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1.
Potato cyst nematodes (Globodera spp.) are present in most potato-growing areas of the EPPO region. Populations in infested fields are rather easily suppressed by crop rotation. Thus, further spread of these nematodes can be prevented by a national control campaign that prohibits the cultivation of potato on infested plots until the population has been shown by a standard soil test to have declined to a non-detectable level. Alternatively, resistant potato cultivars may be grown, or early ware potatoes which are harvested before cysts mature, or the soil may be disinfested (ware potatoes only). Such rules are widely applied in European countries, but have been successful only in containing the pest (the infested area has not declined). There is now discussion on the application of more stringent measures for seed potatoes, and less stringent (or even deregulation) for ware potatoes. The Globodera spp. might accordingly be treated as regulated non-quarantine pests.  相似文献   

2.
In the northeastern part of the Netherlands starch potatoes are grown intensively. From 392 fields in that area, soil samples that contained the potato cyst nematodeGlobodera pallida were used to analyze the resistance of 7 varieties of starch potatoes.Differences and similarities in resistance of the varieties to the field populations ofG. pallida could well be explained by their descent from distinct sources of resistance.TheG. pallida-populations that showed a relatively high virulence to the varieties Producent, Elles, and Darwina were not equally distributed over the area, but were confined to a small number of regions.  相似文献   

3.
The root lesion nematode Pratylenchus penetrans parasitizes a wide range of economically important crops, including potato (Solanum tuberosum). Damage by P. penetrans impacts not only the potato yield but can also reduce the tuber quality. Detailed information on tuber infection by P. penetrans is scarce for most cultivars and molecular detection of nematodes from infected tubers is needed. The objective of this study was to assess tuber symptomatology due to P. penetrans infection in 10 potato cultivars and to provide an accurate molecular methodology for nematode detection using tuber peels. Sprouts of certified potato seed from cultivars Agata, Agria, Camel, Désirée, Dirosso, Kennebec, Laura, Picasso, Royata, and Stemster were planted in 2 L pots, and soil was inoculated with 4 P. penetrans/g of soil. Sixty days after inoculation, tubers were harvested, inspected for lesions, and the number of nematodes/g of potato peel assessed. Observations of tubers with symptoms showed the presence of P. penetrans in superficial layers of peels around the lenticels and injured necrotic tissue. Different nematode stages were detected in tubers of all inoculated cultivars, varying from 4 to 46 nematodes/g of potato peel. Species-specific primers showed suitable sensitivity and reproducibility for the detection of P. penetrans in tuber potato peel samples. The molecular detection of P. penetrans directly from tuber peels can facilitate routine nematode inspections of potato seed tubers or cull potatoes for nematode detection, and prevent further dissemination of this species.  相似文献   

4.
PCR-based methods were developed for the detection and quantification of the potato pathogen Spongospora subterranea f. sp. subterranea (S. subterranea) in peel, tuber washings and soil. A partial sequence was obtained for S. subterranea ribosomal DNA and specific PCR primers (Sps1 and Sps2) were chosen from the internal transcribed spacer regions. These primers amplified a 391bp product from S. subterranea DNA but did not amplify DNA from potato or a range of soil-borne microbes, including related species. Diluted S. subterranea DNA was detected at a concentration equivalent to 25×10–5 cystosori or 1 zoospore per PCR. Amplification was detected from peel and washings of infected and apparently healthy tubers, but not from peel of Scottish classified seed potatoes or axenically micropropagated potatoes. A rapid method for extracting S. subterranea DNA from soils was developed. This yielded DNA pure enough for PCR within 3h and facilitated the detection of 1–5 cystosori per gram of soil. A PCR quantification technique was developed involving comparison of product ratios obtained after co-amplification of S. subterranea DNA along with an internal standard (competitor DNA fragment). This quantitative technique was also adapted for use in soil. PCR detection of S. subterranea in soil was considerably more sensitive than previously reported immunoassays and was quicker and easier than conventional bait plant bioassays. Such an assay could be useful for developing disease risk assessments for field soils and seed potato stocks and for future studies on the ecology and control of S. subterranea.  相似文献   

5.
Only two plant parasitic nematode species have practical importance in potato crops in Poland. They are Ditylenchus destructor and Globodera rostochiensis pathotype Ro1. Control of D. destructor is done permanently by the elimination of infested seed potatoes and sowing of cereals in the infested fields. Damage to potatoes is observed rather seldom. G. rostochiensis is widely distributed throughout Poland. It is controlled by non-host crops and by resistant potato cultivars. Chemical control of potato nematodes is not put into practice in Poland.  相似文献   

