of the concentration of oil in the treated foliage was formulated to confirm our understanding of the factors at play. The model could explain from 50 to 90 % of the variation in oil content observed in the field. Plant growth and size are important factors affecting oil content in mineral oil treated foliage.  相似文献   

7.
The aim of this research was to assess the rate of increase in the level of tuber infection by PVY, PVM, and PLRV during three consecutive years of multiplication in the field for 17 new cultivars registered in Poland in 2009–2011 and for two cultivars not listed in the registry but popularly cultivated. The research was conducted in Bonin near Koszalin (north-western Poland) in 2010–2013. Tuber infection was assessed using DAS ELISA in a grow-out test in the winter-spring period. Among the 19 cultivars examined, eight had high resistance to PVY (above grade 8 on a scale of 1–9); during the 3-year research period, they were not infected. Also, cv. Gawin seemed more resistant than previously assumed. In contrast, cvs. Hermes and Sylvana, which were rated in the Netherlands as quite resistant, were clearly very susceptible (grade 3–4) in Polish conditions, as within 2 years 100% of tubers were infected with this virus. The greatest susceptibility to PVM was shown by cvs. Danuta and Stasia, 50% of which were infected, despite moderate exposure to the virus. Cultivars Zenia, Etiuda, Jubilat, and Viviana appeared very resistant to PVM as the number of infected tubers did not exceed 5%. PVM was not detected in the tubers of cvs. Bursztyn, Gustaw, and Legenda, which confirmed that these cultivars possess the Rm gene. Not all cultivars regarded susceptible (grade 3–4) to PLRV were infected. The virus was not found in tubers of cv. Bursztyn, while in cv. Hermes, assessed in the Netherlands as being quite resistant, almost 40% of tubers were infected.  相似文献   

8.
Potato Virus Y (PVY) is one of the most devastating pathogens threatening potato production worldwide. It is a RNA virus that is disseminated by aphids in a non-persistent manner. Regular application of mineral oil on potato fields is known to reduce the number of PVY-positive tubers in post-harvest testing. The mechanism of this phenomenon is not well understood, but it is hypothesized to influence the virus-vector-plant relationships. Here, we present data from greenhouse and field trials that shed light on the effect of mineral oil on local and systemic accumulation of PVYO in susceptible Shepody and Russet Burbank. The data suggests that mineral oil did not influence PVYO levels in mechanically-inoculated leaves nor tubers of plants with a secondary infection. However, a reduction in systemic PVYO levels was observed in mineral oil-treated older plants but not in younger plants, suggesting that mineral oil inhibits PVYO movement in an age-dependent manner.  相似文献   

9.
Currently in vitro plantlets and microtubers provide the basis for pre-base production of potato seeds, from which minitubers are produced under covers – they serve later as seed material to be planted in the field. The aim of the research was to determine the possibility for multiplication of material produced in vitro directly in field conditions. The research assessed PVY, PVM and PLRV infection of potato tubers derived from plants grown directly from in vitro plantlets, microtubers, minitubers and traditional seed potatoes planted in the field at different times. Moreover, testing in laboratory conditions, the susceptibility of these plants to virus infection was determined for the case of artificial inoculation of Myzus persicae and Aphis nasturtii. It was found that the infection of tubers derived from in vitro plantlets and microtubers was greater than that of seed potatoes and minitubers. Yet it seems that the reason for their higher infection level resulted not from the plant’s sensitivity or its greater attractiveness to aphids but from a largely unknown cause. Earlier planting of microtubers and in vitro plantlets in the field in case of the more resistant cultivar and certainly later in relation to the main time of planting had an impact on limiting the PVY and PVM infection of potato tubers. Hence multiplication of microtubers and in vitro plantlets in field conditions could be very economical using cultivars which are relatively resistant to viruses. However, adopting a later than usual planting period (end of June) and applying an additional protective cover (such as non-woven agricultural fabric) in the first period of a plant’s growth, promotes multiplication of microtubers and in vitro plantlets in field conditions for cultivars with low resistance levels.  相似文献   

