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1.
The host suitability of commercial Vitis rootstocks commonly used in Spain (161‐49C, 41B, 1103P, 110R, 140Ru and SO4) to root‐knot nematodes (Meloidogyne arenaria, M. incognita, M. javanica) and Xiphinema index, and damage caused by nematode infection were determined under controlled conditions. The three root‐knot nematodes reproduced with a rate higher than one in all rootstocks, indicating that they are suitable hosts for these nematodes. Growth of rootstocks infected with the root‐knot nematodes was less vigorous than that of nematode‐uninfected controls in the majority of the rootstocks studied. Root infection resulted in moderate to severe root galling in all rootstocks. The shoot and main stem diameters appeared to be the most sensitive variables of damage caused by infection by Meloidogyne spp., with reduction rates from 36% and 53% in 161‐49C to 57% and 66% in 140Ru, respectively. The shoot height was not significantly affected by the root‐knot nematodes and the root fresh weight generally increased as a consequence of intensive galling. The nematode X. index caused significant root damage with a reproduction factor higher than one in all rootstocks. However, reproduction factor was significantly influenced by the rootstock and significantly decreased by about 12‐fold (5·7 to 18·1‐fold) with the increase in inoculum density from 100 to 1000 nematodes per plant. The root dry weight was reduced by X. index infections, and was the plant growth variable most affected by the nematode infection in all rootstocks at both inoculum densities. Meloidogyne arenaria, M. incognita, M. javanica and X. index, prevalent in many world vineyards, are all shown to have a damaging effect on the six tested rootstocks.  相似文献   

2.
BACKGROUND: The small number of available nematicides and restrictions on the use of non‐fumigant nematicides owing to high toxicity to human and non‐target organisms hinder effective nematode control. The nematicidal efficacy of MCW‐2, a new nematicide of the fluoroalkenyl group, was evaluated against the root‐knot nematode Meloidogyne javanica (Treub.) Chitwood. RESULTS: MCW‐2 showed irreversible nematicidal activity against second‐stage juveniles of M. javanica in vitro, following exposure for 48 h at concentrations as low as 0.5 mg L?1, in contrast to fenamiphos or cadusafos. When exposed to MCW‐2 for shorter periods, motile juveniles became immobile with time after rinsing in water. MCW‐2 at 8 mg L?1 inhibited nematode hatching, which, however, recovered after rinsing in water. In pot and plot experiments, 0.5 mg MCW‐2 L?1 soil and 2 kg MCW‐2 ha?1, respectively, controlled M. javanica similarly to or better than fenamiphos or cadusafos at the same concentrations or at their recommended doses. In the soil, the nematicidal activity of MCW‐2 was less persistent than that of fenamiphos. CONCLUSION: MCW‐2 has potential to be used as a new non‐fumigant nematicide that probably has a novel mode of action. Copyright © 2009 Society of Chemical Industry  相似文献   

3.
The effects of root‐knot nematodes on black root rot of watermelon and bottle gourd were studied using field surveys and co‐inoculation tests with Meloidogyne incognita (southern root‐knot nematode) and Diaporthe sclerotioides. The results of the field survey suggested that root‐knot nematodes had little effect on either the severity of black root rot or infection with D. sclerotioides. None of the three fields showed a significant positive correlation between disease severity and nematode gall index, with low correlation coefficients. Co‐inoculation experiments under controlled conditions found no significant effect of root‐knot nematodes on black root rot of watermelon and bottle gourd based on area under disease progress curves (AUDPC). These results were supported by the quantities of DNA of the two agents in root tissues because no significant difference was found between dual‐ and single‐inoculation treatments with M. incognita and/or D. sclerotioides. These findings suggest that root‐knot nematodes probably do not affect the infection of watermelon or bottle gourd roots by D. sclerotioides or the incidence of black root rot in these crops caused by this fungus.  相似文献   

