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Summary Alkaloids and alkaloid-producing plants have the potential to reduce crop damage by plant-parasitic nematodes. In a series of in vitro experiments, the nematicidal activity of the tropane alkaloids, hyoscyamine and scopolamine, and a mixture of both on the root-knot nematode, Meloidogyne incognita, was tested. Solutions of 16 mg of compound per ml of solvent were used in concentrations of 80-1280 μg ml−1 of water. Inactivity of second-stage juveniles of M. incognita increased with increasing concentration and exposure time. Lethal concentrations (LC50) after 120 min of exposure ranged from 182.4 μg ml−1 for scopolamine to 318.4 μg ml−1 for hyoscyamine and 332.8 μg ml−1 for the combination of both alkaloids. Similarly, the same concentrations of scopolamine inhibited hatching of M. incognita to a greater extent than hyoscyamine. In a glasshouse experiment, M. incognita was not able to penetrate the roots, induce galls and reproduce on Datura stramonium, D. innoxia and D. tatula. Results indicate that the tropane alkaloids hyoscyamine and scopolamine contained in Datura plants express a strong nematicidal activity against M. incognita and could possibly be used for an alternative and sustainable nematode management.

Summary The effects of temperature and absence of a host plant on the population dynamics of the sheath nematode, Hemicycliophora conida, were studied under glasshouse conditions. Regarding temperature, population dynamics of H. conida on tomato ‘Moneymaker’ were monitored weekly over a period of 12 weeks. In the first experiment, with an average temperature of 21.4°C, population growth of H. conida continuously increased over time from an initial density of 106 nematodes (100 ml soil)−1 to a final density of 820 nematodes (100 ml soil)−1, resulting in a reproduction rate of 7.7. The time required to complete one generation was 6.5 weeks or 598 temperature degree days at 8°C base temperature (TDD8). A second experiment showed that the development of H. conida on tomato was faster at 22.1°C than at 19.0°C. At 22.1°C, one generation was completed after 6 weeks (= 588 TDD8) compared to 8 weeks (=634 TDD8) at 19.0°C. The higher temperature also resulted in a higher reproduction rate (93 at 22.1°C vs 7.8 at 19.0°C). In the absence of a host plant, the population density of H. conida decreased over time. However, this natural decline was less pronounced than for the root-knot nematode Meloidogyne hapla. In the first experiment, the population density of H. conida decreased within 18 weeks by 89.5%, while M. hapla was already no longer detectable 12 weeks after inoculation. In the second experiment, H. conida decreased by 98.2% within 16 weeks compared to 99.98% for M. hapla.

The present study documents the root-knot nematodes (RKN) fauna of the Poonch division in Azad Jammu and Kashmir infecting vegetables. An overall prevalence of 40% of RKN was recorded. Of the four districts investigated, maximum prevalence was recorded in district Poonch with 59%, followed by Sudhnuti with 58%. The lowest prevalence of RKN was found in districts Bagh (29%) and Haveli (33%). Out of 15 vegetables investigated, RKN was found on five crops. The highest prevalence of 37.8% was recorded on okra, followed by 31.3% on cucumber and 17.5% on tomato. RKN was less prevalent on eggplant (8.3%) and beans (7.7%). Three RKN species, that is Meloidogyne incognita, Meloidogyne javanica and Meloidogyne arenaria, were found infecting the hosts. M. javanica was found to be the most prevalent followed by M. incognita and M. arenaria. This trend was found in all the districts. Overall prevalence of M. javanica as sole population was 9% and that of M. incognita was 2%. Meloidogyne arenaria was not found in any of the fields as sole population. The prevalence of M. incognita with M. javanica or M. arenaria as mixed populations was 8% and 5%, respectively, and that of M. javanica with M. arenaria was 4%. Similarly, all the three species prevailed as mixed populations in 12% of the fields in the division. The severity of RKN infections, measured as galling index, was found to be variable within each infected field (GI 2–9). Identification of RKN species was based on the morphology of perineal patterns and confirmed by molecular SCAR and CO1 makers based identification. In conclusion, RKN were distributed in the Poonch division and M. javanica was predominant. Cucumber, okra, tomato and eggplant were severely attacked by these nematodes warranting the adoption of stringent control strategies for their management.