10.
Studies on the etiology of tuber necrotic ringspot disease in potato   总被引：5，自引：0，他引：5  
Summary Potato virus M (PVM), potato virus S (PVS), potato virus X and tobacco veinal necrosis strain of potato virus Y (PVYR) were isolated from potatoes showing tuber necrotic ringspot disease (TNRD). Potato mop-top virus, tobacco rattle virus, tobacco necrosis virus and tomato black ring virus could not be isolated from the diseased plants. Because PVM and PVS could be isolated from potato plants that did not show symptoms, these viruses could not be causally related to TNRD. However, TNRD is closely connected with infections by PVYR which always could be isolated from potato plants with TNRD symptoms.
Zusammenfassung Aus Kartoffelpflanzen (Solanum tuberosum, Sorten Adema, Malacsinka, Mona Lisa, Romano und Rosalie) die Symptome des Tuber necrotic ringspot zeigten, wurden Kartoffel-M-Virus (PVM), Kartoffel-S-Virus (PVS), Kartoffel-X-Virus (PVX) und Kartoffel-Y-Virus (PVY) isoliert. Die Viren wurden mit Hilfe von Differentialwirten, Elektronenmikroskopie, Serologie und Pr?munit?tstests identifiziert. Die untersuchten Kartoffelknollen zeigten deutlich sichtbar nekrotische Ringsymptome (Abb. 1). Von den Nekrosen aufweisenden Knollen und von Kartoffelpflanzen konnten von allen Sorten drei Viren (PVM, PVS, PVY) isoliert werden, von der Sorte Malacsinka zus?tzlich noch PVX (Tab. 2). Entsprechend den Symptomen der Testpflanzen (Tab. 3) identifizierten wir die Virus-isolate aus Kartoffelpflanzen die Symptome des Tuber necrotic ringspot aufwiesen als PVM, PVS, PVX und PVY. Aus keiner kranken Pflanze konnte Kartoffelbüscheltrieb-Virus, Tabakmauche-Virus, Tabaknekrose-Virus und Tomatenschwarzring-Virus isoliert werden. Da PVM und PVS aus Pflanzen, die keine Symptome aufwiesen, isoliert werden k?nnten, k?nnen diese beiden Viren nicht urs?chlich mit den Symptomen der Tuber necrotic ringspot Krankheit (TNRD) verbunden sein. Wir konnten jedoch eine enge Verbindung zwischen TNRD und der Infektion mit PVY feststellen, da dieses Virus von allen Pflanzen, die Symptome des TNRD aufwiesen, isoliert werden konnte. Die Eigenschaften von PVY-Isolaten aus Knollen, Bl?ttern und Wurzeln ?hnelten jenen, die in verschiedenen Testpflanzen gefunden wurden (Tab. 4). Die typischen Symptomreaktionen aufNicotiana debneyi (Abb. 2) undN. tabacum Sorte Xanthi-nc sowie aufSolanum demissum A6-Hybride lassen vermuten, dass die Ursache ein Tobacco veinal necrosis—Stamm des PVY, (PVYR, siehe Abb. 3) war. Es ist schwierig zu einem endgültigen Ergebnis über die ?tiologie der TNRD zu kommen, weil einige PVYR-isolate sogar aus symptomlosen Kartoffelknollen gewonnen werden konnten. Die Untersuchungen werden fortgesetzt.
Résumé Les virus M (PVM), S (PVS), X (PVX) et Y (PVY) sont isolés à partir de plantes de pommes de terre (Solanum tuberosum cvs Adema, Malacsinka, Mona Lisa, Romano et Rosalie) présentant des sympt?mes de taches nécrotiques annulaires. Les virus sont identifiés à l'aide d'h?tes différentiels, de la microscopie électronique, de la sérologie et de tests de protection croisée. Les tubercules examinés présentent des taches nettement visibles de nécroses annulaires (fig. 1). A partir des tubercules nécrosés et des