4.
Benomyl, prochloraz or procymidone, applied as an overall plant spray at the openflower stage, effectively suppressed Botrytis cinerea fruit rot, whereas no control was achieved by foliar application only. Fruit rot was prevented using procymidone applied to the soil 12 days before inoculation of the flowers, whereas benomyl or prochloraz gave little or no control, respectively when applied in the same manner. Bioassays, using Penicillium expansum on leaf and flower extracts of strawberry plants growing in soil treated with procymidone, showed the presence of an inhibitory compound with the same RF value on thin-layer chromatography as that of procymidone. Analysis by gas chromatography and identification by gas chromatography—mass spectrometry established that the fungicide procymidone was translocated from the root system of strawberry plants to the leaves and flowers.  相似文献   

5.
我国烟草根结线虫病发生与防治研究进展   总被引:1,自引:0,他引:1  
 烟草根结线虫病是一种严重影响烟叶产量和质量的重要病害之一。近年来,随着烟叶种植布局的优化调整以及大气温室效应的影响,烟草根结线虫病在全国各烟区的危害逐年加重,因此必须加强对烟草根结线虫病的发生与防治研究。本文详细综述了我国烟草根结线虫病的发生分布、危害损失、致病机制、发病规律及防治措施等研究进展,并对烟草根结线虫的鉴定技术、协同致病、抗病育种以及新型防控技术进行了总结和展望。明确了我国烟草根结线虫病优势种为南方根结线虫,并且多种根结线虫混发的现象逐步增加。同时,发现由烟草根结线虫病诱发的多种其他根茎类病害的危害逐年加重。通过加强烟草根结线虫发生动态监测、合理布局抗病品种、应用针对性的农业防治、生态防治和生物防治等综合防治措施,可以逐步实现对烟草根结线虫病的绿色防控,从而促进烟草产业的健康发展。  相似文献   

6.
Pathogenicity and host‐parasite relationships in root‐knot disease of celery (Apium graveolens ) caused by Meloidogyne incognita race 1 were studied under glasshouse conditions. Naturally and artificially infected celery cv. D’elne plants showed severe yellowing and stunting, with heavily deformed and damaged root systems. Nematode‐induced mature galls were spherical and/or ellipsoidal and commonly contained more than one female, males and egg masses with eggs. Feeding sites were characterized by the development of giant cells that contained granular cytoplasm and many hypertrophied nuclei. The cytoplasm of giant cells was aggregated along their thickened cell walls and consequently the vascular tissues within galls appeared disrupted and disorganized. The relationship between initial nematode population density (Pi) and growth of celery plants was tested in glasshouse experiments with inoculum levels that varied from 0 to 512 eggs and second‐stage juveniles (J2) mL?1 soil. Seinhorst's model y = m + (1 – m)zP–T was fitted to height and top fresh weight data of the inoculated and control plants. The tolerance limit with respect to plant height and fresh top weight of celery to M. incognita race 1 was estimated as 0·15 eggs and J2 mL?1 soil. The minimum relative values (m) for plant height and top fresh weight were 0·37 and 0·35, respectively, at Pi ≥ 16 eggs and J2 mL?1 soil. The maximum nematode reproduction rate (Pf/Pi) was 407·6 at an initial population density (Pi) of 4 eggs and J2 mL?1 soil.  相似文献   

7.
为明确公主岭霉素在草莓生产中的防病诱抗效应,于大田采用五点取样法调查公主岭霉素对草莓白粉病的防控效果及对植株生长性状的影响,并于室内采用生测法测定其对草莓叶片防御酶活性和根际土壤酶活性的影响。结果显示,以公主岭霉素水浸提液100倍稀释液进行灌根并协同叶面喷雾对草莓白粉病的预防效果为71.90%;单独叶面喷雾对草莓白粉病的治疗效果为69.90%;灌根协同叶面喷雾预防与叶面喷雾治疗的综合防控处理对草莓白粉病的防治效果可达85.37%。公主岭霉素水浸提液100倍稀释液灌根后草莓幼苗的株高、叶柄长、叶长、叶宽、叶数、径冠等方面均优于清水对照;叶面喷施可提升叶片中多酚氧化酶和超氧化物歧化酶的活性,喷雾后1 d内即较清水对照显著提高;5 d后过氧化氢酶活性显著高于清水对照。灌根后根际土壤中蔗糖酶的活性在用药后15 d内均显著高于清水对照。表明合理施用公主岭霉素可实现对草莓白粉病的有效防控,并诱导提升草莓植株的抗病性,改善草莓生长环境,促进其生长。  相似文献   