Nematode-suppressive soils are characterized by the ability of soil microbial communities to reduce populations of plant-parasitic nematodes (PPN) either directly or by inducing systemic resistance in plants. Various microorganisms have been recognized as antagonists of PPN in suppressive soils using culture-dependent and culture-independent methods. However, the associations that PPN form with microorganisms in nematode-conducive soils have been poorly studied. Here we drenched tomato rhizospheres with microbial suspensions from nine different soils and followed their effects on plant growth and root invasion of the infective second-stage juveniles (J2) of the northern root-knot nematode species Meloidogyne hapla. Based on the number of invaded J2, four soils were determined as nematode-suppressive, while five soils were categorized as nematode-conducive. To reveal bacteria attached to the J2 cuticle in soils with varying suppressiveness, we incubated J2 in suspensions from three suppressive and three conducive soils, and analyzed J2-attached bacteria using amplicon sequencing of the V3-V4 region of 16S rRNA gene. Our results suggest that the soil origin had a major effect on the composition of J2-attached bacteria, while the highest bacterial abundance and richness were observed on J2 from two suppressive soils. In addition, the highest number of indicator amplicon sequence variants (ASVs) was associated with J2 in two suppressive soils, but they had a very distinct bacterial profile. Further studies are needed to resolve the complexity of nemato-microbial interactions in soil and to determine the exact function of nematode-attached microorganisms in suppressive and conducive soils and their role in nematode suppression and protection.

Trichodorids may cause both direct damage to the plants as well as indirect damage through transmission of Tobacco rattle virus in potatoes. Trichodorids include nematodes of among others the genera Paratrichodorus and Trichodorus, which are the most common in north-western Europe. This chapter discusses the economic importance, host range, distribution, symptoms of damage, biology and life cycle, interactions with other nematodes and pathogens, recommended integrated management and management optimization of trichodorids. Future research requirements are also mentioned.

Summary The plant-parasitic nematode, Paratylenchus bukowinensis, occurs ubiquitously in arable fields. Economic damage has been reported from, among others, cabbage, parsley, and celery, but other crops might be affected as well. Management of P. bukowinensis is difficult. Resistant cultivars are not available and chemical control is prohibited in most European countries. In addition, sustainable management is often hindered by a lack of information regarding the biology and host range of P. bukowinensis. To improve the management of P. bukowinensis in the future, a good understanding of the life cycle and host plant-nematode interactions is required. We investigated the host range, life cycle and natural decline of P. bukowinensis in five glasshouse experiments. A total of 26 plant genotypes comprising 22 plant species from eight plant families were studied. Plant species within the families Brassicaceae and Apiaceae were confirmed as good hosts, while plant species within the families Fabaceae, Asteraceae, Amaryllidaceae, Solanaceae, Amaranthaceae and Poaceae can be considered non-hosts or poor hosts. In roots of good hosts, P. bukowinensis completed its life cycle within 3-4 weeks. In the absence of a host plant, P. bukowinensis declined by 40% within the first 4 weeks, but then remained at this level until the experiment was terminated after 14 weeks. Overall, the host range of P. bukowinensis seems to be smaller than for other species within the genus Paratylenchus, such as P. projectus or P. similis. Control of P. bukowinensis using crop rotation should be feasible by rotating good hosts belonging to the families Brassicaceae and Apiaceae with non-hosts or poor hosts.

Summary Characterising the non-neutral genetic variation within and among populations of plant-parasitic nematodes is essential to determine factors shaping the population genetic structure. This study describes the genetic variation of the parasitism gene vap1 within and among geographic populations of the beet cyst nematode Heterodera schachtii. Forty populations of H. schachtii were sampled at four spatial scales: 695 km, 49 km, 3.1 km and 0.24 km. DGGE fingerprinting showed significant differences in vap1 patterns among populations. High similarity of vap1 patterns appeared between geographically close populations, and occasionally among distant populations. Analysis of spatially sampled populations within fields revealed an effect of tillage direction on the vap1 similarity for two of four studied fields. Overall, geographic distance and similarity of vap1 patterns of H. schachtii populations were negatively correlated. In conclusion, the population genetic structure was shaped by the interplay between the genetic adaptation and the passive transport of this nematode.