6.
This study provided information on periods of peak trapping for the potato tubermoth (Phthorimaea operculella) in potato fields and in storage facilities in the Niayes area of Senegal. Delta sticky traps baited with P. operculella synthetic pheromone, IT053 ISCA lure, were used to monitor adult male moth populations in 2011 and 2012. In each trapping year, four peaks were observed with the maximum number of moths recorded in February, 2012. A Weibull regression model was developed to predict the incidence of P. operculella in potato fields using the number of male adults caught in pheromone-baited traps. The Weibull model provided a good fit to percentage cumulative mean trap catches for both 2011 and 2012 (R2 = 0.99; P < 0.0001). Based on the Weibull models for the sampling periods in 2011 and 2012, 50% of cumulative mean number of moths were trapped by day 85 (26 March) in both years, 63.2% (= α) were trapped by day 103 and 104 (13 April and 14 April), and 95% were trapped by day 179 and 190 (28 June and 9 July), respectively. Male moths continued to be trapped after potatoes were harvested, but the numbers decreased compared to captures before harvest. This information will be useful for predicting the most appropriate times to institute intervention measures to mitigate damage to potatoes by the moth. Laboratory investigation revealed that abandoned tubers in the field were the source of sustained incidence of the moth on farms following the harvesting of potatoes. The number of male moths trapped in stores tapered with the number of weeks the bagged tubers stayed in storage.  相似文献   

7.
J. KUCZYNSKA 《EPPO Bulletin》1998,28(4):545-549
Changes in the production of Polish seed potatoes of cultivars that are resistant to potato cyst nematodes have been followed. Over the period from 1972 to 1998, 35 cultivars resistant to Globodera rostochiensis (pathotype RO1) were introduced. Among them, one (Drop) was also resistant to Globodera pallida (PA3) and a number had multiple resistance to diseases and nematodes. Planting of seed potatoes of these resistant cultivars concerned only 0.4% of the total potato area. Against a background of much reduced seed-potato production, the area planted with resistant cultivars fell by 47% over the years 1989/1997). However, the share of resistant cultivars in the total seed-potato area increased from 16% in 1989 to 47% in 1997, the most important cultivars being Lawina, Orlik, Ibis and Irga. In 1992/1993, resistant cultivars occupied only 6–8% of the total potato area.  相似文献   

8.
To determine whether populations of Phytophthora infestans attacking wild and cultivated potatoes in the highlands of Peru are specialized on their hosts of origin, we characterized isolates using several neutral markers, metalaxyl resistance and for aggressiveness in a detached leaf assay. One hundred and fifty-three isolates were collected from the northern and central highlands of Peru from different potato cultivars (both modern and native cultivars) and from different species of wild, tuber-bearing potatoes. All the isolates analyzed belonged to one of four clonal lineages that had been described previously in Peru: EC-1, US-1, PE-3 and PE-7. The EC-1 lineage (n = 133) was dominant and present in similar frequencies on wild and cultivated potatoes. PE-3 (n = 14) was found primarily on cultivated potatoes, with only one isolate coming from a wild host. US-1 (n = 2) and PE-7 (n = 4) were rare; all but one (PE-7) occurred on wild potatoes. Isolates from the EC-1 lineage from modern cultivars were compared in three separate detached leaf inoculation assays with EC-1 isolates from the wild potato species S. sogarandinum, S. bill-hookerii or S. huancabambense, respectively. No significant interactions between isolate type (from wild or cultivated potato) and host type (wild or cultivated) were measured for any assay. It appears that the pathogen genotypes in the EC-1 lineage indiscriminately attack both wild and cultivated tuber-bearing solanaceous hosts in Peru, and breeders should be able to select for resistance using the common EC-1 lineage.  相似文献   