8.
Atmospheric emission of the soil fumigant 1,3‐dichloropropene (1,3‐D) is of environmental concern because of its toxicity and carcinogenicity. Thiosulfate fertilizers have been found to rapidly transform 1,3‐D in soil to non‐volatile ions which are less toxic. We investigated the use of surface application of ammonium thiosulfate (ATS) for reducing 1,3‐D volatilization. In packed soil columns, emission of 1,3‐D applied by sub‐surface injection decreased with increasing ATS application rate and the amount of water used for delivering ATS. When ATS was applied in 9 mm water at 64 g m−2, total 1,3‐D emission was reduced by 61%. The reduction was 89% when ATS was applied at 193 g m−2. Bioassays showed that ATS application did not affect the effectiveness of 1,3‐D for controlling citrus nematodes. In field plots where a 1,3‐D emulsified formulation was applied via sub‐surface drip, surface spray of ATS reduced 1,3‐D emissions by 50%, and by 71% when the surface was also covered with polyethylene film. ATS application had no effect on the efficacy of root‐knot nematode control or tomato yields. These results suggest that surface application of thiosulfate fertilizers may be a feasible and effective strategy for minimizing 1,3‐D emissions. © 2000 Society of Chemical Industry  相似文献   

9.
采用喷雾和灌根两种施药方法,设置高、低两个浓度,测定吡虫啉在草莓植株中的分布及对草莓蚜虫的防效。结果表明,喷雾处理区,草莓叶片中吡虫啉初始沉积量高于茎,叶片中持留的吡虫啉消解较快,而茎中消解较慢;灌根处理区,叶片中吡虫啉积累量于药后7 d达到最大值,之后缓慢减少,茎中吡虫啉持留量在药后1~28 d相对稳定。随着时间推移,不同施药方法对蚜虫的防效不同。喷雾法短期防效(7 d内)优于灌根法,但持效期较短。灌根施药法速效性较差,但持效期长,药后7~28 d防效保持在70%以上。同时,随着施药浓度的增加,灌根法的速效性有良好的提升。  相似文献   

10.
The prevalence and diversity of plant parasitic nematodes in Northern Ireland cereal and grassland was determined from 191 agricultural fields. A total of 18 nematode genera were detected, including economically important pests, Meloidogyne spp., Heterodera spp. and Pratylenchus spp., each of which were above economic damage thresholds in a significant proportion of the sites (92.4%, 70% and 28.6%, respectively). The detection of the root knot nematode, Meloidogyne minor (6% prevalence), was significant given its recent emergence across the turf grass sector and the prospect of M. minor becoming a common agricultural pest. Analyses of nematode prevalence and abundance highlighted significant associations with grass and cereals, soil types, soil grade (proxy for soil quality) and rainfall levels. Specifically, nematode populations varied between the two major soils (brown earths and gleys), while significant trends for increased nematode diversity and greater prevalence of both Meloidogyne and Pratylenchus with increasing rainfall were also observed. Multivariate analyses were performed to determine interactive effects and the relative importance of the factors affecting nematode populations. Notably, rainfall, in combination with either crop type or soil grade, had a significant effect on nematode abundance and diversity. The findings suggest significant changes in nematode populations have occurred over the last several decades and the possibility that these are linked to changing climate and cropping practices are discussed, as well as future concerns for plant parasitic nematode management.  相似文献   

11.
Ochradenus baccatus is a widely distributed shrub in desert regions of the Middle East and North Africa. This plant's nematicidal activity against the root‐knot nematode Meloidogyne javanica was evaluated because it has been found to contain exceptionally high levels of glucosinolates. In in vitro assays with aqueous extracts of the plant, 100% of second‐stage juveniles were immobilized after exposure to 4% root‐core extract for 48 h; 8% root‐core extract suppressed their hatching by 87%, whereas stem, flower and root bark showed lower activity. Incorporation of root core or bark into the soil, as fresh or dry powder at 1 and 0·5% (w/w), respectively, reduced the number of nematodes recovered from the soil by 95–100%, whereas the flower and stem were much less effective. Results from further pot experiments indicated that only the root bark consistently contains nematicidal compounds which are effective in soil, whereas the nematicidal activity of the root core in soil was inconsistent. The presence of non‐volatile lipophilic and lipophobic nematicidal compounds in the root bark was suggested by extraction with different polar solvents, but these compounds do not seem to be isothiocyanates – glucosinolate‐hydrolysed compounds with nematicidal activity. Very poor host status of Ochradenus baccatus to M. javanica, Mincognita and M. hapla, but with root‐penetration rates of juveniles similar to those in tomato roots, suggest that this plant may be used as a cover plant or trap plant to reduce nematode populations in the soil.  相似文献   