Pratylenchus penetrans is an economically important root-lesion nematode species that affects agronomic and ornamental plants. Understanding its diversity is of paramount importance to develop effective control and management strategies. This study aimed to characterize the morphological and genetic diversity among seven European isolates. An isolate from the USA was included in the molecular analyses for comparative purposes. Morphometrics of the European P. penetrans isolates generally were within the range of the original descriptions for this species. However, multiple morphometric characteristics, including body length, maximum body width, tail length and length of the post-vulval uterine sac showed discrepancies when compared to other populations. Nucleotide sequence-based analyses revealed a high level of intraspecific diversity among the isolates. We observed no correlation between D2-D3 rDNA- and COXI-based phylogenetic similarities and geographic origin. Our phylogenetic analyses including selected GenBank sequences also suggest that the controversy surrounding the distinction between P. penetrans and P. fallax remains.

This chapter discusses the economic importance, geographical distribution, host range, damage symptoms, biology and life cycle, interactions with other nematodes and pathogens, and recommended integrated management of Paratylenchus bukowinensis infesting vegetables. Future research requirements and future developments are also mentioned.

Nematodes can be present in different matrices. This chapter describes several methods to extract nematodes from soil and plant parts. It is crucial that an appropriate method is chosen for the purpose of the research as different types of nematodes, and even different nematode stages, are extracted depending on the method. Factors to consider for choosing the optimal extraction method are the extraction efficiency of the method, the maximum sample size that can be analysed and costs of the extraction equipment. In addition, water consumption, labour and the time needed before nematodes can be examined can be important factors.

Estimating nematode numbers is required to quantify the presence of certain nematode taxa in plant tissue, field soil or any other substrates. This chapter describes the enumeration of nematodes within plant tissue (e.g. roots, stems, leaves, seeds) and in liquids. It also deals with estimating numbers of cysts; eggs and juveniles isolated from cysts; gall index; and egg masses.

Organic farming systems are generally based on intensive soil tillage for seed bed preparation and weed control, which in the long-term often leads to reduced soil fertility. To avoid this, organic farming systems need to adopt conservation agriculture practices, such as minimum tillage and diligent crop rotations. However, minimum tillage generally delays soil warming in spring causing reduced nitrogen mineralization and thus poor plant growth. This negative effect needs to be compensated. We hypothesize that, in a diverse crop rotation, organic minimum tillage based on frequent cover cropping and application of dead mulch will improve soil fertility and thus crop production as confirmed by a number of chemical and biological soil indicators.We made use of two long-term field experiments that compare typical organic plough-based systems (25 cm) with minimum tillage systems (Results from the field experiments showed an increase of macronutrients (+52%), micronutrients (+11%), microbial biomass (+51%), microbial activity (+86%), and bacterivorous nematodes (+112%) in minimum tillage compared with the plough-based system. In the accompanying greenhouse bioassay, pea biomass was 45% higher under minimum than under plough tillage. In conclusion, the study showed that under organic conditions, soil fertility can be improved in minimum tillage systems by intensive cover cropping and application of dead mulch to levels higher than in a plough-based system. Furthermore, the abundance of bacterivorous nematodes can be used as a reliable indicator for the soil fertility status.

Summary Soybean, Glycine max, is a relatively new crop in Europe gaining increasing interest for its potential to fix atmospheric nitrogen and thus increase sustainability of modern agricultural production systems. Under temperate conditions, root-lesion nematodes (Pratylenchus spp.) are one of the most prominent plant-parasitic nematode taxa of economic concern in soybean. Here, we investigated the susceptibility of soybean cultivars towards naturally occurring populations of Pratylenchus spp. and their effects on soybean yield. At the site Bundesallee the cultivars ‘Abelina’, ‘Primus’ and ‘Taifun3’ supported the highest infestation and multiplication of a mixed population of P. neglectus and P. crenatus, while ‘Sultana’ and ‘Solena’ were least susceptible. At the field site Groß Lüsewitz, ‘Primus’ and ‘Merlin’ cultivars were significantly more susceptible to P. neglectus than ‘Sultana’. Soybean yield was reduced by high initial densities of Pratylenchus spp. Results are expected to contribute to a better nematode management.

