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1.
N. GRECO  M. DI VITO 《EPPO Bulletin》1994,24(2):393-398
Several endoparasitic nematodes have been reported on leguminous plants in the Mediterranean area. The most widespread are the root-lesion nematodes Pratylenchus mediterraneus, P. penetrans and P. thornei. Symptoms induced by these nematodes usually are not very impressive, but 50% yield loss of chickpea may occur. Among root-knot nematodes, Meloidogyne artiellia is associated with severe yield losses of chickpea in Italy, Spain and especially Syria. Tolerance limits of 0.14 and 0.02 of this nematode per ml soil are reported for winter and spring-sown chickpea, respectively. Meloidogyne incognita and M. javanica can be noxious to French bean and cowpea in sandy soil. The cyst nematode Heterodera goettingiana reduces yields of pea, broad bean and vetch when its population densities exceed 0.5, 1, and 2.1 eggs per g of soil, respectively. Heterodera ciceri occurs in northern Syria and Turkey and is responsible for economic yield losses of chickpea and lentil in fields infested with more than 1 or 2.5 eggs per g of soil, respectively. Pea and grass pea also suffer from infestation of this nematode. The stem and bulb nematode Ditylenchus dipsaci causes severe decline of broad bean, pea and probably lentil during wet seasons. Other nematodes, although present in moderate numbers, appear to have little importance.  相似文献   

2.
A system to grow tomato plants infected by Meloidogyne javanica under constant temperatures of 18, 21, 24, 27 and 30 °C was developed and used to assess how temperature and the application of the biological control bacterium Pasteuria penetrans affected plant growth, the nematode population and endospore production. Each plant was inoculated with 300 second‐stage juveniles (J2) with four or five spores of P. penetrans attached to their cuticles or with 300 nematodes without P. penetrans. Increasing soil temperature increased tomato growth, the number of endospores per female, and the number of galls of M. javanica at the end of 38 days. Increasing temperatures up to 27 °C also increased the number of egg masses produced by M. javanica. Presence of P. penetrans reduced the numbers of galls and egg masses at all temperatures by up to 52.2% and 61.4% at 27 and 30 °C, respectively. Pasteuria penetrans reduced the M. javanica population even at soil temperatures of 18 and 21 °C. However, temperatures of 27 and 30 °C enhanced nematode control and the production of P. penetrans endospores is faster. The system developed in this work is simple and efficient for growing plants under constant temperatures and can be used for different purposes.  相似文献   

3.
Initial applications of 104 spores g−1 of Pasteuria penetrans, and dried neem cake and leaves at 3 and 2% w:w, respectively, were applied to soil in pots. Juveniles of Meloidogyne javanica were added immediately to the pots (500, 5,000 or 10,000) before planting 6-week-old tomato seedlings. The tomatoes were sampled after 64 days; subsequently a second crop was grown for 59 days and a third crop for 67 days without further applications of P. penetrans and neem. There was significantly less root-galling in the P. penetrans combined with neem cake treatment at the end of the third crop and this treatment also had the greatest effect on the growth of the tomato plants. At the end of the third crop, 30% of the females were infected with P. penetrans in those treatments where spores had been applied at the start of the experiment. The effects of neem leaves and neem cake on the nematode population did not persist through the crop sequences but the potential for combining the amendments with a biological control agent such as P. penetrans is worthy of further evaluation.  相似文献   

4.
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   

5.
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6.
Plant parasitic nematodes belonging to the genus Pratylenchus, also known as root lesion nematodes, cause serious economic damage to different crop plants. In order to explore genetic structures in different isolates, we investigated several P. thornei, P. neglectus and P. penetrans populations of different geographic origins. The analysis at the species level was also extended to P. penetrans, P. pinguicaudatus, P. vulnus and P. mediterraneus. Sequence analysis of a specific portion of DNA was carried out. In particular, the sequences of the D3 region of the 26S gene were obtained and compared with similar sequences available in databases. The results support the hypothesis that P. penetrans may represent a species complex, while in P. neglectus the intra-species heterogeneity observed is due to intra-individual variability. Furthermore, the specific conservation of some nucleotides in different P. thornei populations indicates their fixation in the rDNA repeats in this species. The presence of these nucleotides, the molecular signature of P. thornei, may assist in determining the nature of nematode infections.  相似文献   