9.
The potential of Biological Soil Disinfestation (BSD) to control potato brown rot, caused by Ralstonia solanacearum race 3 biovar 2, was investigated. BSD involves the induction of anaerobic soil conditions by increasing microbial respiration through incorporation of fresh organic amendments (here: grass or potato haulms) and by reducing re-supply of oxygen by covering with airtight plastic sheets. Control treatments were left without cover and amendment, or amended without covering or covered only without amendment. The effect of BSD on survival of R. solanacearum was tested at three different scales: in 1-l glass mesocosms under laboratory conditions, in 1.2-m-diam microplots positioned in an outdoor quarantine field, and in a naturally infested commercial field. Within a few days, anaerobic conditions developed in the BSD-treated soils. In the mesocosm and microplot experiment, anaerobic conditions persisted till the end of the 4-week experimental period. In the field experiment, the period of anaerobiosis was shorter due to birds damaging the plastic cover. In all three experiments, BSD reduced soil populations of R. solanacearum significantly by 92.5% to >99.9% compared to the non-amended and uncovered control treatments. In the field experiment, BSD also resulted in a significant reduction of R. solanacearum survival in potato tubers buried at 15 or 35 cm and in the rapid decomposition of superficially buried potatoes remaining after harvesting, thus destroying an important inoculum reservoir of R. solanacearum. The treatments with grass amendment only or covering with only plastic did not result in anaerobic conditions and did not decrease R. solanacearum populations during the experimental period. PCR-DGGE analyses of 16S-rDNA from soil samples of the various treatments in the mesocosm and microplot experiments revealed that BSD hardly affected bacterial diversity but did result in clear shifts in the composition of the bacterial community. The possible implications of these shifts are discussed. It is concluded that BSD has the potential to strongly decrease soil infestation levels of R. solanacearum and to become an important element in a sustainable and effective management strategy for potato brown rot, especially in areas where the disease is endemic.  相似文献   

10.
Although Synchytrium endobioticum has been found in almost all potato-growing countries of the EPPO region, it is absent from the great majority of fields. A few plots scattered across the potato-growing areas have been ‘scheduled’ as infested but potatoes are not grown on them. The disease is accordingly hardly ever seen. This is the result of continent-wide multiyear campaign of potato wart control within countries, according to which it is prohibited to grow potatoes on infested plots, and only resistant cultivars may be grown in a safety zone around them. S. endobioticum can persist for several decades in soil, as resting spores, but it is now dying out in plots that have been subject to the control campaign for a sufficiently long period. Procedures are now being agreed for officially ‘descheduling’ such plots.  相似文献   

11.
A method is described for the gas chromatographic determination of residues of isofenphos (BAY 92114, O-ethyl O-2-isopropoxycarbonylphenyl isopropylphosphor-amidothioate) and its phosphoramidate which is a potential metabolite. When potato, cabbage, rapeseed and a sandy loam soil were fortified with 0.01, 0.1 and 1.0 mg/kg and analysed by the method described, the recoveries ranged from 76 to 98%. The limits of detection of the method were 0.5 and 1.0 ng for isofenphos and isofenphos oxygen analogue respectively. Degradation under field conditions of isofenphos to its oxygen analogue was demonstrated in a sample of field-treated potatoes.  相似文献   

12.
ABSTRACT A computer program, SAMPLE, was developed to evaluate existing and create new sampling methods for the detection of infestation foci of the potato cyst nematode (Globodera rostochiensis and G. pallida). By combining a model for the medium-scale distribution of cysts that provides the expected population densities at each position within the focus and a model for the small-scale distribution within square meters, sampling procedures can be simulated. The importance of the parameters of the two distribution models-the length and width gradient for the medium-scale distribution and the aggregation factor k of the negative binomial distribution for the small-scale distribution-was investigated by sensitivity analysis. Parameter k proved to be less important when calculating the average detection probability of a focus than were the length and width gradient parameters. Several existing versions of the statutory sampling method used in the Netherlands were tested for their performance on a standard infestation focus with a central population density of 50 cysts per kg of soil, which is small enough to use resistant potato cultivars as a control measure without noticeable yield reductions in a 1:3 year cropping frequency with potato. These methods did not perform with the desired average detection probability, set at 90%; therefore, SAMPLE was used to develop several new sampling methods for focus detection. SAMPLE is a tool to develop sampling methods on demand for every possible combination of characteristics required for use by seed and ware potato growers (recommendations for optimum control measures leading to maximum returns and integrated pest management) and by governments (legislation, quarantine, and export protection).  相似文献   