The nematophagous fungus Hirsutella rhossiliensis is a common antagonist of a number of important plant-parasitic nematodes including the beet cyst nematode Heterodera schachtii. Although H. rhossiliensis is highly pathogenic, slow growth characteristics and weak competiveness under field conditions limit its biocontrol potential. Cellulose-based microcapsules were tested for their ability to improve fungal competitiveness in the soil and nematode parasitism. In a first approach microcapsules containing 15% fungal mycelium plus 15% corn gluten and 0.5% yeast extract as additives gave low levels of H. schachtii control. Fungal parasitism was not observed and indicated that nematode mortality was most likely caused by non-specific accumulation of nematicidal compounds associated with decomposition of the additives in the microcapsules. Removal of the corn gluten additive resulted in a minor increase of 20% parasitism of H. schachtii juveniles. Furthermore, the yeast extract that acted as nutrient source for the fungus diffused through the semi-permeable membrane of the capsules during the formulation process and was ineffective. Replacing the corn gluten and yeast extract with 3% autoclaved baker’s yeast and using finely dispersed mycelium instead of pelletized mycelium increased juvenile parasitism in the soil up to 90% and decreased number of juveniles per cm root length by over 80%. Cellulose-based microcapsules supplemented with autoclaved baker’s yeast, therefore, proved to be an effective delivery system for H. rhossiliensis to control H. schachtii.

Prionchulus sturhani sp. nov. is described and illustrated from Germany. This new species is characterized by medium body length (1.63–1.88 mm), rounded head, cephalic papillae bigger than labial ones, cylindrical and medium sized (35.1–39.7 × 19.2–20.0 μm) buccal cavity, lower position of dorsal tooth (17.6–20.0% of the buccal cavity length), relatively short tail (77.3–87.7 μm, c=20.5–24.4, c'=1.7–2.2) with rounded tip, female genital branches without spermatheca and valvular apparatus between uterus and oviduct, pars refringens vaginae with close and poorly marked, almost transparent, narrow drops-shaped sclerotizations, relatively long and thick walled pars distalis vaginae.

Soybean [Glycine max (L.) Merrill] is the most economically important legume in the world. One of the main yield limiting factors is plant parasitic nematodes, such as Heterodera glycines, Meloidogyne incognita or Pratylenchus brachyurus, which cause severe damage in the main production regions of soybean around the world. For Germany, soybean is still a relatively newly cultivated crop and so far, no information about the occurrence and damage potential of plant parasitic nematodes on soybean is available for this region. For a successful growth of soybean, farmers need to understand, which plant parasitic nematodes can be of risk for soybean production. Within this respect, the objective of this study was to describe the spectrum and abundance of plant parasitic nematodes occurring on soybean under temperate conditions in Germany. Data were collected from farmer fields and experimental sites throughout Germany between 2014 and 2015. Representative soil samples were taken before planting and shortly after harvest. Plant parasitic nematodes were extracted by centrifugal floatation, and identified morphologically to genus level. Selected individuals of Pratylenchus were further identified to species level based on COI gene sequences. The population dynamics of Pratylenchus penetrans and co-occurring plant parasitic nematodes on soybean cv. Merlin was studied in microplots. Finally, the impact of P. penetrans affecting nitrogen fixation by the symbiotic bacterium Bradyrhizobium japonicum was studied in greenhouse experiments. Our findings indicated that Pratylenchus is widely spread in soybean fields in Germany. Main species were P. neglectus and P. crenatus and to a lesser extent P. penetrans. In the microplot experiment, nematode multiplication was highest for P. penetrans, followed by Rotylenchus robustus and Paratylenchus projectus. Infection of soybean by P. penetrans significantly reduced nitrogen fixation as indicated by lower numbers of bacteroids and reduced concentration of ureides In conclusion, Pratylenchus spp. are considered to be the most threatening plant parasitic nematodes for soybean production under the temperate conditions of Germany.

Root-knot nematodes (Meloidogyne spp.) cause extensive damage to tomato and cucurbit crops in protected cultivation systems. An environmentally benign solution for nematode control is the use of plant resistance that mitigates yield losses and reduces the Meloidogyne population in the soil. A collection of three tomato and six cucumber rootstocks was tested for resistance against eight Meloidogyne incognita populations (with different levels of virulence) in comparison with the susceptible variety Moneymaker and the resistant varieties Phantasia or Oskar. In addition, M. enterolobii was included in these experiments to evaluate the response of the tomato and cucumber plant genotypes. Tests were both conducted in a greenhouse or growth chamber and evaluated after completion of one reproduction cycle. The correlation of plant responses to Meloidogyne populations from the different experiments showed significant relationships for 13 and 20 out of 36 combinations for the parameters gall index and number of egg masses per root system, respectively. In particular, two a-virulent reference populations showed significant positive relationships for both parameters, resulting in the same ranking of tested plant genotypes across test systems. Conversely, plant genotypes showed different responses when inoculated with virulent populations of M. incognita or M. enterolobii. Some of the plant genotypes tested showed potential for use in Meloidogyne spp. management strategies. However, cucumber plant genotypes seemed more suitable than tomato genotypes. Furthermore, some of the tested cucumber rootstocks were less sensitive when challenged with M. enterolobii in pot experiments.