plantes, trois virus (PVM, PVS, et PVY) sont isolés pour tous les cultivars à l'exception de cv. Malacsinka pour lequel PVX est également isolé (tabl. 2). Les sympt?mes révélés sur les plantes tests (tabl. 3) indiquent que les virus isolés à partir des plantes présentant des sympt?mes de nécroses annulaires sur tubercules sont PVM, PVS, PVX et PVY. Les virus du Mop-Top de la pomme de terre, du rattle du tabac, de la nécrose du tabac et des taches noires en anneau de la tomate n'ont pu être isolés d'aucune des plantes malades. Puisque PVM et PVS peuvent être isolés de plantes de pommes de terre ne présentant pas de sympt?mes, ces deux virus ne peuvent être directement responsables des sympt?mes de taches nécrotiques annulaires sur tubercules (TNRD). Cependant, une relation étroite entre TNRD et la contamination par PVY est établie, puisque ce virus peut être isolé de toutes les plantes présentant des sympt?mes de TNRD. Le tableau 4 regroupe les caractéristiques de quel-ques cultures pures de PVY isolées à partir de tubercules, feuilles et racines et semblables à celles trouvées dans différentes plantes h?tes. Les sympt?mes typiques surNicotiana debneyi (fig. 2) etN. tabacum cv. Xanthi-nc, ainsi que surSolanum demissum-A6-hybride laissent à penser que l'agent responsable est une souche nécrotique des nervures du tabac de PVY (PVYR, voir fig. 3). Il est difficile de conclure de fa?on définitive, quant à l'étiologie de la maladie des taches nécrotiques annulaires, car PVYR peut être également isolé de tubercules ne présentant aucun sympt?me. Des études axées sur l'étiologie de TNRD sont en cours.
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11.
The potato plantlets singly infected by PVA, PLRV, PVS, PVX and PVY and mix-infected by PVM, PVS and PVY were cultured on MS medium with different concentration of ribavirin. The effects of ribavirin on growth of the plantlets and efficiency of virus elimination were investigated. Results showed that the plant height and fresh weight obviously decreased with increase of ribavirin concentration from 0 mg/L to 150 mg/L, and most of the plantlets could not survive when the concentration reached 200 mg/L. According to the ELISA tests, ribavirin was more efficient for eradicating PVA, PVM, PVS and PVX than PVY and PLRV, and healthy plantlets could be obtained with high frequency (up to 100 %) by culturing with 75?~?150 mg/L ribavirin after 2?~?3 subcultures. Whereas, only 33?~?66 % PVY and PLRV infected plantlets were found to be virus-free after 3 subcultures with 75?~?150 mg/L ribavirin. The results of quantitative RT-PCR (qPCR) indicated that ribavirin could obviously reduce virus content in the plantlets. Except PLRV was detected positive after 3 subcultures with ribavirin, the healthy seedlings were obtained from infected stocks at the first or end of propagation and no viruses could be detected at the post-eradication stage. No apparent difference of genetic variation resulted from ribavirin treatment was found by SSR analysis between the control and the treated plantlets. All of these results above proved that ribavirin treatment in vitro was an effective method to eliminate viruses in the propagation of potato.  相似文献   