13.
The endoparasitic nematophagous fungusHirsutella rhossiliensis was tested for its ability to suppress root penetration and cyst formation by the potato cyst nematode speciesGlobodera pallida. Isolates ofH. rhossiliensis were obtained from infected potato cyst nematode juveniles from different starch potato fields in The Netherlands. The isolates showed no difference in spore adhesion to juveniles on agar plates (adhesion rate: ±90%). The most rapid growing isolate, CBS 108.94, was used for experiments. Vegetative mycelial colonies ofH. rhossiliensis CBS 108.94, grown in potato dextrose broth, were used as soil inoculum. During submerged cultivation the mycelial colonies produced phialides (spore-bearing cells) but no spores. Exposed to the air, however, spores were rapidly formed. The effect of different soil inoculum densities of mycelial colonies on root penetration byGlobodera pallida was examined in an experiment in 250-ml pots. Up to a mycelial colony concentration representing a potential spore density of 104 g–1 soil no suppression occurred. At approximated densities of 2.5×104 and 105 spores g–1 soil the numbers of juveniles which penetrated roots were reduced by 30% and 34%, respectively. The distribution of the inoculum could be improved by fragmentation of the mycelial colonies before soil inoculation. Using mycelial fragments, again no suppression of root penetration was observed up to a potential spore density of 104 g–1 soil, but at densities of 105 and 106 g–1 a suppression of 54% and 88%, respectively, was measured. In a greenhouse experiment, soil inoculation with mycelial colonies with a potential spore production of 2.5×105 g–1 soil resulted in a suppression of root penetration of 37% and 51% after 5 and 6 weeks, respectively, but the number of newly formed cysts after 18 weeks in soil was not different for control and inoculated pots. It is concluded thatH. rhossiliensis may be useful for the reduction of root damage caused by juveniles of potato cyst nematodes, but the usefulness for population control is doubtful.  相似文献   

14.
为探明不同作物与娃娃菜轮作后的效果，在宁夏南部山区进行定位试验，采用高通量测序技术，结合土壤理化性质及酶活性，比较分析了娃娃菜-西兰花(CMB)、娃娃菜-大葱(CMG)、娃娃菜-洋葱(CMO)、娃娃菜-土豆(CMP)和以娃娃菜连作(CCC)为对照的5个处理的微生物多样性，旨在筛选出适宜与娃娃菜轮作的作物，为从栽培模式选择角度缓解或避免娃娃菜连作障碍提供理论依据。试验结果表明：与连作相比，轮作马铃薯土壤硝态氮含量最高为12.8 mg·kg-1,轮作大葱土壤速效磷含量最高为75.74 mg·kg-1,但不同轮作模式下速效钾和有机质含量有所下降。轮作马铃薯土壤的碱性磷酸酶、蔗糖酶与轮作洋葱土壤的过氧化氢酶、脲酶显著低于娃娃菜连作和轮作其他作物。细菌丰度在属水平上的结果表明轮作导致大部分有益细菌属丰度升高，如贪铜菌属(Cupriavidus)、鞘脂单胞菌属(Sphingomonas)、柄杆菌属(Caulobacter)等，有害菌及其他部分未分类功能作用菌属丰度降低，如伯克氏菌(Burkholderiaceae)、黄杆菌属(Flavobacterium...  相似文献   

15.
This paper describes a comparison study of test methods and supports the use of real‐time polymerase chain reaction (PCR) for the detection of Clavibacter michiganensis subsp. sepedonicus and Ralstonia solanacearum in potato tubers in routine testing. These 2 bacteria are quarantine organisms under European Union (EU) regulatory control and testing for (latent) infections of these bacteria in seed potatoes is mandatory. Real‐time PCR tests were performed on 276 routine potato tuber samples, including samples infected with either C. michiganensis subsp. sepedonicus or R. solanacearum, and the performance of these real‐time PCR tests was compared with that of immunofluorescence (IF). Real‐time PCR tests, using different primer sets and extraction and PCR protocols, proved to be sensitive and specific for the detection of C. michiganensis subsp. sepedonicus and R. solanacearum in potato tubers in routine testing, and performed at least as well as IF. Real‐time PCR is a good addition to the detection protocols as laid down in EU regulations (EU Council Directives 2006/56/EC and 2006/63/EC).  相似文献   

16.
Epitrix tuberis and E. cucumeris are major pests of potatoes in North America. E. tuberis causes the most serious damage because the larval feeding can cause superficial serpentine tunnelling on the surface of tubers as well as deeper pits. This damage can make crops unmarketable. By contrast, E. cucumeris mainly damages the foliage, and yield losses can occur when the adults reach high densities. In 2004, potato tuber damage characteristic of E. tuberis was seen in Portugal. In 2008, damage was more widespread and severe. E. cucumeris and a lesser known species, E. similaris, were recorded in affected fields. E. similaris has since been found across Galicia, Spain. E. similaris is thought to be the most likely cause of the tuber damage in Portugal, but it is possible that E. cucumeris or an as yet undetected Epitrix species is causing the damage. In 2010, a pest risk assessment for the Euro‐Mediterranean area identified the movement of adults and pupae with seed or ware potatoes and associated soil as being the highest‐risk pathways for the spread of Epitrix. In 2012, EU emergency measures were agreed to reduce the risk of further introductions and the rate of spread of these pests.  相似文献   