The overall goal in nematode management is to develop sustainable systems where nematode populations are kept under the economic damage threshold. Conservation tillage and subsidiary crops, applied as cover crops and living mulches, generally improve soil health by increasing soil organic matter content and stimulating soil microbial activity. However, more permanent crop and weed cover associated with subsidiary crops and noninversion tillage, respectively, may benefit plant-parasitic nematodes with broad host spectra such as Meloidogyne and Pratylenchus. These genera are major constraints to many field crops throughout Europe and there is a need to identify effective and reliable management options that can be applied to avoid excessive infestations. The dynamics of the indigenous fauna of plant-parasitic nematodes were studied in eight coordinated multi-environment field experiments (MEEs) under four agro-environmental conditions in Europe (Continental, Nemoral, Atlantic North and Mediterranean North). The MEEs consisted of a 2-year sequence of wheat combined with a living mulch or subsequent cover crops and second main crops maize, potatoes or tomatoes depending on site. Additionally, the effects of inversion tillage using the plough were compared with various forms of conservation tillage (no-tillage, shallow and deep noninversion tillage). Overall, Helicotylenchus, Paratylenchus, Pratylenchus and Tylenchorhynchus were the most frequent genera across sites while Meloidogyne occurred only in Germany at very low densities. During the wheat–maize sequences in Switzerland, the populations of Pratylenchus increased from 63 to 146 nematodes per 100 mL soil and Helicotylenchus from 233 to 632 nematodes per 100 mL soil. The effects of tillage on plant-parasitic nematodes were generally minor, although no tillage in Italy supported higher densities of Pratylenchus (184 nematodes per 100 mL soil) than inversion tillage (59 nematodes per 100 mL soil). Furthermore, Pratylenchus densities were 160 nematodes per 100 mL soil when leguminous subsidiary crops were grown, 122 nematodes per 100 mL soil in the green fallow and 84 nematodes per 100 mL soil after growing black oat (Avena strigosa) or oilseed radish (Raphanus sativus). The differences were greatest in Italy, in a sandy soil with low organic matter. Application of compost or nitrogen fertiliser had no consistent effects on plant-parasitic nematodes. We conclude that crop rotations including specific subsidiary crops are prominent factors affecting the indigenous nematode community, while tillage and fertiliser are of lower importance.

Summary In certain soils populations of plant-parasitic nematodes (PPN) decline. Understanding this effect may open up environmentally friendly management options. We identified such a suppressive soil containing virtually no PPN. Inoculated Meloidogyne hapla declined in this soil more than in a control soil and reproduction on tomato was reduced. The extracted soil microbiome alone decreased root invasion of second-stage juveniles (J2) and progeny as well as the native soil. We tested the antagonistic potential against PPN that differ in life strategies. The microbiome was most suppressive against two populations of M. hapla and one population of Pratylenchus neglectus, and least suppressive against M. incognita and the ectoparasite Hemicycliophora conida. In a split-root system with M. hapla, plant-mediated but not direct effects of the microbiome significantly reduced root invasion of J2, while direct exposure of M. hapla to the microbiome significantly affected reproduction. Overall, both plant-mediated and direct effects of the microbiome were responsible for the soil suppressiveness against M. hapla.

Early maturing varieties of soybean have a high yield potential in Europe, where the main biotic threat to soybean cultivation are root lesion nematodes (Pratylenchus spp.). Nitrogen fixation in root nodules by highly efficient inoculants of Bradyrhizobium japonicum is an incentive to grow soybean in low-input rotation systems. We investigated density-dependent effects of Pratylenchus penetrans on nitrogen fixation by co-inoculated B. japonicum. Less than 130 inoculated nematodes affected the number and weight of nodules, the density of viable bacteroids in nodules, and nitrogen fixation measured as concentration of ureides in leaves. With more inoculated nematodes, the percentage that invaded the roots increased, and adverse effects on the symbiosis accelerated, leading to non-functional nodules at 4,000 and more nematodes. When P. penetrans invaded roots that had fully established nodules, growth of nodules, density of bacteroids, and nitrogen fixation were affected but not the number of nodules. In contrast, nodulation of already infested roots resulted in a high number of small nodules with decreased densities of bacteroids and nitrogen fixation. P. penetrans invaded and damaged the nodules locally, but they also significantly affected the nodule symbiosis by a plant-mediated mechanism, as shown in an experiment with split-root systems.