12.
膏体迷向剂对苹果园梨小、桃小食心虫的防效   总被引:1,自引:0,他引:1  
2013年在宁夏苹果园进行了复合膏体迷向剂对梨小、桃小食心虫防效的进一步试验,试验设3个处理(涂抹高度3.5m、3.5m/4.5m交叉涂抹、交叉涂抹空白区域)、1个对照,2种膏剂附着方式(树干附着、膏剂填装塑料瓶悬挂)。通过监测全年诱蛾量、调查果实膨大期与成熟期蛀果率分析防控效果。结果显示,复合式膏体迷向剂可有效防止梨小食心虫对果实的为害,涂抹高度3.5m时,梨小食心虫诱蛾量下降76.68%;交叉涂抹时,下降70.8%;交叉涂抹空白区域下降36.8%。3个处理成熟期蛀果率分别下降84.88%、91.39%、24.19%。由于试验区桃小食心虫种群密度小,试验无法确定该迷向剂对桃小食心虫的防治效果。  相似文献   

13.
The application of silicon to the roots or leaves reduces the severity of powdery mildew (Podosphaera xanthii) in melon but the latter treatment is less effective. This study compared key biochemical defence responses of melon triggered by P. xanthii after root or foliar treatment with potassium silicate (PS). Treatments consisted of pathogen‐inoculated or mock‐inoculated plants supplied with PS via roots or foliarly, as well as a non‐treated control. The activity of defence enzymes and the concentration of phenolic compounds, lignin and malondialdehyde were determined from leaf samples at different time points after inoculation. Pathogen‐inoculated plants irrigated with PS showed both an accumulation of silicon and primed defence responses in leaves that were not observed in pathogen‐inoculated plants either sprayed with PS or not treated. These responses included the anticipated activity of peroxidase and accumulation of soluble phenols, the activation of chitinase and repression of catalase, and the stronger activation of superoxide dismutase, peroxidase and β‐1,3‐glucanase. Moreover, the lignin concentration increased in response to inoculation, whereas the malondialdehyde concentration decreased. For the foliar treatment, however, only an increase in lignin deposition was observed compared with the control plants. The results show that silicon strongly plays an active role in modulating the defence responses of melon against P. xanthii when supplied to the roots as opposed to the foliage.  相似文献   

14.
番茄抗性品种与黄瓜轮作对根结线虫的防治作用   总被引:6,自引:0,他引:6       下载免费PDF全文
通过室内盆栽试验探讨对根结线虫具有不同抗性的番茄品种与黄瓜轮作减轻根结线虫病危害的可行性。试验结果表明:抗性品种多菲亚能极大降低土壤中根结线虫2龄幼虫和卵的密度,减轻黄瓜根结线虫病的危害;抗性砧木Beaufort也能显著地降低土中根结线虫和卵的密度,但下茬黄瓜根结线虫的危害与对照相比没有显著差异。表明抗性品种与感病品种轮作能有效地防止根结线虫的发生。  相似文献   