17.
Suspected Dickeya sp. strains were obtained from potato plants and tubers collected from commercial plots. The disease was observed on crops of various cultivars grown from seed tubers imported from the Netherlands during the spring seasons of 2004–2006, with disease incidence of 2–30% (10% in average). In addition to typical wilting symptoms on the foliage, in cases of severe infection, progeny tubers were rotten in the soil. Six strains were characterised by biochemical, serological and PCR-amplification. All tests verified the strains as Dickeya sp. The rep-PCR and the biochemical assays showed that the strains isolated from blackleg diseased plants in Israel were very similar, if not identical to strains isolated from Dutch seed potatoes, suggesting that the infection in Israel originated from the Dutch seed. The strains were distantly related to D. dianthicola strains, typically found in potatoes in Western Europe, and were similar to biovar 3 D. dadanti or D. zeae. This is the first time that the presence of biovar 3 strains in potato in the Netherlands is described. One of the strains was used for pathogenicity assays on potato cvs Nicola and Mondial. Symptoms appeared 2 to 3 days after stem inoculation, and 7 to 10 days after soil inoculation. The control plants treated with water, or plants inoculated with Pectobacterium carotovorum, did not develop any symptoms with either method of inoculation. The identity of Dickeya sp. and P. carotovorum re-isolated from inoculated plants was confirmed by PCR and ELISA.  相似文献   

18.
In the past, the Ukrainian Plant Quarantine Research Institute used to produce true-to-type virus-free potato cultivars by in vitro propagation for its research on pathotypes of Synchytrium endobioticum and Globodera spp. Use of virus-free seed potatoes has considerably declined in the 1990s as potato production has passed almost entirely into private hands. The Institute now has a role to fill in supplying virus-free seed potatoes to local growers and has greatly increased its production in consequence. The techniques used for seed-potato production in Bukovina are described.  相似文献   

19.
Pectobacterium brasiliense (Pbr) infects a wide range of crops worldwide, causing potato blackleg and soft rot and vegetable soft rots. This study aimed to characterize the genetic diversity and virulence variability among 68 Pbr strains isolated from either symptomless potato progeny tubers, diseased potato plants, ware potatoes wash water, or vegetables grown in Israel, as well as strains isolated from symptomless seed tubers grown in Europe, or diseased potato plants grown in France. The collection was typed using PCR and TaqMan real-time PCR analyses, dnaX sequence analysis, pulsed-field gel electrophoresis (PFGE), and pectolytic activity. dnaX phylogeny grouped almost all strains in a common genetic clade related to Pbr, which was distinct from the other Pectobacterium species. PFGE analysis identified two main clusters, including one major group of 47 strains with 95%–100% similarity. Maceration assays on two potato cultivars showed significant differences between strains but with no correlations with the source of the strains nor the status of the host (with/without symptoms). Molecular (dnaX sequences and PFGE profiles) and phenotypic analyses (tuber maceration tests) showed that the tested Pbr strains are not a homogeneous group. Analysis of the tested Pbr strains isolated from potato and vegetables grown in fields with a history of potato cultivation suggests that seed tubers imported from Europe may be the main source for Pbr in Israel. To the best of our knowledge, this is the first study that describes biodiversity and population structure of P. brasiliense isolated from potato and vegetables under hot climate conditions.  相似文献   

20.
Synchytrium endobioticum is one of the most important pathogens of potato and is known for its persistent propagation structures. Under favourable conditions, infection of highly susceptible potato cultivars leads to clearly visible cauliflower‐like tissue warts, the typical symptom of potato wart disease. However, unfavourable infection conditions or low infection pressure may result in symptoms being overlooked. Thus, the introduction of pathogen structures into stages of the processing industry cannot be ruled out. As the amounts of processed potato products continue to rise, phytosanitary risks from processing discarded potatoes and potato waste in biogas plants have to be considered. Hence, the resilience of resting spores against mesophilic anaerobic digestion was analysed in stirred tank reactors. Laboratory‐scale results show that S. endobioticum not only withstands mesophilic anaerobic digestion but also subsequent storage of the digestate for at least 4 weeks. Large numbers of viable resting spores were detectable by microscopic assessment in all samples. Viability was proved and verified additionally by bioassay. Consequently, potatoes, potato waste and processing water from potato processing industries used in biogas plants pose a phytosanitary risk if the accruing digestates are returned as fertilizer to arable land.  相似文献   

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