12.
Potato virus Y (PVY) infection is one of the greatest challenges to seed potato production in the United States. To determine how cultivar and seed type affect the development of systemic PVY infection, Russet Burbank and Russet Norkotah Colorado 3 cultivars were grown from two types of pre-nuclear seed (i.e., plantlets and minitubers) and Generation 3 (G3) tubers and challenged with PVY strain Wilga (PVYN-Wi). Systemic PVY infection was measured by assaying spread of virus from the inoculation site to upper non-inoculated leaves. The Burbank cultivar had a lower incidence of systemic PVY infection compared to the incidence of systemic PVY that developed in the Colorado 3 cultivar. Furthermore, Burbank plants grown from G3 tubers had a lower incidence of systemic PVY infection, as compared to Burbank plants grown from plantlets. Together our results indicate that both cultivar and seed type affect the development of systemic PVYN-Wi infections post-inoculation.  相似文献   

13.
通过采集标样,分离得到头叶线虫,并对此线虫进行培养,获得大批量线虫,作为供试线虫,在室内对几种不同类型杀虫剂进行毒力测定。结果表明:50%辛硫磷乳油、40%氧乐果乳油、50%对硫磷乳油、40.7%乐斯本乳油对头叶线虫具有一定的杀线虫活性,好于其它药剂,同时指出评价一种药剂杀线虫能力的高低还应进行田间试验。  相似文献   

14.
细菌性萎蔫病是世界范围内木薯种植中的重要病害，但防控技术研究较少。采用含毒介质法评价了3种常用杀菌剂对不同来源的29个病菌菌株的抑菌作用。结果表明，供试菌株对净刹(80%乙蒜素EC)和农用硫酸链霉素(72%硫酸链霉素SP)敏感性较高，而对可杀得贰仟(53.8%氢氧化铜WG)表现出不同程度的抗性。建议生产中使用乙蒜素和硫酸链霉素对该病进行防治。  相似文献   

15.
Research plots were established in 1996 and 1997 at Klamath Falls and Hermiston, Oregon and Tulelake, California to determine: 1) the extent of seedborne PVY spread during the growing season; 2) effects of seedborne PVY on yield and grade of Russet Norkotah; and 3) the economic consequences of varying levels of seedborne PVY infections. A series of 5 treatments evaluated initial PVY infection levels of 1 to 60% in 1996 and 1 to 98% in 1997. Virus spread occurred earlier and was more extensive at Hermiston than at Klamath Falls or Tulelake. Plants derived from PVY-free seed were nearly 100% PVY infected at early senescence at Hermiston. Comparisons of potatoes grown from PVY-free seed versus potatoes grown from seed where initial PVY infection levels were 60% in 1996 and 100% in 1997 showed seedborne PVY infection at these levels reduced U.S. No. 1 yields by an average of 40% at Hermiston, 20% at Tulelake, and 12% at Klamath Falls. Predicted total yield losses were 0.19, 0.12, and 0.08 Mg ha?1 for each percent of PVY infection at HAREC, IREC, and KES, respectively. Reductions in gross crop value were estimated at 39, 26, and 14%, respectively, based on regression analyses.  相似文献   

16.
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17.
Potato plays an important role in food security in Kenya but yields are low (<10 t/ha), and this is partly attributed to the lack of healthy planting material. This study is the first wide-scale survey to determine the occurrence and distribution of common potato pests and diseases in Kenyan seed (certified and quality declared) and ware crops. Potato crops growing on 101 farms in 21 districts were examined. Approximately 36% of plants in farmers’ fields sampled both during the long rains (main potato-growing season) and short rains seasons displayed virus-like disease symptoms. Six viruses (potato leafroll virus (PLRV), Potato virus A (PVA), potato virus M (PVM), potato virus S (PVS), potato virus X (PVX), and potato virus Y (PVY)) were detected using double antibody sandwich enzyme-linked immunosorbent assay in potato samples. Sequencing of polymerase chain reaction products from PVY-infected plants revealed the presence of recombinant strains of PVY (NTN and Wilga). Four aphid species, Macrosiphum euphorbiae, Aphis gossypii, Myzus persicae, and Aphis fabae, colonized potato in all districts, occurring in greater numbers west of the Great Rift Valley than to the east. There was a positive correlation between virus incidence and aphid numbers in the long rains (main) potato-growing season. PLRV, PVM, PVS, PVX, and PVY were detected in solanaceous weeds. Ralstonia solanacearum was detected in soils from 13 farms in 8 of the 18 districts surveyed. Approximately 38% of soil samples were infested with Meloidogyne spp. Phytophthora infestans isolates belonging to the US 1 and 2_A1 genotypes were identified. Although many economically important diseases are present in Kenya, the lower aphid incidence in districts east of the Great Rift Valley may indicate that these districts are more suitable for seed potato production.  相似文献   