7.
Root-lesion nematodes of the genus Pratylenchus are migratory endoparasites with worldwide economic impact on several important crops including potato, where certain species like P. penetrans, P. neglectus, and P. scribneri reduce the yield and quality of potato tubers. Morphological identification of Pratylenchus spp. is challenging, and recent advancements in molecular techniques provide robust and rapid diagnostics to differentiate species without the need of specialist skills. However, the fact that molecular diagnostics are not available for all Pratylenchus species means that there are limitations in worldwide application. In general, root-lesion nematodes are difficult to manage once introduced into agricultural land and damage can be related to pathogenicity and population densities. In addition, root-lesion nematodes interact with fungi such as Verticillium dahliae, resulting in disease complexes that enhance the damage inflicted on the potato crop. Management interventions are often focused on limiting nematode reproduction before planting crops and include the application of nematicides, and cultural practices such as crop rotation, cover crops, biofumigation, and biological control. Understanding the limitations of the available crop protection strategies is important and there are many gaps for further study. This review discusses the status of the diagnosis, distribution, pathogenicity, and management of the main species of root-lesion nematodes, reported to infect potatoes worldwide, and highlights areas for potential future research.  相似文献   

8.
Commercial vineyards in southern Spain were surveyed and sampled during October to December 2004 to determine the extent to which common weeds present were suitable hosts of root-knot nematodes infesting soils of those vineyards. Seven weed species commonly growing in grapevine soils in southern Spain were found infected by either Meloidogyne incognita or M. javanica: Amaranthus retroflexus (redroot pigweed), Anchusa azurea (ox-tongue), Chenopodium album (goosefoot), Erodium moschatum (musk stork’s bill), Malva rotundifolia (low mallow), Sinapis alba (white mustard), and Solanum nigrum (black nightshade). The host suitability of the weeds to root-knot nematodes was evaluated on the basis of root galling severity and nematode population densities in soil and roots. Also, the host–parasite relationship in these naturally Meloidogyne-infected weeds was examined. All the weed species in the study were considered suitable hosts for M. incognita and M. javanica because: (a) high Meloidogyne spp. populations occurred in roots and surrounding soil of the weed species; (b) the severity of root galling was high, and (c) well-established permanent feeding sites were observed in the histopathological studies of infected root tissues. In addition, this study presents the first reports of S. alba and A. azurea as hosts for M. incognita, and of E. moschatum as a new host for M. javanica, thus increasing the list of reported weed hosts for Meloidogyne spp. These results indicate that noticeable population densities of M. incognita and M. javanica can be maintained or increased in these weeds, at population levels higher than those previously reported for the same nematodes infecting grapevine roots. The weeds infesting vineyards thus represent an important source of inoculum of Meloidogyne spp., and furthermore may act as reservoirs of these nematodes which can be disseminated within or among vineyards by agricultural operations.  相似文献   