In diesem Lehrbuch wird die gesamte Bandbreite des Bachelor-Grundlagenwissens zur Phytomedizin dargestellt. Es enthält den kompakten Begleitstoff für phytomedizinische Lehrveranstaltungen. Die 3. Auflage wurde komplett überarbeitet und tiefer didaktisiert. Sie erscheint in größerem Format und lesefreundlichem Layout. Zahlreiche, z. T. farbige Abbildungen illustrieren zentrale Sachverhalte.

Plant-parasitic nematodes are associated with specifically attached soil bacteria. To investigate these bacteria, we employed culture-dependent methods to isolate a representative set of strains from the cuticle of the infective stage (J2) of the root-knot nematode Meloidogyne hapla in different soils. The bacteria with the highest affinity to attach to J2 belonged to the genera Microbacterium, Sphingopyxis, Brevundimonas, Acinetobacter, and Micrococcus as revealed by 16S rRNA gene sequencing. Dynamics of the attachment of two strains showed fast adhesion in less than two hours, and interspecific competition for attachment sites. Isolates from the cuticle of M. hapla J2 attached to the lesion nematode Pratylenchus penetrans, and vice versa, suggesting similar attachment sites on both species. Removal of the surface coat by treatment of J2 with the cationic detergent CTAB reduced bacterial attachment, but did not prevent it. Some of the best attaching bacteria impaired M. hapla performance in vitro by significantly affecting J2 mortality, J2 motility and egg hatch. Most of the tested bacterial attachers significantly reduced the invasion of J2 into tomato roots, suggesting their beneficial role in soil suppressiveness against M. hapla.

Soil conservation is one of the major challenges for agriculture in the 21st century. For this reason, non-inversion tillage systems including subsidiary crops have become popular over the last three decades in Europe. However, the adoption of new agricultural practices may change the diversity and abundance of certain pests and diseases. For example, plant-parasitic nematodes that are major threats towards cultivated plants may be promoted if good hosts, such as certain subsidiary crops and weeds, occur more frequently. The indigenous plant-parasitic nematode fauna under organic farming systems is already adapted to diverse crop rotations and usually dominated by nematodes with broad host ranges. These may be further enhanced in organic farming systems if non-inversion tillage is introduced, which generally increases the abundance and biomass of certain weeds. We evaluated the early effects of non-inversion tillage and subsidiary crops in an organic wheat-potato rotation on plant-parasitic nematodes in two field experiments in two successive years. The total densities of plant-parasitic nematodes increased from an initial 1260 nematodes (100 ml soil)−1 at the start of the experiment to 1850 and 1700 nematodes (100 ml soil)−1 after wheat under non-inversion and conventional tillage, respectively. Plant-parasitic nematode densities then decreased on average to 1100 and 560 nematodes (100 ml soil)−1 after subsidiary crops and potatoes, respectively. Parasitic nematode densities tended to be higher under non-inversion than conventional tillage, except where oilseed radish and black oats had been used as cover crops. For the latter, no differences between tillage treatments occurred. In the second experiment, about 1700 free-living nematodes (100 ml soil)−1 were found under conventional tillage without mulch while under reduced tillage with mulch their numbers were significantly higher at 3100 nematodes (100 ml soil)−1. We conclude that an appropriate choice of subsidiary crops can be an important management factor for the long term sustainability of non-inversion tillage systems.

Aim. To determine the distribution of sugar beet cyst nematode Heterodera schachtii in Ukraine, to de���� ne its population density in soil, the degree of damage and the ef���� ciency of control measures. Methods. Field survey for soil samples, cyst extraction by ���� otation and sieving method, light microscopy. Results. The examination of 12,130 ha of agricultural ���� elds in six regions of Ukraine, conducted in 2010–2015, recorded the sugar beet cyst nematode to occur in ���� ve of them (Kyiv, Chernihiv, Cherkasy, Khmelnytsky, and Vinnytsia), at a total area of 2,572 ha. Taking into consideration the results of previous nematological surveys, the presence of sugar beet cyst nematode has now been documented for 18 regions of Ukraine. In most regions H. schachtii was present in 10–11 % of the examined sugar and seed producing farms with nematode population densities reaching up to 142,000 eggs and juveniles in 100 cc of soil (710-fold above the economic threshold). Conclusions. The main reasons for this wide distribution of H. schachtii in Ukraine are seen in the negligence of prevention measures, unavailability of documented data on its occurrence (missing surveys), crop rotations with over 20 % of host plants, and unavailability of ef���� cient nematicides and domestic nematode-resistant sugar beet cultivars.