18.
The aim of the research was to identify alternatives to chlorpyrifos for the control of light brown apple moth, Epiphyas postvittana, on nursery and ornamental plants. Viburnum tinus L., a commonly grown nursery plant, were infested with E. postvittana eggs, sprayed to run-off and mortality recorded. Several treatments were identified as equally efficacious as the standard chlorpyrifos spray (500 μg/l). The insecticides that compared most favorably with chlorpyrifos were λ-cyhalothrin and γ-cyhalothrin. Four horticultural mineral oils demonstrated good ovicidal properties when evaluated alone versus when combined with reduced rates of the above insecticides or spinosad, imidacloprid or thiacloprid. The response of some insecticide and horticultural mineral oil combinations varied, suggesting that the oil selected may be important. Chlorpyrifos, λ-cyhalothrin, γ-cyhalothrin and spinosad provided similarly high levels of residual control of neonates for up to 10 d from application. Mixtures of UltraPure, an nC21 horticultural mineral oil, with reduced rates of the above insecticides maintained residual efficacy. Alternative treatments evaluated in this study may provide a high level of E. postvittana control through egg mortality and residual effects on emerging neonates over the hatching period. Field trials are required to verify the potential of these alternatives for commercial application.  相似文献   

19.
In 1979 and 1980 field tests were made at Fredericton, New Brunswick to evaluate the effect of various oil application methods on the spread of potato virus Y (PVY) and the phytotoxicity they might cause. Control of PVY by oil sprays reached 64%. Control of spread depended largely on the concentration of the oil, and to a lesser extent, on its delivery rate. Tests did not show any significant effect of the spray pressure. There was no significant difference between eight commercial oil formulations. No significant foliar phytotoxicity or yield reduction resulted from applications of oil, except when a combination of high oil concentration (3% water emulsion) and high rate of application (2240 L/ha) was used. Fungicides mixed with oil or applied immediately after oil produced foliar phytotoxicity. Less phytotoxicity occurred when they were applied 24 h later than oil.  相似文献   