9.
Pratylenchus penetrans is one of the most economically damaging plant-parasitic nematodes and is found on a wide variety of crops. Correct identification and quantification of this nematode are necessary for providing advice to farmers, but are not easily obtained with the traditional way of microscopic observation. We developed a qPCR assay to detect and quantify P. penetrans in a short but accurate manner. A qPCR primer set, including two primers and a TaqMan probe, was designed based on the sequence of the β-1,4-endoglucanase gene. The assay was optimized by using the primers in a qPCR assay with SYBR green I dye and setting the qPCR program to different annealing temperatures ranging from 60 °C to 64 °C. Based on the Ct-values, we retained the program with an annealing temperature of 63 °C. The assay with the probe was very sensitive as it was able to detect a single individual of P. penetrans, even when mixed with up to 80 individuals of P. thornei. The specificity of the reaction was confirmed by the lack of amplification of DNA from 28 populations of 18 other Pratylenchus species and from plant-parasitic nematodes from nine other genera. DNA from 21 different isolates from P. penetrans was amplified. DNA extraction from 80 individuals and quantification by qPCR was repeated four times; Ct-values showed consistent results (Ct?=?24.4?±?0.4). A dilution series from DNA of P. penetrans resulted in a standard curve showing a highly significant linearity between the Ct-values and the dilution rates (R2?=?0.99; slope?=??3.23; E?=?104 %). The tests showed a high correlation between the real numbers of nematodes and the numbers detected by the qPCR. The developed qPCR assay provides a sensitive means for the rapid detection and reliable quantification of individuals of this pest. This method does not require expertise in nematode taxonomy and morphology, and can be used as a rapid diagnostic tool in research, as well as in diagnostic labs and extension services advising farmers for pest management.  相似文献   

10.
Cs. BUDAI 《EPPO Bulletin》1994,24(2):511-514
Under Hungarian climatic conditions, root-knot nematodes, and other phytoparasitic nematodes, generally cause damage in certain plant growing areas. These pests are present in glasshouses throughout the country. In the field the nematodes occur in sandy soil in the vegetable-growing areas of southern and central Hungary. The following species of root-knot nematodes have so far been reported to occur in Hungary: Meloidogyne incognita, M. arenaria, M. hapla, M. javanica, M. incognita acrita, M. thamesi and M. naasi. There are 10 specific nematicides registered for nematode control in the country. These chemicals are mainly applied in glasshouses where their use produces most economic return. Nematoderesistant cultivars are only available in the case of tomato. The nematodes cause the heaviest damage on glasshouse cucumber.  相似文献   

11.

Root-knot nematodes cause substantial economic loss of yield in coffee plantations and vegetable crops in Cuba. At present, methods to control the nematodes are ineffective or inappropriate and alternatives are being sought. The nematophagous fungus Verticillium chlamydosporium (Goddard) was isolated from soils collected from coffee plantations and infected root-knot nematode eggs from roots of tomato plants grown in these soils. A total of 83 isolates were collected and identified morphologically as V. chlamydosporium var. chlamydosporium, V. chlamydosporium var. catenulatum, V. psalliotae, V. suchlasporium and an isolate of V. chlamydosporium var. chlamydosporium with unusually large dictyochlamydospores. From these, 24 that represented a range of origins were selected and screened for their ability to parasitize eggs of root-knot nematodes, colonize the rhizosphere of barley roots and produce chlamydospores. None of the isolates grew at temperatures below 15°C and V. suchlasporium grew at a faster rate at lower temperatures than the other isolates. These were also screened in the glasshouse and V. chlamydosporium var. catenulatum caused the greatest reduction in nematode populations. One isolate of each subspecies of V. chlamydosporium was tested with the standard, Rothamsted isolate 10, on a range of host plants. The greatest reduction in numbers of nematodes occurred on tomato plants (cv. Pixie). The Rothamsted isolate 10 reduced numbers of nematodes toa greater extent than the other isolates, and therefore has the greatest potential as a biological control agent of root-knot nematodes.  相似文献   

12.
Summary Raspberries and strawbereis planted several years after a previous crop of raspberries were found attacked byPratylenchus penetrans. Raspberries planted in places where appled trees had been taken out showed slightly stunted growth and a moderate attack of the roots byP. penetrans.The symptoms of heavily infested raspberries were: severely stunted growth of above ground parts without other particular symptoms; a very poor root system, parts of which are completely dead and blackened or show dead, blackened bark, and the absence of fine feeding roots. In cases of light attack the root system is more normal but there is a number of rather large black lesions.Raspberries should not be planted after raspberries, after fruit trees susceptible to attack byP. penetrans, after strawberries or on possibly infested soil (in general light soils) unless a determination of the degree of infestation in the plant sites has shown that the place is safe. In case of infestation suitable measures to eradicate the nematodes should be taken. It may be expected that a fairly light degree of infestation of the soil is sufficient to cause appreciable damage.  相似文献   