Root-knot nematodes (RKN) are yield devastating plant pathogens. Objective of this study was to investigate the distribution of RKN and their threat to vegetable production in the Pakistani-administered districts of Muzaffarabad, Hattian Bala and Neelum. A survey in more than 130 vegetable fields during summer 2012, 2013 and 2014 revealed a remarkable occurrence and prevalence of RKN in many vegetable crops. RKN were found in 64 % of the fields in Muzaffarabad, 30 % of the fields in Hattian Bala and 24 % of the fields in Neelum. Okra was infested on 26 sites with a gall index range of 3–10, tomato on 26 sites with a gall index of 2–10, cucumber at 13 sites with a gall index of 3–9 and eggplant at 11 sites with a gall index of 3–9. Other hosts infested by RKN included mint, beans, cucurbits and peach. Identification of RKN species was performed morphologically by perineal patterns, by PCR using primers for the IGS2 region or SCAR primers, and some by sequencing of a COI gene fragment. The RKN of this temperate region were mostly identified as tropical species. M. incognita was found in 83 % of the tested fields followed by M. javanica (76 %) and M. arenaria (36 %). M. javanica was the predominant species in Muzaffarabad and Hattian Bala. This is the first comprehensive study on the presence of tropical RKN species in the temperate region of Azad Jammu and Kashmir, Pakistan, and their virulence on vegetable crops.

The relationship between initial population densities (Pi) of Meloidogyne hapla on growth of three rose rootstocks (Rosa corymbifera ‘Laxa’, R. multiflora and R. canina ‘Inermis’) and nematode population development was studied. Each plant species was inoculated with ranges of nematode densities of 0, 0.062, 0.125, 0.25, 0.50, 1, 2, 4, 8, 16, 32, 64 and 128 second-stage juvenile/g soil and were allowed to grow for 9 weeks. Seinhorst yield model math formula was fitted to total fresh biomass data of the rootstocks. The tolerance limits (T) were 0.04, 0.09 and 0.01 J2/g soil and the minimum yield (m) 0.65, 0.47 and 0.43 for R. corymbifera ‘Laxa’, R. multiflora and R. canina ‘Inermis’, respectively. The reproductive factor (Pf/Pi) was highest at low initial nematode densities for all rootstocks and then decreased to below maintenance level with increasing initial population densities. Root gall severity consistently increased with initial nematode population density. Furthermore, number of root galling showed a strong positive relationship with final nematode population per gram root fresh weight. The relation between Pi and Pf was also fitted to the Seinhorst population model (Pf = (M*Pi)/Pi + M/a). Rosa multiflora supported the population of M. hapla to a maximum population density (M) of 27.53 J2/g soil with an estimated average maximum multiplication rate (a) of 24.39. For R. corymbifera ‘Laxa’ and R. canina, the maximum multiplication rate was 4.34 and 3.62 and the maximum population density 6.08 and 4.78 J2/g dry soil, respectively. Hence, it was demonstrated that all three rootstocks were susceptible to even low initial nematode densities and therefore are considered good hosts for M. hapla

Laboratories working with regulated plant-parasitic nematodes need to ensure that those nematodes are contained within the quarantine facility. Solid or liquid waste produced during the nematode extraction process has to be deposited in such a way that there is no risk of nematodes spreading. Autoclaving works well for solid waste but uses substantial amounts of energy and thus is often considered too expensive for the enormous amount of wastewater accumulating during nematode extraction. Therefore, there is considerable interest in using less energy-consuming alternatives, such as sedimentation basins. However, published information on the efficacy of sedimentation basins in retaining plant-parasitic nematodes is almost non-existent. In this study, the efficacy of a three-step sedimentation system under routine and artificially nematode-enriched conditions was investigated. Under all experimental conditions, nematode cysts or part of cysts were never found to escape the sedimentation system. This also accounts for plant-parasitic nematodes (eggs and vermiform stages) during routine operation. However, under artificially nematode-enriched conditions (supply of up to several million nematodes) and maximum water flow rates, single specimens of plant-parasitic nematodes were detected in the effluent of the last sedimentation basin that feeds into the closed municipal sewage system. Although wastewater treatment was not investigated in this study, the combination of a system of sedimentation basins plus subsequent wastewater treatment in sewage plants is considered a cost-effective method to contain plant-parasitic nematodes during routine operation.