15.
Nematicidal activity of the leaf powder, leaf extracts and formulated leaf extracts of Myrtus communis, an evergreen shrub that is widely distributed in Israel and other Mediterranean countries, was evaluated using the root‐knot nematode Meloidogyne javanica in in vitro and pot experiments. Leaf powder added to sand at 0·1% (w/w) reduced the number of juveniles recovered from the sand by more than 50%. Reduction in galling index and number of nematode eggs on tomato roots was also observed by incorporating the leaf powder at 0·1–0·4% (w/w) in the soil in pot experiments. Leaf powder extracts with methanol or ethanol showed the highest nematicidal activity among all extracts tested. Emulsifiable concentrates of leaf‐paste extract at a concentration as low as 0·005% (a.i., w/w) reduced the number of juveniles recovered from treated sand and the gall index of cucumber seedlings. The extract paste at 26 g m?2 was also effective in reducing the gall index of tomato plants in field‐plot experiments. The leaf powder at 0·2% and the formulated leaf‐paste extract at 0·02% were also nematicidal to Tylenchulus semipenetrans and Ditylenchus dipsaci, but not to Pratylenchus penetrans or Steinernema feltiae. At least three nematicidal compounds were found in the leaf extract upon fractionation by thin‐layer chromatography. The results suggest that the leaf powder and paste extract of M. communis are potential nematicides against root‐knot nematodes.  相似文献   

16.
BACKGROUND: Spray volume can influence the amount of free water on the leaf surface and subsequently the ability of entomopathogenic nematodes (EPNs) to move. In this study, an investigation was made of the effect of spray volume (548, 730 and 1095 L ha−1) on the deposition, viability and infectivity of EPNs against Galleria mellonella on savoy cabbage, cauliflower and leek. RESULTS: Increasing spray volume decreased nematode deposition on 7.1 cm2 leek leaf discs at a 15° angle with the spray nozzle. Although the number of living nematodes observed on leek after 240 min of exposure was not significantly different between the low-volume application (548 L ha−1) and the high-volume application (1095 L ha−1), a greater infectivity was obtained in the latter application. The higher number of droplets deposited on the leek discs in the high-volume application may have stimulated nematode movement. No significant effect of spray volume was observed on the relative deposition of Steinernema carpocapsae on the bottom side of cauliflower and savoy cabbage leaf discs. In spite of the low S. carpocapsae deposition on the bottom side of the savoy cabbage discs, high infectivity was obtained against G. mellonella. Using the lowest spray volume on savoy cabbage, infectivity decreased with increasing exposure time, while infectivity was not affected by exposure time when a spray volume of 730 L ha−1 or more was used. CONCLUSION: Spray volume is an important application parameter, as it affects nematode infectivity. Future research should investigate the effect of spray volume in the field and its influence on the effect of adjuvants. Copyright © 2012 Society of Chemical Industry  相似文献   

17.
Coffea arabica cultivars Catuaí 44 and IAPAR 59, susceptible and resistant, respectively, to the root knot nematode Meloidogyne exigua, were grown in pots containing Si‐deficient soil amended with either calcium silicate (+Si) or calcium carbonate (?Si). There was an increase of 152 and 100%, respectively, in Si content of root tissue of cvs Catuaí 44 and IAPAR 59 in the +Si compared to the ?Si treatment, but no significant difference between Si treatments for calcium content. Plants, assessed 150 days after inoculation (d.a.i.) showed that the number of galls (NG) and number of eggs (NE) significantly decreased by 16·8 and 28·1% respectively, for susceptible cv. Catuaí 44 in the presence of Si, whilst both NG and NE were significantly lower for cv. IAPAR 59 compared to the susceptible cultivar regardless of Si treatments. In a separate experiment, biochemical assays were carried out 5 and 10 d.a.i. There was no significant difference between Si treatments and cultivars for concentration of total soluble phenolics. The concentration of lignin‐thioglycolic acid (LTGA) derivatives significantly increased by 11·5% in roots of nematode‐inoculated plants of susceptible cv. Catuaí supplied with Si. In roots of inoculated plants of resistant cv. IAPAR 59, the increase was 23 and 10%, respectively, for treatments with and without silicon. Peroxidase (POX), polyphenoloxidase (PPO) and phenylalanine ammonia lyase (PAL) activities significantly increased in roots of inoculated plants compared with roots of non‐inoculated plants, regardless of cultivar or Si treatment. In +Si treatments at 10 d.a.i., POX activity in roots of nematode‐inoculated plants of cvs Catuaí 44 and IAPAR 59 increased by 39·9 and 31·3%, respectively; PPO increased by 54·9 and 56·1%; and PAL activity was also higher at 26·6 and 62·9%. It was concluded that supplying Si to coffee plants increases root resistance against M. exigua by decreasing its reproductive capacity.  相似文献   