13.
Investigations on the efficacy of various methods of managing root-knot nematodes in microplots and under field conditions revealed that soil solarization, Furadan 5G and Tagetes erecta applied separately or in combination with other control methods, were the most effective in reducing the numbers of three root-knot nematodes, and root gall and egg mass indices. These management methods also resulted in significant increases (P0.05) in number of pods per plant, number of seeds per pod and 100-seed weight, and increased seed yield by up to 96.7 percent. Farmyard manure and Crotalaria ochroleuca were the least effective treatments. The use of T. erecta was the most economical root-knot nematode control method.  相似文献   

14.
棉隆与淡紫拟青霉联合防治番茄根结线虫病的效果评价   总被引：4，自引：0，他引：4  
为明确土壤熏蒸与生防微生物对番茄根结线虫病的联合作用效果,采用移栽前棉隆熏蒸处理后穴施淡紫拟青霉Paecilomyces lilacinus YES-2-14生防菌剂的方法在温室大棚开展了联合防治试验。结果表明,棉隆用量为35 g/m~2时,24周拉秧时线虫数量减少90%以上,防效达到85.5%;移栽时穴施浓度10~7~10~8CFU/g的淡紫拟青霉菌剂,24周拉秧时防效为44.4%~59.6%;而当线虫初始密度达到674头/100 g土时,单一菌剂防效只有12.5%,但番茄长势和产量显著提高。棉隆熏蒸后再联合施用淡紫拟青霉菌剂,2个月和5个月时防效比单一棉隆处理分别提高14.1%和21.8%,比单一菌剂处理提高14.3倍和4.1倍,产量较对照、棉隆熏蒸和单一菌剂处理分别提高22.1%、9.5%和2.4%,且该处理地块线虫数量始终最低,与对照差异显著,而淡紫拟青霉数量则高于单一淡紫拟青霉菌剂处理。表明棉隆和淡紫拟青霉菌剂联合使用不仅能显著降低线虫数量,有效防治番茄根结线虫病,还能够促进植株生长并提高产量。  相似文献   

15.
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16.
宁夏葡萄苗圃根结线虫病发病症状、为害程度及种类   总被引：2，自引：0，他引：2  
为有效防治葡萄苗圃根结线虫病,采用拔根百分法和直接解剖法调查宁夏永宁县玉泉营镇葡萄苗圃葡萄苗木根结线虫病的发病症状、为害程度,并通过形态学和分子生物学对其种类进行鉴定。结果表明:15个葡萄品种的病害症状之间有一定差异。除抗砧3号外,其余14个葡萄品种均受根结线虫侵染,且不同葡萄品种受根结线虫为害的严重度差异明显,其中西拉、红芭拉蒂、爱神玫瑰、阳光玫瑰、马瑟兰、贝达和黑比诺上根结线虫病较严重,病情指数介于51.67～78.33之间,大青的病情指数最低,为21.67。不同葡萄品种的每根段雌成虫数量之间、每根段根结数量之间差异明显,其中葡萄品种贝达的每根段雌成虫数量和每根段根结数量最多,分别为12.47条和4.27个,葡萄品种黑比诺的每根段雌成虫数量和每根段根结数量较少,分别为3.60条和1.73个;每根段雌成虫数量随着每根段根结数量的增加而增加。根据根结线虫2龄幼虫、雌成虫和会阴花纹的形态学特征及分子生物学鉴定结果确定为害葡萄苗圃的根结线虫主要为南方根结线虫Meloidogyne incognita和花生根结线虫M. arenaria。除抗砧3号外,其它14个葡萄品种均不同程度的感染了南方根结线虫和花生根结线虫,且所有葡萄品种感染南方根结线虫的比例均较高。  相似文献   