20.
Summary A6 plants were not susceptible to cucumber mild mosaic virus, pea early browning virus and potato mop-top virus. They produced local and systemic symptoms after inoculation with potato virus A (3 isolates), potato virus Y, potato virus X (4 isolates), potato aucuba mosaic virus (1 isolate), tobacco ringspot virus, tomato spotted wilt virus, cucumber mosaic virus (1 isolate) and only local necrotic symptoms after inoculation with potato virus A (2 isolates), tobacco mosaic virus, tobacco necrosis virus, tobacco rattle virus (3 isolates), tobacco etch virus and tomato black ring virus.A6 plants became systemically infected without symptoms after inoculation with potato aucuba mosaic virus (5 isolates), potato virus S, potato virus M and potato virus X (1 isolate). Detached leaves of those plants could be used reliably for the detection of potato virus A and potato virus Y.
Zusammenfassung Es wurde festgestellt (K?hler, 1953; de Bokx, 1964; Spire et al., 1969), dass auch andere Viren als PVA und PVYA6 infizieren k?nnen. Eine unbekannte Infektion vonA6 k?nnte die Ergebnisse des für die Untersuchung auf PVA und PVY verwendetenA6-Testes beeinflussen. Aus diesem Grunde wurden gesundeA6-Pflanzen mit 20 Viren (und deren Isolaten) inokuliert, um herauszufinden, ob sie gepflückte oder nicht gepflückte Bl?tter vonA6-Pflanzen infizieren und Symptome ausl?sen k?nnen (Tabelle 1). Ferner wurde geprüft ob infizierte, symptomloseA6-Bl?tter für die Routine-Untersuchungen auf PVA und PVY verwendet werden k?nnen. Gepflückte Bl?tter vonA6-Pflanzen, die in einem blattlausfreien Glashaus gezogen wurden, undA6-Pflanzen, die in Klimakammern (20°C; Beleuchtung w?hrend 13 Stunden/Tag, Licht-intensit?t 16.000 lx) aufwuchsen, wurden nach Verletzung durch Karborundpulver 500 Mesh mit zerquetschten, virushaltigen Bl?ttern inokuliert. Das Vorkommen eines Virus sowohl in inokulierten als auch in nicht inokulierten Bl?ttern vonA6-Pflanzen wurde serologisch oder mit Testpflanzen untersucht (Tabelle 1). A6-Pflanzen waren nicht anf?llig für das Pea early browning-Virus, das Kartoffel Mop-top-Virus und das milde Gurkenmosaikvirus InA6 wurden generell lokale Infektionen verursacht durch CMV, PVA, TEV, TMV, TNV, TRV und TBRV (Tabelle 2; Abb. 1, 2, 3, 4, 5, 6, 7 und 8). Eine lokale und systemische Reaktion inA6 erfolgte nach Inokulation mit PAMV, PVX, PVY und TRSV (Tabelle 3, Abb. 9, 10). A6-Pflanzen wurden symptomlos, systemisch infiziert nach Inokulation mit den Isolaten von PVS und PVM.A6, inokuliert mit einem starken Stamm des AMV, zeigte systemische gelbe Flecken.A6-Pflanzen, systemisch infiziert mit AMV, PMV, PVS oder PVX, k?nnen als Testpflanzen für PVA und PVY (Abb. 11) verwendet werden; es ist aber zu empfehlen, nur gesundeA6-Pflanzen zu benützen, da infizierteA6-Pflanzen als Virusquelle wirken k?nnen. Die Ergebnisse sind in Tabelle 4 zusammengefasst.
Résumé On a observé (K?hler, 1953; de Bokx, 1964; Spire et al., 1969) que d'autres virus que PVA et PVY pouvaient infecterA6. Une infection ignorée pourrait donc fausser les résultats du testA6 utilisé pour la détection de PVA et PVY. On a inoculé 20 virus (et leurs isolats) à des plantesA6 saines pour voir s'ils pouvaient infecter des feuilles détachées et non détachées de plantesA6 et induire des sympt?ms (Tableau 1). On a également recherché si des feuillesA6 infectées mais ne montrant pas de sympt?me pouvaient être utilisées dans les détections en série de PVA et PVY. On a inoculé avec du feuillage broyé porteur de virus, après poudrage avec de la poudre de carborundum de grosseur 500, des feuilles détachées de plantesA6 poussées en serre à l'abri d'aphides ainsi que des plantesA6 développées en chambre climatisée (20°C, éclairage durant 13 h par jour et intensité lumineuse de 16.000 lx).On a examiné sérologiquement et par plantes-tests (Tableau 1) la présence d'un virus à la fois sur feuilles inoculées et non inoculées de plantesA6. Les plantesA6 ne se sont pas montrées susceptibles au virus du brunissement précoce du pois, au virus mop-top de la pomme de terre, et au virus de la mosa?que légère de concombre. Généralement une infection locale surA6 est causée par CMV, PVA, TEV, TMV, TNV, TRV et TBRV (Tableau 2, Fig. 1–8). Une infection locale et systémique surA6 a suivi l'inoculation avec PAMV, PVX, PVY et TRSV (Tableau 3, Fig. 9, 10); l'inoculation des isolats PVS et PVM a provoqué une infection systémique sans sympt?me. L'inoculation d'un strain sévère de AMV a développé des taches jaunes systémiques. Les plantesA6 atteintes d'une infection systémique avec AMV, PVM, FVS et PVX peuvent être utilisées comme plantes-tests pour PVA et PVY (Fig. 11); il est toutefois recommandé de ne cultiver que desA6 sains, étant donné que lesA6 infectés pourraient agir comme source de virus. Les résultats sont résumés dans le Tableau 4.
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