18.
The reproductive behaviour of the root‐knot nematode Meloidogyne arenaria race 1 was compared on two wild species of Arachis (A. duranensis and A. stenosperma) and cultivated peanut (A. hypogaea cv. IAC‐Tatu‐ST). The three species were considered moderately susceptible, resistant, and susceptible, respectively. Penetration and development of the root‐knot nematode in the resistant species was reduced in comparison with that occurring in susceptible plants. Several cell features, including dark blue cytoplasm and altered organelle structure were observed in the central cylinder of A. stenosperma, indicating a hypersensitive‐like response (HR) of infested host cells. Neither giant cells, nor nematodes developed beyond the second stage, were found on A. stenosperma. Arachis duranensis showed a delay in the development of nematodes in the roots compared to A. hypogaea. The two wild peanut species were chosen to be the contrasting parents of a segregating population for mapping and further investigation of resistance genes.  相似文献   

19.

BACKGROUND

Tuta absoluta (Lepidoptera: Gelechiidae) is difficult to control by means of foliar insecticides, partly because of the endophytic feeding behavior of its larvae. The biopesticide spinosad is applied as a foliar spray for control of T. absoluta and has systemic properties when applied as a soil drench to the growing medium of tomato plants. The aims of this study were to determine the: (i) instar-dependent tolerance of larvae to spinosad; (ii) efficacy of spinosad drench application for the control of larvae; (iii) residual period of systemic activity of spinosad in leaves and fruit after drenching; and (iv) effect of spinosad drenching on tomato plant growth parameters.

RESULTS

The estimated LC50 value (Lethal Concentration at which 50% of the larvae died) differed between instars. The LC50 for second-instar larvae (0.41 ppm) to spinosad was significantly lower than that for third- (0.64 ppm) and fourth-instar (0.63 ppm) larvae. The LC80 value (Concentration at which 80% of the larvae died) for fourth-instar larvae (2.48 ppm) was 2.6- and 1.7-fold higher than that for the second- and third-instar larvae, respectively. The spinosad concentration recorded in leaves at 25 days after treatment (DAT; 0.26 μg g−1) was significantly lower than that in leaves sampled at 3, 10 and 15 DAT. High larval mortalities were, however, recorded for the duration of the experiment, which lasted 25 days (equivalent to one T. absoluta generation).

CONCLUSION

Systemic spinosad effectively controlled T. absoluta larvae over a prolonged period. However, drenching this insecticide violates the recommendation of the Insecticide Resistance Action Committee to avoid treating consecutive insect generations with the same mode of action and can therefore result in the evolution of insecticide resistance. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

20.
BACKGROUND: Considerable attention has been paid to plant‐growth‐promoting rhizobacteria (PGPR), especially the fluorescent group of Pseudomonas species, as the best alternatives to chemicals for facilitating ecofriendly biological control of soil‐ and seedborne microorganisms. On the basis of their novel plant‐growth‐promoting attributes, two rhizobacteria Pseudomonas aeruginosa VP1 and VP2 selected out of over 63 isolates from the rhizosphere of chilli (Capsicum annuum) were identified as potential candidates for biocontrol of the root‐knot nematode Meloidogyne incognita on chilli. RESULTS: The nematicidal activity of both strains was evaluated in vitro and in vivo for their efficacy against M. incognita. P. aeruginosa VP2 exhibited strong nematicidal activity in comparison with VP1, based on the in vitro killing of the second‐stage juveniles (J2) of M. incognita. Seed bacterisation with both strains VP1 and VP2 was able to manage root‐knot M. incognita on chilli (C. annuum) in a pot trial study. Increase in root and shoot length and in fresh and dry weight of root and shoot and reduction in the root‐knot index over the control were attained. In overall performance, VP2 was 29.5% more effective than VP1, and about 30% more effective than the control (non‐bacterised). CONCLUSION: The application of P. aeruginosa VP1 and P. aeruginosa VP2 controls the development of M. incognita in C. annuum, and hence they are recommended as efficient plant growth promotors and biocontrolling agents for raising healthy crop of C. annuum that can promote the growth of plants and reduce the nematode (M. incognita) population. Copyright © 2012 Society of Chemical Industry  相似文献   

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