17.
Damage caused by nematodes is one of the limiting factors in crop production. Traditional nematode management is based on the use of crop rotations, resistant cultivars, nematicides, or combinations of these methods. For a crop like peanut (Arachis hypogaea), cultivars resistant to root-knot nematodes are not available. There are soybean (Glycine max) cultivars resistant to some of the species of root-knot nematodes (Meloidogyne spp.); however, most fields have nematode infestations composed of mixtures of species. Research at Auburn has shown that tropical crops can be used effectively in rotation to manage nematode problems. Rotations with American jointvetch (Aeschynomene americana), castor (Ricinus communis), hairy indigo (Indigofera hirsuta), partridge pea (Cassia fasciculata), sesame (Sesamum indicum), and velvetbean (Mucuna deeringiana) have resulted in good nematode control and increased yields of peanut and soybean. Some crops (castor, sesame) are considered ‘active’ in that they produce compounds that are nematicidal, whereas others (e.g. corn, sorghum) are simply non-host, that is, ‘passive’.  相似文献   

18.
Plant-parasitic nematodes pose a major threat to crop production in Nigeria. Comprehensive data on yield losses for most cereal crops are not readily available. Research on maize (Zea mays), rice (Oryza sativa), and sorghum (Sorghum bicolor) has shown an 18%–67% reduction in yield linked to the destructiveness of parasitic nematodes, particularly root-knot and root-lesion nematodes. Continuous monoculture and a conservative approach to agriculture increase the incidence and population density of nematodes, leading to higher levels of damage and losses in most cultivated cereal crops. These losses affect the food security of the growing population of Nigeria and many African countries that are heavily dependent on cereals. The accurate identification of nematodes is fundamental for effective management strategies. Nematode taxonomy based on morphology has been difficult due to intraspecific character variations coupled with the limited expertise of indigenous nematologists. Biochemical and molecular marker-based tools and approaches have allowed efficient diagnosis of most nematode species affecting cereal production globally. These approaches have proved useful due to their practicality, rapidness, accuracy, and cost-effectiveness. This review describes the important economic effects of these parasitic nematodes on cereal production and highlights the need for integrative approaches to taxonomy for accurate species identification that will improve nematode diagnosis, thereby contributing to the increase of food production in Nigeria.  相似文献   

19.
Two major proteins, Mcf-A67 and Mcf-B66, were identified by mini two-dimensional polyacrylamide gel electrophoresis in order to distinguish the two European quarantine root-knot nematodes, Meloidogyne chitwoodi and M. fallax, from eight other species. These quarantine proteinic markers have been microsequenced after enzymatic digestion. The internal amino acid sequences exhibit similarities to members of a family of low molecular weight intracellular lipid-binding proteins. Moreover, to explore a simple, rapid, and inexpensive way to identify the two quarantine nematodes, dot blot hybridizations were performed using an antiserum (A67) produced from the longest amino-acid sequence of the protein Mcf-A67. Although several proteins stained on the M. chitwoodi and M. fallax western blot membranes, the two nematodes were easily distinguished from other root-knot nematodes, on dot blot assays with soluble proteins extracted from a single female. Because of its specificity and sensitivity, the use of the A67 antiserum to improve the diagnosis of the two European quarantine root-knot nematodes is discussed.  相似文献   

20.
Since weeds serve as hosts for nematode pests, the host status of 20 weed species (commonly occurring in fields of developing farmers) to Meloidogyne incognita and M. javanica, respectively, were investigated. Greenhouse studies showed that seven weed species had Rf values >1 for both nematode species indicating susceptibility, while 13 had Rf values ≤ 1 indicating resistance. Greenhouse results showed that Hibiscus trionum and Amaranthus tricolor were identified as the most susceptible and Chenopodium carinatum and Datura ferox the poorest hosts for M. incognita and M. javanica. For field experiments at Kuruman, Solanum retroflexum was the most susceptible weed to a M. javanica population, while the same was evident for H. trionum at Nelspruit, where a mixed population of M. incognita and M. javanica occurred and at Potchefstroom, where a population of M. incognita was present. Results from this study indicated that certain weed species are highly susceptible to root-knot nematodes and should be removed timely and effectively to prevent population level increases of root-knot nematode pests in the fields of farmers.  相似文献   

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