Plant protection via disease-suppressive bacteria in desert farming requires specific biological control agents (BCAs) adapted to the unique arid conditions. We performed an ecological study of below-ground communities in desert farm soil and untreated desert soil, and based on these findings, selected antagonists were hierarchically evaluated. In contrast to the highly specific 16S rRNA fingerprints of bacterial communities in soil and cultivated medicinal plants, internal transcribed spacer profiles of fungal communities were less discriminative and mainly characterised by potential pathogens. Therefore, we focused on in vitro bacterial antagonists against pathogenic fungi. Based on the antifungal potential and genomic diversity, 45 unique strains were selected and characterised in detail. Bacillus/Paenibacillus were most frequently identified from agricultural soil, but antagonists from the surrounding desert soil mainly belonged to Streptomyces. All strains produced antibiotics against the nematode Meloidogyne incognita, and one-third showed additional activity against the bacterial pathogen Ralstonia solanacearum. Altogether, 13 broad-spectrum antagonists with antibacterial, antifungal and nematicidal activity were found. They belong to seven different bacterial species of the genera Bacillus and Streptomyces. These Gram-positive, spore-forming bacteria are promising drought-resistant BCAs and a potential source for antibiotics. Their rhizosphere competence was shown by fluorescence in situ hybridisation combined with laser scanning microscopy.

Contamination of fruits and vegetables with Salmonella is a serious threat to human health. In order to prevent possible contaminations of fresh produce it is necessary to identify the contributing ecological factors. In this study we investigated whether the addition of sewage sludge or the presence of plant-parasitic nematodes foster the internalization of Salmonella enterica serovar Typhimurium LT2 into lettuce plants, posing a potential threat for human health. Greenhouse experiments were conducted to investigate whether the amendment of sewage sludge to soil or the presence of plant-parasitic nematodes Meloidogyne hapla or Pratylenchus crenatus promote the internalization of S. Typhimurium LT2 from soil into the edible part of lettuce plants. Unexpectedly, numbers of cultivable S. Typhimurium LT2 decreased faster in soil with sewage sludge than in control soil but not in root samples. Denaturing gradient gel electrophoresis analysis revealed shifts of the soil bacterial communities in response to sewage sludge amendment and time. Infection and proliferation of nematodes inside plant roots were observed but did not influence the number of cultivable S. Typhimurium LT2 in the root samples or in soil. S. Typhimurium LT2 was not detected in the leaf samples 21 and 49 days after inoculation. The results indicate that addition of sewage sludge, M. hapla or P. crenatus to soil inoculated with S. Typhimurium LT2 did not result in an improved survival in soil or internalization of lettuce plants.

Abstract Four Hirschmanniella species are known to occur in Europe: H. gracilis, H. loofi, H. behningi and H. zostericola; a fifth species, H. halophila sp. n., is described from Germany, where it was found along the Elbe estuary and on the adjoining coast of the North Sea. Three other species reported for Europe are considered as species inquirendae or appear to be misidentified. Based on sampling material from Germany, detailed morphological descriptions of H. gracilis, H. loofi and H. behningi are given; H. zostericola has not been found since its first description. The variability, even of characters of diagnostic significance, may be enormous, which makes correct identification difficult if little material is available. Hirschmanniella halophila sp. n. is morphologically very close to H. caudacrena, which has been isolated several times from aquarium plants imported from East Asia to Germany and for which morphological details are given. In Germany, H. gracilis is the most common species and is widely distributed; it is also known from many other European countries. Hirschmanniella loofi (also known from The Netherlands, Belgium, Poland and Italy) is less common. Hirschmanniella behningi, previously reported only from Russia and Sweden, was identified from nine places in Germany, including several coastal sites. Most of the Hirschmanniella records refer to moist soils with reed and other grasses or sedges; only H. gracilis was found exceptionally in arable soil. At many sampling sites, two or even three Hirschmanniella species co-occurred. A table for distinguishing the five European species is presented.